Brainstorming on engine issues
12-07-15, 04:54 PM
#1
Brainstorming on engine issues
I really wish I wasn't so busy this week with work but still can think about issues. I picked up a 93 with spark issues, and after running through the wiring harness and coils, I found and fixed wiring and got it running. Starts up fairly easily and today decided to drive it to the gas station for some fuel since it seemed low.
1.The cooling fans stay running on low speed all the time unless key is off, not sure if that was a mod.
2. Smoke coming from stock twin turbo exhaust area, does have what looks to be a new full exhaust. Smell is of oil, not sure besides the one visible oil inlet line that runs to it.
3. Idles a smidge rough, had been sitting for almost a year not running.
4. Gets a bit warm when idling long periods of time, probably have to bleed air out. Has the aftermarket ast where the ps would be.
5. Although I wasn't trying to be hard on it for the short 5 min drive, it can rev freely, but under power, when the turbo's kick in, a wall is hit.
When time arises, I will want to do a cooling pressure system check/thermostat test, check for vacuum/pressure leaks, replace fluids as needed, get gauges for vacuum/boost.
Maybe someone has ran into these problems or they are common and would like to hear from them as I dealt with 86-88's maybe 9+ years ago but not an fd. The space in there is just mind-numbing.
Extra sightings. Was told the engine may be recently rebuilt and has good compression(80-90's), engine mount bolts were loose so tightened them up. The LIM has a new gasket as seen from underneath. No a/c, p/s, air pump. Had taken the TB off when checking coils and had some oil in there that I wiped out. Has like a dry sump looking deal on the bottom of gas tank that is capped off as well as a fuel cooler on the back pumper capped as well. Also did the check engine light for codes and cleared up all but a couple including fuel pump relay. There is a relay with wire running to battery in the back, so guessing there may be something there to check as well.
1.The cooling fans stay running on low speed all the time unless key is off, not sure if that was a mod.
2. Smoke coming from stock twin turbo exhaust area, does have what looks to be a new full exhaust. Smell is of oil, not sure besides the one visible oil inlet line that runs to it.
3. Idles a smidge rough, had been sitting for almost a year not running.
4. Gets a bit warm when idling long periods of time, probably have to bleed air out. Has the aftermarket ast where the ps would be.
5. Although I wasn't trying to be hard on it for the short 5 min drive, it can rev freely, but under power, when the turbo's kick in, a wall is hit.
When time arises, I will want to do a cooling pressure system check/thermostat test, check for vacuum/pressure leaks, replace fluids as needed, get gauges for vacuum/boost.
Maybe someone has ran into these problems or they are common and would like to hear from them as I dealt with 86-88's maybe 9+ years ago but not an fd. The space in there is just mind-numbing.
Extra sightings. Was told the engine may be recently rebuilt and has good compression(80-90's), engine mount bolts were loose so tightened them up. The LIM has a new gasket as seen from underneath. No a/c, p/s, air pump. Had taken the TB off when checking coils and had some oil in there that I wiped out. Has like a dry sump looking deal on the bottom of gas tank that is capped off as well as a fuel cooler on the back pumper capped as well. Also did the check engine light for codes and cleared up all but a couple including fuel pump relay. There is a relay with wire running to battery in the back, so guessing there may be something there to check as well.
Last edited by Houstonderk; 12-07-15 at 05:26 PM.
12-07-15, 05:49 PM
#2
Rotary Enthusiast
1. See if the A/C is on. If you siwtch A/C on it will turn the fans on. Failing that someone probably (incorrectly) modded them to be on all the time.
2. probably a leak from either the turbo oil feed or drain connections
3. Have you changed or at least cleaned the plugs? Give new plugs & fresh gas a go.
4. I don't think its an "air bleed" issue. If it was your low coolant buzzer would be beeping at you at times. When you say it "gets a bit warm" how warm is that? does the temp keep climbing? How are you gauging that its getting a bit warm? It may be due to the fans running on low, or depending on how much you know about RX7's it may not be that warm at all.
5. Sounds like fuel cut & or secondary injector problem. I would not think its the relay, as if the relay was not working car would not start at all. Im not sure if thats something that would put a stock ECU into limp mode or not.
2. probably a leak from either the turbo oil feed or drain connections
3. Have you changed or at least cleaned the plugs? Give new plugs & fresh gas a go.
4. I don't think its an "air bleed" issue. If it was your low coolant buzzer would be beeping at you at times. When you say it "gets a bit warm" how warm is that? does the temp keep climbing? How are you gauging that its getting a bit warm? It may be due to the fans running on low, or depending on how much you know about RX7's it may not be that warm at all.
