Calling GSL-SE Tuners, diagnostic help.
07-07-04, 01:07 AM
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Calling GSL-SE Tuners, diagnostic help.
Hello, thanks for trying to help. I'm a professional mechanic and have been building hot cars for most of my life with good results. Everything from go-karts, big block muscle cars, to fully modified high tech late models with intercooled superchargers on a SEFI, DIS, V6 putting out V8 killing HP. I know the drill, but there's some things I don't know about this one yet. I'm getting a little fustraited with my recently acquired 1985 SE, my old beat up 1981 RX7 would kill it in a race. I was able to tune the '81 to the point it was faster than I thought it could be but this fuel injection is hiding to many things from me. I don't have enough info on it or experience with the car.
This is a all stock '85 13B with 120K on the clock. Run on high quality low octain pump fuel. Good oil pressure and stays on the thermostat all the time.
This engine runs well at normal speeds, starts quickly without help, makes good torque off idle and cruises fine. At WOT it does well but never develops its full rated power (compaired to my '81 12A at least). Up to half throttle it's cool, but at WOT and high RPMs it starts to make a irregular popping noise sort of like muffled microwave pop-corn, this is accompanied with slight mis-fire like jerks in power. Power falls off quickly at this point. I've noted that with a stock coil it happens at a lower RPM/load than with a MSD Blaster coil, it's about 4500 with one and 5300 with the other.
Good stuff: The TPS is in adjustment.
The exhaust isn't clogged.
The secondary actuator ports have just been restored and are fully functional, this actually made the problem a little worse.
The main fuel filter is fresh, but I was just told there is another in tank filter or pump though in another post. The distributor cap and rotor look better than my fast 12A and the wires and plugs are fresh.
Coils have been swapped and this only modified the problem.
I've done the ATF treatment, which helped overall performance.
Ignition timing is set to stock.
I run light mix oil in the fuel, this helped power also but didn't help with the problem.
The throttle body and intake have been removed and cleaned out.
New intake and exhaust gaskets.
No vacuum leaks.
Fan clutch is working properly.
The Vane Airflow Meter has been cleaned and is working freely.
Good battery and cables.
Unknowns, bad stuff:
Fuel pressure, I haven't checked it yet. Haynes manual is vauge, what should it be at WOT.
02 sensor, looks defunct. I'm used to these not effecting WOT perfomance, do they on this system? The idle air control valves aren't working.
The EVAP emmissions system isn't functioning, the tank always has a lot of vapor pressure, it whistles at me when the caps on tight and it gets hot.
The voltage gauge reads a little lower than it should. Do these cars have a ground strap from body to battery?
The Trail and Lead coil positives have a home made jumper wire connecting them together?
Thanks,
Vernon
This is a all stock '85 13B with 120K on the clock. Run on high quality low octain pump fuel. Good oil pressure and stays on the thermostat all the time.
This engine runs well at normal speeds, starts quickly without help, makes good torque off idle and cruises fine. At WOT it does well but never develops its full rated power (compaired to my '81 12A at least). Up to half throttle it's cool, but at WOT and high RPMs it starts to make a irregular popping noise sort of like muffled microwave pop-corn, this is accompanied with slight mis-fire like jerks in power. Power falls off quickly at this point. I've noted that with a stock coil it happens at a lower RPM/load than with a MSD Blaster coil, it's about 4500 with one and 5300 with the other.
Good stuff: The TPS is in adjustment.
The exhaust isn't clogged.
The secondary actuator ports have just been restored and are fully functional, this actually made the problem a little worse.
The main fuel filter is fresh, but I was just told there is another in tank filter or pump though in another post. The distributor cap and rotor look better than my fast 12A and the wires and plugs are fresh.
Coils have been swapped and this only modified the problem.
I've done the ATF treatment, which helped overall performance.
Ignition timing is set to stock.
I run light mix oil in the fuel, this helped power also but didn't help with the problem.
The throttle body and intake have been removed and cleaned out.
New intake and exhaust gaskets.
No vacuum leaks.
Fan clutch is working properly.
The Vane Airflow Meter has been cleaned and is working freely.
Good battery and cables.
Unknowns, bad stuff:
Fuel pressure, I haven't checked it yet. Haynes manual is vauge, what should it be at WOT.
02 sensor, looks defunct. I'm used to these not effecting WOT perfomance, do they on this system? The idle air control valves aren't working.
The EVAP emmissions system isn't functioning, the tank always has a lot of vapor pressure, it whistles at me when the caps on tight and it gets hot.
The voltage gauge reads a little lower than it should. Do these cars have a ground strap from body to battery?
The Trail and Lead coil positives have a home made jumper wire connecting them together?
Thanks,
Vernon
Last edited by NewRXr; 07-07-04 at 01:15 AM.
07-07-04, 06:21 AM
#2
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Welcome to the club Vernon. I'm just down the road from you. Glad to see a real mechanic working on the 7. Myself, I've been driving and working on them for 15 years.
About your problem. I'm not an expert--and there are a few on the forum--but I'll give my 2 cts.