5. Sounds like fuel cut & or secondary injector problem. I would not think its the relay, as if the relay was not working car would not start at all. Im not sure if thats something that would put a stock ECU into limp mode or not.
12-07-15, 07:10 PM
#3
1. Good idea, although the a/c got removed not sure if the button is pressed for a/c
2. Will have to find a way to squeeze in there to see better
3. I do still need to get fresh plugs, will get some this week
4. The buzzer went off before I shut it down the first time I got it running and let it idle for a good 20 minutes. That was the first time in almost a year most likely that it ran. I've seen that most don't like the stock gauge, which is what I was watching. It never went above half though and the belt was a bit loose around the pump, so tightened it up.
5. I may try just putting a relay in the empty spot up front and see if the code erases, or at least see what all was modified for this fuel circuit. If it goes through to high rpms when staying out of boost, would that take away the secondary injector issue or is it not based on boost pressure?
I did have to rig up the stock boost sensor as there was a different plug on the wiring, but I did have a diagram so I am sure its the right wires.
2. Will have to find a way to squeeze in there to see better
3. I do still need to get fresh plugs, will get some this week
4. The buzzer went off before I shut it down the first time I got it running and let it idle for a good 20 minutes. That was the first time in almost a year most likely that it ran. I've seen that most don't like the stock gauge, which is what I was watching. It never went above half though and the belt was a bit loose around the pump, so tightened it up.
5. I may try just putting a relay in the empty spot up front and see if the code erases, or at least see what all was modified for this fuel circuit. If it goes through to high rpms when staying out of boost, would that take away the secondary injector issue or is it not based on boost pressure?
I did have to rig up the stock boost sensor as there was a different plug on the wiring, but I did have a diagram so I am sure its the right wires.
12-08-15, 10:24 AM
#5
Okay, so got some nice weather this morning and went at it.
1. A/C button isn't on, checked the front relays and didn't see any extra wiring that would bridge anything.
2. Thought was oil, but did a cooling system pressure check and found about 3 leaks including the hose going to heater core which was leaking onto exhaust so got everything tightened up and no smoke now.
3. Store only had leading so changed those out, but my tard self found that all 4 plugs were loose, so tightened those up.
4. Seems to be holding up now with all the leaks gone.
5. Still have the issue but seems it happens in 3rd gear on, not so much 1st or 2nd.
Did around a block drive and engine codes for fuel pump relay are still on, as well as air pump and metering oil pump. Will have to check the pump code out for sure, but will first clear it and see if the plug had just been undone. I got a video I did and it's running pretty decent for sitting so long. Will upload in a bit.
1. A/C button isn't on, checked the front relays and didn't see any extra wiring that would bridge anything.
2. Thought was oil, but did a cooling system pressure check and found about 3 leaks including the hose going to heater core which was leaking onto exhaust so got everything tightened up and no smoke now.
3. Store only had leading so changed those out, but my tard self found that all 4 plugs were loose, so tightened those up.
4. Seems to be holding up now with all the leaks gone.
5. Still have the issue but seems it happens in 3rd gear on, not so much 1st or 2nd.
Did around a block drive and engine codes for fuel pump relay are still on, as well as air pump and metering oil pump. Will have to check the pump code out for sure, but will first clear it and see if the plug had just been undone. I got a video I did and it's running pretty decent for sitting so long. Will upload in a bit.
Last edited by Houstonderk; 12-08-15 at 10:29 AM.
12-08-15, 11:17 AM
#6
You're getting an air pump CEL because you have no air pump. With all the mods, you probably don't have an OMP either which means you need to premix. Since your car has been modified, and not by you, I would recommend going through everything to see what has been done. Might be best to revert it all back to stock (or near stock), get it running right, and then make the mods you want to make.
You should also run the coldest plugs you can. Either BUR9EQs or BUR9EQPs in all 4 holes. There are colder ones, but those are only necessary for high boost. applications. The 9s can be found locally at auto parts stores, but you have to search for them
You should also run the coldest plugs you can. Either BUR9EQs or BUR9EQPs in all 4 holes. There are colder ones, but those are only necessary for high boost. applications. The 9s can be found locally at auto parts stores, but you have to search for them
12-08-15, 03:47 PM
#7
Well I know for sure the OMP is there and can be seen in the video as well. The first drive I did to put gas in, didn't set it off, but now when driving around the neighborhood, the code pops up. Cleared it and came back, so most likely will take off the upper half of engine to check some other things when dealing with the OMP. Probably get the injectors cleaned and check the hoses in there. Also been contemplating getting a power fc to be able to strip some of those hoses and other things out, but will have to see later this month.