Two things came to my mind: fuel and ignition. Sounds like you have the fuel checked out pretty good. You're right there are more fuel filters. One in the tank, and there is a tiny strainer inline within the fuel pump. It's located in the outlet of the pump. Looks like a tiny cone strainer made of plastic. Worth checking.
The fuel pump should develop a dead head pressure of 49.8-71.1 psi. That's a good check for a healthy pump. Next check out the FPR. Put a gage in the fuel supply line to the engine--right by where the oil filter is. It should read about 28.44 psi with the engine idling. Disconnect the vacuum line from the FPR and it should go up to about 37 psi.
For ignition, I would check to make sure the vacuum advance is working correctly. Lube it up and test it with a vacuum. Is there any chance your wires got crossed when modifying the ignition system. The popping sound you talk about could be detonation which is very bad for the rotary and could ruin the engine quickly. I've never heard it myself but others talk of it sounding like popcorn. On a NA it's hard to get detonation so something must really be out of wack and for an NA ignition is the likely cause. On my turbo I hope I never hear it. Double check your wiring--sounds like it's firing when it shouldn't. The jumper you talk about does not sound good. I'd take it out unless it matches the stock set-up.
Good wiring diagrams and the FSM can be had at www.iluvmyrx7.com.
Make sure you have the right spark plugs, use only stock Denso's or NGK. I'd also get the injectors cleaned if they haven't been serviced--you only have two of them.
I gotta go to work and I'll check in later. By then others will have chimed in.
HTH,
Scott
About your problem. I'm not an expert--and there are a few on the forum--but I'll give my 2 cts.
Two things came to my mind: fuel and ignition. Sounds like you have the fuel checked out pretty good. You're right there are more fuel filters. One in the tank, and there is a tiny strainer inline within the fuel pump. It's located in the outlet of the pump. Looks like a tiny cone strainer made of plastic. Worth checking.
The fuel pump should develop a dead head pressure of 49.8-71.1 psi. That's a good check for a healthy pump. Next check out the FPR. Put a gage in the fuel supply line to the engine--right by where the oil filter is. It should read about 28.44 psi with the engine idling. Disconnect the vacuum line from the FPR and it should go up to about 37 psi.
For ignition, I would check to make sure the vacuum advance is working correctly. Lube it up and test it with a vacuum. Is there any chance your wires got crossed when modifying the ignition system. The popping sound you talk about could be detonation which is very bad for the rotary and could ruin the engine quickly. I've never heard it myself but others talk of it sounding like popcorn. On a NA it's hard to get detonation so something must really be out of wack and for an NA ignition is the likely cause. On my turbo I hope I never hear it. Double check your wiring--sounds like it's firing when it shouldn't. The jumper you talk about does not sound good. I'd take it out unless it matches the stock set-up.
Good wiring diagrams and the FSM can be had at www.iluvmyrx7.com.
Make sure you have the right spark plugs, use only stock Denso's or NGK. I'd also get the injectors cleaned if they haven't been serviced--you only have two of them.
I gotta go to work and I'll check in later. By then others will have chimed in.
HTH,
Scott
07-07-04, 07:13 AM
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Thanks for the long answer Scott, that gives me somethings to look for. I like what you've done with your car, looks neat. Maybe we'll meet up at a Houston Club function sometime. I wanted to go last night but the work I did to the intake last week didn't fix the car.
It could be detonation, a light case with maybe three to five pops before I change gears. If so it would probably be from leaning out the fuel mixture at full load. This would go back to fuel supply and pressure. I'll look into this more (now that I've got almost a full tank to burn).
Vernon
It could be detonation, a light case with maybe three to five pops before I change gears. If so it would probably be from leaning out the fuel mixture at full load. This would go back to fuel supply and pressure. I'll look into this more (now that I've got almost a full tank to burn).
Vernon
07-07-04, 07:42 AM
#4
84SE-EGI helpy-helperton
Hey, welcome to the boards;
What Scott talks about with the 'jumper' between your leading and trailing ignition is very likely the cause of your problem. This should not be there, and will negatively affect performance. Disconnect it and you'll know right away if it's a contributing factor or the cause of your problem.
On a rotary engine, even the 12a's, the leading and trailing ignition have to function independently of each other to fire the engine smoothly and efficiently. In fact, this is SO important that some of the pre-79 12a's had 2 distributors and rotors to control leading and trailing ignition. Once Mazda sorted out the distributor design for a single-distributor to do it all, they all came with 1 distributor. Leading fires on each compression cycle, followed by Trailing ignition on each compression cycle, PLUS on the opposite rotor which is in exhaust - this helps to complete the burn of the fuel/air charge, and is timed by the ignition system to occur on cue.
If you have a jumper set between the + on each coil, your effectively shorting out the timing signal between coils which is going to lead to some very strange ignition pulses, most likely in off-time events, which could be causing pinging, which is deadly to a rotary engine. As a mechanic, equate this to a pre-ignition or detonation caused by low octane fuel in a high compression engine (not that rotary's are high-compression, just a similar net result). All the ignition pressure is then centered on the apex seals and side seals and will very quickly lead to an engine popping a seal and losing compression.