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12-09-15, 07:18 AM
#9
Looks like someone attempted a hack job at a fuel sump. Those look like home depot pipe fittings. I would suggest finding a good used stock fuel tank.
If you are on the stock ecu the "wall" you are hitting is most likely boost cut. You need to either put the stock exhaust back on or upgrade the ecu. If you keep driving like that you will hurt the motor.
The fans are always on because someone probably wired them to switched 12v instead of using the factory 3 speed system. I would go through it and revert it back to stock, replacing any relays that may be faulty.
Agreed that compression in the 80s is barely adequate. Once it falls into the 70s, these cars become difficult to hot start. A good motor should be over 100 psi on all faces. My builds are usually in the 120-130 psi range.
There is a ton of information on here to help you out as well as a whole lot of crap, so you have to sort through it. If you are not comfortable going through the car or want extra piece of mind, there are several specialists available not too far from you. If you want to bring the car to NJ, I'd be more than happy to look it over.
If you are on the stock ecu the "wall" you are hitting is most likely boost cut. You need to either put the stock exhaust back on or upgrade the ecu. If you keep driving like that you will hurt the motor.
The fans are always on because someone probably wired them to switched 12v instead of using the factory 3 speed system. I would go through it and revert it back to stock, replacing any relays that may be faulty.
Agreed that compression in the 80s is barely adequate. Once it falls into the 70s, these cars become difficult to hot start. A good motor should be over 100 psi on all faces. My builds are usually in the 120-130 psi range.
There is a ton of information on here to help you out as well as a whole lot of crap, so you have to sort through it. If you are not comfortable going through the car or want extra piece of mind, there are several specialists available not too far from you. If you want to bring the car to NJ, I'd be more than happy to look it over.
12-09-15, 09:06 AM
#10
I didn't realize how limited the stock ecu was, but can see it probably limiting the engine. I will be taking this weekend to go through the upper end to check over vacuum lines since I have to test the OMP, as well as probably inspecting/sending the injectors to get cleaned. I've only dealt with haltech as an ecu replacement, but have been looking at a power fc recently for this car. It seems besides the long process of updating with the hand controller, it would simplify alot of the things in the engine bay. Been reading through the faqs and had no idea there were a gajillion vacuum lines and solenoids and all the controls for the turbo setup.
12-09-15, 12:19 PM
#11
While the upper is off:
Replace the vacuum hoses and check valves. I use silicone hose from boostcontroller.com and viton check valves from Dale Clark.
Either clean and flow test the fuel injectors and replace the pulsation damper, or go with a new setup like Full Function rails and Injector Dynamics injectors. If you keep the stock setup make sure the fuel recall has be performed. The updated part has a crimp fitting from the primary to secondary fuel rail connection. The old style is a slip on hose and fails. Make sure you replace the fuel injector insulator grommets as well.
Replace the spark plug wires. I like the NGK oem replacement.
Add an FC thermoswitch so the fans come on faster. Not 100% necessary if you upgrade the computer but it will still get the fans on high speed sooner. You still need to go through your fan wiring and relays.
Eliminate the pcv. It doesn't work very well on these cars.
Replace the throttle body coolant hoses or eliminate them all together.
New gaskets for everything you take apart: uim, throttle body, etc.
A Power FC is a good option for a street car, but a Haltech PS1000/Elite or AEM Infinity is a far better ecu. Haltech may be the best choice since you said you are familiar with it.
Replace the vacuum hoses and check valves. I use silicone hose from boostcontroller.com and viton check valves from Dale Clark.
Either clean and flow test the fuel injectors and replace the pulsation damper, or go with a new setup like Full Function rails and Injector Dynamics injectors. If you keep the stock setup make sure the fuel recall has be performed. The updated part has a crimp fitting from the primary to secondary fuel rail connection. The old style is a slip on hose and fails. Make sure you replace the fuel injector insulator grommets as well.
Replace the spark plug wires. I like the NGK oem replacement.
Add an FC thermoswitch so the fans come on faster. Not 100% necessary if you upgrade the computer but it will still get the fans on high speed sooner. You still need to go through your fan wiring and relays.
Eliminate the pcv. It doesn't work very well on these cars.