Give that a shot and report back. I think you'll be glad you did,
What Scott talks about with the 'jumper' between your leading and trailing ignition is very likely the cause of your problem. This should not be there, and will negatively affect performance. Disconnect it and you'll know right away if it's a contributing factor or the cause of your problem.
On a rotary engine, even the 12a's, the leading and trailing ignition have to function independently of each other to fire the engine smoothly and efficiently. In fact, this is SO important that some of the pre-79 12a's had 2 distributors and rotors to control leading and trailing ignition. Once Mazda sorted out the distributor design for a single-distributor to do it all, they all came with 1 distributor. Leading fires on each compression cycle, followed by Trailing ignition on each compression cycle, PLUS on the opposite rotor which is in exhaust - this helps to complete the burn of the fuel/air charge, and is timed by the ignition system to occur on cue.
If you have a jumper set between the + on each coil, your effectively shorting out the timing signal between coils which is going to lead to some very strange ignition pulses, most likely in off-time events, which could be causing pinging, which is deadly to a rotary engine. As a mechanic, equate this to a pre-ignition or detonation caused by low octane fuel in a high compression engine (not that rotary's are high-compression, just a similar net result). All the ignition pressure is then centered on the apex seals and side seals and will very quickly lead to an engine popping a seal and losing compression.
Give that a shot and report back. I think you'll be glad you did,
Last edited by LongDuck; 07-07-04 at 07:44 AM.
07-07-04, 02:53 PM
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I'm thinking that someone may have put that jumper on because they had a bad ignitor?
Sounds like a jury rig to get it working to me.
Definately take it off and see what happens.
Sounds like a jury rig to get it working to me.
Definately take it off and see what happens.
07-07-04, 07:12 PM
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Originally posted by LongDuck
PLUS on the opposite rotor which is in exhaust - this helps to complete the burn of the fuel/air charge, and is timed by the ignition system to occur on cue.
PLUS on the opposite rotor which is in exhaust - this helps to complete the burn of the fuel/air charge, and is timed by the ignition system to occur on cue.
07-07-04, 09:44 PM
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Re: Calling GSL-SE Tuners, diagnostic help.
Hi Vernon.
As long as the jumper is on the positive side of the coils, as you've said, it is not a problem as both positives normally come from the same main relay anyway.
It's the coil negatives that are switched by the ignitors.
I would definitely check the two strainers and fuel pressure (using the numbers Rex4Life mentioned) first.
But many people have disconnected the vacuum advance without problem.
Stock, the ground cable connects the battery to the rear of the engine block but has a terminal tapped into it half way which bolts to the drivers side strut tower for the chassis ground.
You might want to double-check the voltage with a proper meter if you haven't already as the stock gauge is often not very accurate. But as long as the voltage comes up off-idle, I wouldn't think it could cause your problems. If someone replaced the ground cable and neglected the chassis ground though...
I would expect to see more than ignition problems if that were the case but as always with grounds, who knows?
For the whistle at the tank: mine also does it on occasion. It's the check and cut valve near the pump at fault. I've never felt a performance difference during it's "singing".
The O2 sensor would not cause the problem.
As you are not new to rotaries, I wont ask if the plug wires might be crossed...
Sure sounds like fuel or ignition. The pops may be unburned fuel from an ignition misfire burning in the exhaust, making me lean towards ignition. Good luck.
-John
As long as the jumper is on the positive side of the coils, as you've said, it is not a problem as both positives normally come from the same main relay anyway.
It's the coil negatives that are switched by the ignitors.
I would definitely check the two strainers and fuel pressure (using the numbers Rex4Life mentioned) first.
But many people have disconnected the vacuum advance without problem.
Originally posted by NewRXr
Do these cars have a ground strap from body to battery?
Do these cars have a ground strap from body to battery?
You might want to double-check the voltage with a proper meter if you haven't already as the stock gauge is often not very accurate. But as long as the voltage comes up off-idle, I wouldn't think it could cause your problems. If someone replaced the ground cable and neglected the chassis ground though...
I would expect to see more than ignition problems if that were the case but as always with grounds, who knows?
For the whistle at the tank: mine also does it on occasion. It's the check and cut valve near the pump at fault. I've never felt a performance difference during it's "singing".
The O2 sensor would not cause the problem.
As you are not new to rotaries, I wont ask if the plug wires might be crossed...
Sure sounds like fuel or ignition. The pops may be unburned fuel from an ignition misfire burning in the exhaust, making me lean towards ignition. Good luck.
-John
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07-09-04, 07:01 PM
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I ran it with a fuel pressure guage taped to the windshield on the way home today. Based on my observations fuel pressure doesn't seem to be the issue. At WOT I saw ~38-39 steady up onto the top of the tach where the missing would occur. At that point the needle would just bounce or jerk at bit, more from the pressure fluctuation in the intake manifold than a drop in supply pressure. I've seen fuel delivery issues numerous times at my job and this didn't appear similar. Also my 350 HP/430 FT.LBs. 3.8 V6 Thunderbird SC has always fluctutated slightly worse than this at WOT and it never caused similar problems. I'll be checking the ignition system over this weekend.