Replace the throttle body coolant hoses or eliminate them all together.
New gaskets for everything you take apart: uim, throttle body, etc.
A Power FC is a good option for a street car, but a Haltech PS1000/Elite or AEM Infinity is a far better ecu. Haltech may be the best choice since you said you are familiar with it.
Last edited by IRPerformance; 12-09-15 at 12:21 PM.
12-09-15, 04:30 PM
#13
While the upper is off:
Replace the vacuum hoses and check valves. I use silicone hose from boostcontroller.com and viton check valves from Dale Clark.
Either clean and flow test the fuel injectors and replace the pulsation damper, or go with a new setup like Full Function rails and Injector Dynamics injectors. If you keep the stock setup make sure the fuel recall has be performed. The updated part has a crimp fitting from the primary to secondary fuel rail connection. The old style is a slip on hose and fails. Make sure you replace the fuel injector insulator grommets as well.
Replace the spark plug wires. I like the NGK oem replacement.
Add an FC thermoswitch so the fans come on faster. Not 100% necessary if you upgrade the computer but it will still get the fans on high speed sooner. You still need to go through your fan wiring and relays.
Eliminate the pcv. It doesn't work very well on these cars.
Replace the throttle body coolant hoses or eliminate them all together.
New gaskets for everything you take apart: uim, throttle body, etc.
A Power FC is a good option for a street car, but a Haltech PS1000/Elite or AEM Infinity is a far better ecu. Haltech may be the best choice since you said you are familiar with it.
Replace the vacuum hoses and check valves. I use silicone hose from boostcontroller.com and viton check valves from Dale Clark.
Either clean and flow test the fuel injectors and replace the pulsation damper, or go with a new setup like Full Function rails and Injector Dynamics injectors. If you keep the stock setup make sure the fuel recall has be performed. The updated part has a crimp fitting from the primary to secondary fuel rail connection. The old style is a slip on hose and fails. Make sure you replace the fuel injector insulator grommets as well.
Replace the spark plug wires. I like the NGK oem replacement.
Add an FC thermoswitch so the fans come on faster. Not 100% necessary if you upgrade the computer but it will still get the fans on high speed sooner. You still need to go through your fan wiring and relays.
Eliminate the pcv. It doesn't work very well on these cars.
Replace the throttle body coolant hoses or eliminate them all together.
New gaskets for everything you take apart: uim, throttle body, etc.
A Power FC is a good option for a street car, but a Haltech PS1000/Elite or AEM Infinity is a far better ecu. Haltech may be the best choice since you said you are familiar with it.
1 thing I have observed is that with the twin turbos, some controller standalone systems will only work with singles. Anyone notice that with the power fc?
Last edited by Houstonderk; 12-09-15 at 05:09 PM.
12-10-15, 09:07 AM
#14
All the stand alones will work fine with the twins or single. However, the Apexi PFC has the ability to change the rpm in which the secondary turbo transition occurs. The PFC is a little old school but is really simple, has a ton of information about it on this site and is also like getting 10 gauges in 1 as well. I really like them if you plan to stay at 500HP or less.
12-10-15, 12:23 PM
#15
Tested the omp today and failed the stepping motor resistance test so looks like I have to replace that thing. Although having the car running somewhat smooth, tested the cooling system which holds pressure I may just block off th omp and get a power fc when doing this upper manifold work. Never been a fan of telling someone that they put oil with fuel for a car, but would most likely be helpful with engine lubrication.
Last edited by Houstonderk; 12-10-15 at 04:21 PM.
12-12-15, 02:19 PM
#16
Well the power fc is in, and have to say... 98% of the problems are gone now. Of course premixing since the omp shows bad, will stay no to little boost until the wideband gets in and can properly monitor. But right now can start and decent for now. Really is different with the controller as I am used to a laptop, but for now it works.
12-18-15, 02:14 PM
#17
This thing can throw some curve *****. I decided to take a maybe 10 minute drive around the city, drove fine and no stalling. Stayed under 3 psi boost and on the 5.08 base map in power fc. I have a wideband, but the previous bung in the exhaust is right on the turbo so no space and too close so I have to get another one installed later. Long story short, came back home, and have the milky residue in the oil cap area. This is the time for condensation which is what feel like it is due to no overheating, and it not being in the oil dipstick area, just the cap. I have some videos I took as after putting the coolant bleeder on as well as another comp check when warmed up.