Vernon
Vernon
07-12-04, 07:18 PM
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Ignition Scope testing...
****UPDATE****
I found cut off switches wired into each coil power circut and located near the front seat posts. The job was crappy, no solder, only crimp connects, and smaller gauge wires. At about 7 feet for each circut the voltage drop at the coils was inevitable. This crap has now been removed and new eyelets have been soldered onto the factory wires that now connect directly to the coils again. I think the "jumper" was installed by someone else who didn't know about the kill switches when one was accidently tripped and that coil went dead. With the jumper both coils were being fed from one poorly wired power supply circuit.
The ignition switch was always a little off, it would stop cranking when turned all the way. It had a "crank" sweet spot. Friday it started killing the igniton circuts when the key was released from crank to run. I had to hold it just off of crank to stay running. Luckily I had an 85 switch extra laying around for about a year now. I used it. This problem and potential cause of other woes is gone.
While the car runs better still, the problem is still there.
Now for the findings on the scope, I have a problem in the distributor. So far I've been checking the leading ignition. The primary coil firing is messed up. Instead of a clean swithing wave it is messy, and every tenth or so firing the primary wave is fuzzy as all get out. When one of these "fuzzy" primary switches takes place the motor skips. The primary voltage is very high, at about 450 Volts, but the messy waves are hanidicapping the secondary voltages. They actually drop under load, the opposite of what I'm used to. The secondary spark will peak at about 20 KV right off idle at WOT then drop to about 12.5 KV and as low as 9 KV on the miss. Obviously I'm blowing out my spark at high RPM loads with these messed up primary signals preventing a clean secondary spark.
I can get a reman distributor for $125 but I'm on a budget, so I have a question.
QUESTION:
Can I swap the distributor over from my good running '81 12A? I think the advance mechanisims would have to be swapped to retain the proper timing curves but other than that will they swap? I think they do but I'm not sure so I ask. I'm quite the whiz at recalibrating old Ford timing curves in those distributors so I know what to expect. I just don't know for certain that it will fit and function in the 13B.
Thanks for any help here.
Vernon.
I found cut off switches wired into each coil power circut and located near the front seat posts. The job was crappy, no solder, only crimp connects, and smaller gauge wires. At about 7 feet for each circut the voltage drop at the coils was inevitable. This crap has now been removed and new eyelets have been soldered onto the factory wires that now connect directly to the coils again. I think the "jumper" was installed by someone else who didn't know about the kill switches when one was accidently tripped and that coil went dead. With the jumper both coils were being fed from one poorly wired power supply circuit.
The ignition switch was always a little off, it would stop cranking when turned all the way. It had a "crank" sweet spot. Friday it started killing the igniton circuts when the key was released from crank to run. I had to hold it just off of crank to stay running. Luckily I had an 85 switch extra laying around for about a year now. I used it. This problem and potential cause of other woes is gone.
While the car runs better still, the problem is still there.
Now for the findings on the scope, I have a problem in the distributor. So far I've been checking the leading ignition. The primary coil firing is messed up. Instead of a clean swithing wave it is messy, and every tenth or so firing the primary wave is fuzzy as all get out. When one of these "fuzzy" primary switches takes place the motor skips. The primary voltage is very high, at about 450 Volts, but the messy waves are hanidicapping the secondary voltages. They actually drop under load, the opposite of what I'm used to. The secondary spark will peak at about 20 KV right off idle at WOT then drop to about 12.5 KV and as low as 9 KV on the miss. Obviously I'm blowing out my spark at high RPM loads with these messed up primary signals preventing a clean secondary spark.
I can get a reman distributor for $125 but I'm on a budget, so I have a question.
QUESTION:
Can I swap the distributor over from my good running '81 12A? I think the advance mechanisims would have to be swapped to retain the proper timing curves but other than that will they swap? I think they do but I'm not sure so I ask. I'm quite the whiz at recalibrating old Ford timing curves in those distributors so I know what to expect. I just don't know for certain that it will fit and function in the 13B.
Thanks for any help here.
Vernon.
07-12-04, 10:03 PM
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NEVERMIND:
It was due to a MSD Blaster coil being used on the stock ignitor without a balast resistor. I put the scope on the trailing side just to see what was up. It was clean and working well, it has a stock coil because the MSD coil I had on there for a short while shorted from tower to ground. It was a junkyard find so I tossed it without grief.
I had just read in the "No more Ignitors" post that one of the guys was told by MSD techs that we shouldn't run Blaster coils without a balast resistor because their lower resistance might draw to much current for the stock ignitors and cause problems with them. So I pulled the original Diamond coil out and put it in place of the MSD Blaster on the Leading igntion. This made the ignitor fire clean and steady. The secondary spark is stronger and stable at high RPMs.
Well now the car runs strong upto 6000 RPM, not as strong as I would like though. At 6000 the popping comes back. Now that I know the ignition is working properly I'm going to turn my attention back to the fuel. I'm going to flush the injectors tommorrow. This car will be fast or I'll blow it the HELL UP! LOL
It was due to a MSD Blaster coil being used on the stock ignitor without a balast resistor. I put the scope on the trailing side just to see what was up. It was clean and working well, it has a stock coil because the MSD coil I had on there for a short while shorted from tower to ground. It was a junkyard find so I tossed it without grief.
I had just read in the "No more Ignitors" post that one of the guys was told by MSD techs that we shouldn't run Blaster coils without a balast resistor because their lower resistance might draw to much current for the stock ignitors and cause problems with them. So I pulled the original Diamond coil out and put it in place of the MSD Blaster on the Leading igntion. This made the ignitor fire clean and steady. The secondary spark is stronger and stable at high RPMs.
Well now the car runs strong upto 6000 RPM, not as strong as I would like though. At 6000 the popping comes back. Now that I know the ignition is working properly I'm going to turn my attention back to the fuel. I'm going to flush the injectors tommorrow. This car will be fast or I'll blow it the HELL UP! LOL
07-12-04, 10:46 PM
#11
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I'd triple check all the ignition wiring. Given that it has been monkey'd with so much--there's still the chance you missed something. Kudos to your diagnostic skills and from your post I can tell you have alot of good knowledge about this.
I still haven't heard about an NA detonating cause of low fuel. I had one that had a clogging fuel filter--real bad too--and I never had knocks. Went many times where it would bog out and stop--no knocks. Anyway the injector cleaning is still good for maintenance.
The other thing that comes to mind is some sort of cross feed of the ignition at high speed, but I think that happens more with the electronic ignition--not the mechanical one.
Hope you get it running great soon.
Scott
I still haven't heard about an NA detonating cause of low fuel. I had one that had a clogging fuel filter--real bad too--and I never had knocks. Went many times where it would bog out and stop--no knocks. Anyway the injector cleaning is still good for maintenance.
The other thing that comes to mind is some sort of cross feed of the ignition at high speed, but I think that happens more with the electronic ignition--not the mechanical one.
Hope you get it running great soon.
Scott
07-13-04, 11:49 PM
#12
84SE-EGI helpy-helperton
I'm running MSD Blaster coils without the ballast and never had this problem in about 6 months of driving. Not that it would impact the curves to include the resistors, but you shouldn't need them.
It could be something else that still needs to be tuned up, and you've found part of the problem by switching back to the stock coil. Could also be that the MSD blaster that you took out was bad for some reason.
I'd keep looking at the ignition system and check your cap and rotor again - it could be something very simple like cross-talk between your plug leads or the coils to the distributor. Good luck,
It could be something else that still needs to be tuned up, and you've found part of the problem by switching back to the stock coil. Could also be that the MSD blaster that you took out was bad for some reason.
I'd keep looking at the ignition system and check your cap and rotor again - it could be something very simple like cross-talk between your plug leads or the coils to the distributor. Good luck,
07-16-04, 04:10 AM
#14
popping noise could be unspent fuel in the exhaust system. check your deacceleration system, tps, to make sure they are in adjustment. check timing to see if there is a flucuation as you are watching the marks between
leading and trailing. could indicate cross firing although
not very common on a gsle. try changing rotors, i have seen them ground to the dist housing and cause a mess. you checked for fuel pressure, how about volume? at idle revving up the engine does it go to redline easily or struggle? what brand of plugs are you using? the air flow meter even though pin tested is a major factor, they get out of adjustment all the time.
feel free to personally e-mail me at rx7doctor@aol.com
leading and trailing. could indicate cross firing although
not very common on a gsle. try changing rotors, i have seen them ground to the dist housing and cause a mess. you checked for fuel pressure, how about volume? at idle revving up the engine does it go to redline easily or struggle? what brand of plugs are you using? the air flow meter even though pin tested is a major factor, they get out of adjustment all the time.
feel free to personally e-mail me at rx7doctor@aol.com
07-16-04, 07:30 AM
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Thanks for your continued support guys, unfortunatly I do still need it. After the injector flush the car seemed a tad better and that it was what some people would consider fast. I knew it still wasn't right so when things slowed down at the shop I started looking at the distributor and secondary ignition again.
Timing is still at factory specs, vacuum and mechanical advance are still functioning.
The cap and rotor have a very light interference pattern around two of the top contacts. It looks as if they just rubbed enough to make lines on each other but not to cause any physical damage. Otherwise these two components looked relatively fresh. I'll check the rotor for grounding as rx7doctor mentioned.
Under the next internal cap there was some slight oil buildup. Two small cavitys in the botttom plate had oil standing but it wasn't flooded. The pick-ups looked pretty old and rusty. I checked the air gap on both pick-ups and it was withing specs. One thing here has me confused but I think it's just a Haynes manual thing. It tells one to turn the shaft until two of the teeth on the interrupter are aligned with the two pick-ups. Well, with my timing no two line up at the same time. I don't think this matters though. I examined the wires going to and from the ignitors, they looked old but not damaged.
Well there must definatly be something amiss in the distibutor because after a light cleaning and reassembly the car now runs really bad. The "popping" and power fade is worse than ever.
I'm at the point where I want to swap the distributor out of my good running parts car again. Should I change the advance components over between the two OR leave the '81 12A curve in and set the timing to popular 13B total advance reccomendations? Is there any advice for one about to do this job for the first time?
I had so much fun in the '81, I could walk away from GTP's and such. I know this car has the potential to run even better and it really gets to me. Being a professional diagnostic mechanic and amatuer racer I'm used to always having a excellent running car. But as usual it always takes a lot of time and effort. I feel for guys like nekky, if you can't do this yourself and you do find someone who can, who could afford them?
Thanks again,
Vernon
Timing is still at factory specs, vacuum and mechanical advance are still functioning.
The cap and rotor have a very light interference pattern around two of the top contacts. It looks as if they just rubbed enough to make lines on each other but not to cause any physical damage. Otherwise these two components looked relatively fresh. I'll check the rotor for grounding as rx7doctor mentioned.
Under the next internal cap there was some slight oil buildup. Two small cavitys in the botttom plate had oil standing but it wasn't flooded. The pick-ups looked pretty old and rusty. I checked the air gap on both pick-ups and it was withing specs. One thing here has me confused but I think it's just a Haynes manual thing. It tells one to turn the shaft until two of the teeth on the interrupter are aligned with the two pick-ups. Well, with my timing no two line up at the same time. I don't think this matters though. I examined the wires going to and from the ignitors, they looked old but not damaged.
Well there must definatly be something amiss in the distibutor because after a light cleaning and reassembly the car now runs really bad. The "popping" and power fade is worse than ever.
I'm at the point where I want to swap the distributor out of my good running parts car again. Should I change the advance components over between the two OR leave the '81 12A curve in and set the timing to popular 13B total advance reccomendations? Is there any advice for one about to do this job for the first time?
I had so much fun in the '81, I could walk away from GTP's and such. I know this car has the potential to run even better and it really gets to me. Being a professional diagnostic mechanic and amatuer racer I'm used to always having a excellent running car. But as usual it always takes a lot of time and effort. I feel for guys like nekky, if you can't do this yourself and you do find someone who can, who could afford them?
Thanks again,
Vernon
07-18-04, 11:11 AM
#17
This power loss you speak of sounds similar to what I had a year and a half ago.
First off replace all the vacuum lines if you haven't all ready. This adds to the problem. There are some hidden nipples around the Re-egi box that if not hooked up the car will run terrible. There should be 9 vacuum nipples on the manifold itself. One more on the lower half of the intake manifold.
But the solution to your problem is in the "rats nest" as they call it. You'll notice two colored connectors on the drivers side of the manifold, a orange one and a green one.
I don't remember which one you need to bypass, but all you do is unplug one and drive the car. if the problem isn't solved plug it back in and unplug the second one.
Then if that does the trick, run a jumper wire on that connector from one pin to the other and wrap it in tape and keep it unpluged.
This is what I had to do. Never had that problem since.
First off replace all the vacuum lines if you haven't all ready. This adds to the problem. There are some hidden nipples around the Re-egi box that if not hooked up the car will run terrible. There should be 9 vacuum nipples on the manifold itself. One more on the lower half of the intake manifold.
But the solution to your problem is in the "rats nest" as they call it. You'll notice two colored connectors on the drivers side of the manifold, a orange one and a green one.
I don't remember which one you need to bypass, but all you do is unplug one and drive the car. if the problem isn't solved plug it back in and unplug the second one.
Then if that does the trick, run a jumper wire on that connector from one pin to the other and wrap it in tape and keep it unpluged.
This is what I had to do. Never had that problem since.
07-24-04, 11:18 AM
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One week later, getting closer, almost crazy.
Originally Posted by rx7doctor
check timing to see if there is a flucuation as you are watching the marks between leading and trailing. could indicate cross firing although not very common on a gsle. try changing rotors, i have seen them ground to the dist housing and cause a mess. at idle revving up the engine does it go to redline easily or struggle?
First off let me vent. FRIGGIN CAR! ANTIQUE JAPANESE PIECE OF @$#*! I'M GONNA BURN YOUR @#$ DOWN YOU SORRY-NO GOOD-NO RUNNIN'-BEEAUCH! AHHHHHHHGH!
Alright, let me calm down. I spent my free time last week on the distributors. I pulled both, from my good running '81 and the GSL-SE. The SE dizzy had some oil residue and the pick up coils looked ratty, one ignitor is suspect. The 12A dizzy had nice looking and checking pick-ups and ignitors, but rusted flyweights and bearing plate.
So I built one good distributor using the best parts, cleaned up, lubed, and restored to full function. I used the 13B timing mechanisims, mechanical and vacuum and they are very different in respect to amount of advance. I checked all components as well as I could with an ohm meter. I used the test light test on all the ignitors and found one to be incosistant at best, it was one of the original 13B ignitors that I have been using. So I used the ignitors off the 12A. The pick-up coils from the 12A were also used. The cap and rotor from the 13B were much better looking than the worn 12A stuff so were reused.
Now I have this nice clean fully functioning distributor. So I put it in. The engine started right up. I proceeded to set intial timing on the leading plug without issue. Then I tried to set the trailing and ran into "THE PROBLEM?" The trailing ignition is being fired in sync with the leading. I moved the trailing vacumm unit in and out with no effect on the firing time. This was confusing, so I checked and rechecked myself to make sure I was doing this correctly and I was. If I revved the engine some every so often the trailing would fire on the trailing mark. The only way I can get the trailing ignintion to fire with it's pick-up every time is to disable the leading ignition (unplug coil power). With the leading ignition disabled the trailing will then fire on it's own pick up and is setable with the vacuum can as it should be. But if I have the leading working the trailing fires right with it and is changeable only by turning the dizzy.
I have ohmed the wire harness and the wiring isn't crossing somewhere in the looms. I uncovered as much as I could without removeing it completely and tearing all wires apart and it looks fine. The secondary cables (spark plug and coil wires) are good and not leaking, are separated by looms, and worked fine on the 12A. I see or hear no secondary crossfiring or leaking.
Coils both ohm at slightly less than 1 ohm across the primary terminals. Using the meter from the secondary post to the primary gets 8.28k and 8.74. With power leads (bat or +) connected to both coils there is only 2.6 ohms from the primary (-) post on one coil to the other, I don't understand this as it seems they are not separated as much as I thought they should be.
The ignitors are the only place I could find a significant difference with the ohm meter.
Ignitors:
POS TO GROUND
Leading - 46K ohms
Trailing - 50K
POS TO NEG posts
Leading - 1.26 MOhms
Trailing - 0.7 MOhms
NEG TO GROUND
Leading - 1.19 MOhms
Trailing - 184K Ohms
I don't know what this means as I've never found any in depth technical information on what the ignitors really are and do. All I think they are is an electronic pulse amplifier. How one would be triggered by the other is beyond my knowledge as of yet. Both of these ignitors worked well on the 12A and passed the test light check. This is were I hope you guys can help.
I'm going out right now and swap the cap and rotor just because at this point it's the only thing I havn't tried. I'll be tinkering with it until I find something or I get some advice on what to try next. There's a Houston RX-7 Club scenic drive meet next Saturday that I really want to make, yea the car would run but I want it to run right and not be scared of it breaking down or falling to far behind the pack. This car is testing my patience beyond belief.
Thanks again,
Vernon
07-25-04, 08:02 AM
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I got that worked out, it seems it is just the timing light being very sensitive and problematic when hot. Sorry I couldn't go back and edit that if you've just labored over it. I drove the car, it's not much better. I set the timing up about 7 degrees with a 10 degree split. This accounts for the small increase in power. I also drove it with the vacuum advance lines plugged to check for rat's nest issues but it ran the same at WOT with less part throttle power.
I don't know what to do with this car.
I don't know what to do with this car.
07-25-04, 11:11 AM
#21
i know you have checked your tps but re-check it. it may help. make sure it is in adjustment. i check mine every time i change the oil. also, have you cloeaned the BACV? this helped my engine when it was missing. i removed it, took it apart, cleaned it, re-sealed it and installed it. better idle quality and smoother all together. the ignitors can heat soak and cause problems. corrosion appears on the back side of them and acts as an insulator and causes problems.
08-21-04, 09:52 AM
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Hey get a load of this, my check and cut valve was part of the problem. It was so bad whenever I drove the car the pressure would build up in the tank to the point that it would whistle out somewhere and I could hear it inside the car until it cooled down. It's been a series of baby steps but I've gone from somewhat slow to pretty fast and would you believe that "insignificant" check and cut valve was worth a big chunk of horsepower.
Let me explain, I was flipping through my Haynes manual and came across the fault diagnostics section in the front. In section 7, "Lack of power, poor acceleration", step three says "Examine the crankcase and evaporative emission control systems and in particular check for defects in the check and cut valve and for clogged hoses in the evaporative line." Now I'm a professional mechanic who actually specializes in emissions. On any other car I can think of a problem in this area would only be a minor pollution producer and this would have no significant effect on how the engine ran. So like you guys I found this hard to understand and studied the Haynes manual, the factory service manual, and the car to try and determine how this could cause a low power condition but I couldn't figure it out. There is a serious lack of engine control theory information about first gen RX-7's available. I had been advised on the board that it was a non-issue on their cars. Finally I just determined I had nothing to loose and at least I could possibly get rid of the annoying whistle by repairing the stuff.
So I removed the check and cut valve from my SE and my '81 parts car. Both were clogged up according to the testing procedures in print. The '81 car ran super good, it would smoke fast cars and it was stock, this just adds to my confusion. So I disassembled both and started cleaning them out with carb/choke cleaner. The build up was stubborn and it took a while to get it all out. During this time one of the valve bodies was accidentally knocked off the workbench and cracked apart when it hit the floor, these parts have become brittle over the years so handle them carefully. Upon reassembly of the cleaned out valve I found it still wouldn't open at the pressures listed in the book, which was low enough to be checked by mouth pressure. So I grabbed a portable 12V air compressor with a beach ball type nozzle adapter and forced air and carb cleaner through the ports used for testing until this freed them up to the point it would pass the tests. I slid under the car and used the carb spray and air pump technique on the vapor lines also. Then I reinstalled the valve. I went under the hood and removed the purge valve and used carb cleaner to flush it and it's attaching hoses. I then checked for vacuum and free flow on the proper attaching hoses. All was working properly so I reassembled the system. I started the car and let it run for a while and everything seemed fine, the whistling never started.
The next day on the way to work I found the engine was making significantly more power across the entire range. It was enough to really feel the difference and I'm no rookie, I've been building seriously fast streetcars for over 19 years. When I say a significant difference there is one. I would estimate at least 10 HP across the board. Now tank pressure is always normal and it's been about a month. The bump in power is still there also. While this is obviously a good thing and I recommend anyone to duplicate my efforts I still would like to know what the heck happened with the fuel injection because of a clogged up check and cut valve and or purge valve.
Let me explain, I was flipping through my Haynes manual and came across the fault diagnostics section in the front. In section 7, "Lack of power, poor acceleration", step three says "Examine the crankcase and evaporative emission control systems and in particular check for defects in the check and cut valve and for clogged hoses in the evaporative line." Now I'm a professional mechanic who actually specializes in emissions. On any other car I can think of a problem in this area would only be a minor pollution producer and this would have no significant effect on how the engine ran. So like you guys I found this hard to understand and studied the Haynes manual, the factory service manual, and the car to try and determine how this could cause a low power condition but I couldn't figure it out. There is a serious lack of engine control theory information about first gen RX-7's available. I had been advised on the board that it was a non-issue on their cars. Finally I just determined I had nothing to loose and at least I could possibly get rid of the annoying whistle by repairing the stuff.
So I removed the check and cut valve from my SE and my '81 parts car. Both were clogged up according to the testing procedures in print. The '81 car ran super good, it would smoke fast cars and it was stock, this just adds to my confusion. So I disassembled both and started cleaning them out with carb/choke cleaner. The build up was stubborn and it took a while to get it all out. During this time one of the valve bodies was accidentally knocked off the workbench and cracked apart when it hit the floor, these parts have become brittle over the years so handle them carefully. Upon reassembly of the cleaned out valve I found it still wouldn't open at the pressures listed in the book, which was low enough to be checked by mouth pressure. So I grabbed a portable 12V air compressor with a beach ball type nozzle adapter and forced air and carb cleaner through the ports used for testing until this freed them up to the point it would pass the tests. I slid under the car and used the carb spray and air pump technique on the vapor lines also. Then I reinstalled the valve. I went under the hood and removed the purge valve and used carb cleaner to flush it and it's attaching hoses. I then checked for vacuum and free flow on the proper attaching hoses. All was working properly so I reassembled the system. I started the car and let it run for a while and everything seemed fine, the whistling never started.
The next day on the way to work I found the engine was making significantly more power across the entire range. It was enough to really feel the difference and I'm no rookie, I've been building seriously fast streetcars for over 19 years. When I say a significant difference there is one. I would estimate at least 10 HP across the board. Now tank pressure is always normal and it's been about a month. The bump in power is still there also. While this is obviously a good thing and I recommend anyone to duplicate my efforts I still would like to know what the heck happened with the fuel injection because of a clogged up check and cut valve and or purge valve.
06-29-05, 09:30 PM
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For those who remember this I found the answer last week (after I fixed the grounding secondary coil primary lead the subject of my last HELP post (What's normal injector duty cylcle at idle- SE)). The main problem all this time was the Air Control Valve and Check Valves. Mine was an "air out of control valve", all the valves in it were leaky. The check valve in the intake was gone and the check valve in the catalyst air injection tube wasn't able to prevent reversion. I spent forty bucks on check valves and gasket at Mazda but wasn't about to pony up for a new ACV. So I scored one on the board for cheap and it was a winner.
The car runs as good as I could hope after all it's been through. It's as fast as my '81 was and that car was a ringer. I'm sure I could make it faster than my old 7 with a fresh cat or the header out in the shed but the SE is now my son's car and it's more than fast enough for him at 16.
I was able to reset the idle speed adjuster way down, and turn the Variable Resistor down from full rich to just less than half. It starts right up when cold now, never did that. Runs like a top, shoe wieght will maintain any legal speed. It'll even lay rubber if you try.
In the last year+ I've went through everything on the engine control, all has been rebuilt, replaced, checked and rechecked, or adjusted. So I've learned a lot, the hard way as usual. Hopefully I'll be able to help others on here with what I've learned.
Vernon
The car runs as good as I could hope after all it's been through. It's as fast as my '81 was and that car was a ringer. I'm sure I could make it faster than my old 7 with a fresh cat or the header out in the shed but the SE is now my son's car and it's more than fast enough for him at 16.
I was able to reset the idle speed adjuster way down, and turn the Variable Resistor down from full rich to just less than half. It starts right up when cold now, never did that. Runs like a top, shoe wieght will maintain any legal speed. It'll even lay rubber if you try.
In the last year+ I've went through everything on the engine control, all has been rebuilt, replaced, checked and rechecked, or adjusted. So I've learned a lot, the hard way as usual. Hopefully I'll be able to help others on here with what I've learned.
Vernon
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