The main things that are showing is, not much with cooling system, but the comp numbers were only at 35. I have done comp tests before,(throttle open, I even tried with elbow off) when picked up it was around 70's after sitting for almost a year. I feel like maybe the tester is bad as the only thing showing that low comp would be the idle if at all. It seems to run fine with the bit rough idle. Start up with no problem as well.
Let me know what you think. I'm basically trying to find the health of this motor clearly before starting other projects on this car.
The main things that are showing is, not much with cooling system, but the comp numbers were only at 35. I have done comp tests before,(throttle open, I even tried with elbow off) when picked up it was around 70's after sitting for almost a year. I feel like maybe the tester is bad as the only thing showing that low comp would be the idle if at all. It seems to run fine with the bit rough idle. Start up with no problem as well.
Let me know what you think. I'm basically trying to find the health of this motor clearly before starting other projects on this car.
12-18-15, 02:57 PM
#18
The milky residue is water. The question is it from condensation or blown water seals. If you are not blowing white smoke and not getting any bubbles in your lisle funnel, it may just be condensation, esp if you haven't run it much.
I would recommend changing your coolant. It looks pretty nasty. You may need to flush it a couple times to get it clean (and make sure you drain the coolant in the block). Also, you should change your oil if you haven't yet and esp if you have water in it
I would recommend changing your coolant. It looks pretty nasty. You may need to flush it a couple times to get it clean (and make sure you drain the coolant in the block). Also, you should change your oil if you haven't yet and esp if you have water in it
12-18-15, 03:02 PM
#19
I will be changing most, if not all fluids but just can't get over the engine. Do I change everything just to have to drain a blown/weak engine is the main point I have. Although if it's something that needs to be done to test the engine properly, then I will have to do it.
12-19-15, 09:24 AM
#20
Original Gangster/Rotary!
iTrader: (213)
Honestly, without a proper Rotary Compression tester you're not going to get really accurate readings.
I'd recommend replacing the OMP with a nice low mile unit..... I happen to have a few of them sitting around if you need one
Each application is different---- my single turbo 'track car' (2016 anyway, lol) has blocked off OMP with the orifice properly welded up. My 1100 mile MB garage queen still runs it.
You're better off using the OMP along with premix IMO, and note that pretty much every OMP block off plate leads to an oil leak due to there being not much sealing real estate around the plate. Not a fun situation. If you do decide to use a BOP make damn sure you seal it well.
I'd recommend replacing the OMP with a nice low mile unit..... I happen to have a few of them sitting around if you need one
Each application is different---- my single turbo 'track car' (2016 anyway, lol) has blocked off OMP with the orifice properly welded up. My 1100 mile MB garage queen still runs it.
You're better off using the OMP along with premix IMO, and note that pretty much every OMP block off plate leads to an oil leak due to there being not much sealing real estate around the plate. Not a fun situation. If you do decide to use a BOP make damn sure you seal it well.
12-19-15, 06:00 PM
#21
Guess i'll just drive it around and maybe put some MMO in there to burn out carbon. Might be some carbon sticking the seals since it sat for a year. Got my gauges put in, and it idles with 12 or so vacuum at 1000 rpm which seems a bit low. Got to test out the map in power fc since I have my wideband in and it seems to be a pretty good map for my setup. Went up to around 5 psi boost and handled nice.
Rattling noise is the hood, for some reason it sits a bit off the rubber mounts so I have to either raise them or find some larger.
Rattling noise is the hood, for some reason it sits a bit off the rubber mounts so I have to either raise them or find some larger.
12-21-15, 01:34 PM
#22
Seems to be getting better with spot tunes and just driving. Got to stretch the ol legs today after finding a mount for the front plate. Got to tune/fix I believe is the dashpot. Basically when it's in high rev and then coming out of gear, the rpms drop to below the 1000 or so rpm idle and can die at times so i'll just pop the clutch to start back up.
Last edited by Houstonderk; 12-21-15 at 01:46 PM.
01-01-16, 05:05 PM
#23
So an interesting find I had today that I have to figure more into. Basically the idle has still been bumpy, but being I have the power fc I've been 'safely' going through the settings and found that altering the ign/inj setting which is a temporary thing that resets with key off. I altered the Lead timing to -20 or so from the 0 it had and the idle and driving felt almost perfect and idled nice. Gonna take a new video in the morning, but based on that and using the base map in power fc, does this mean something ignition wise could be installed wrong? I'm used to the fc which has a CAS, but reading the fd doesnt have any adjustments and the pulley only goes one way.
01-09-16, 04:33 PM
#24
Now at a crossroads... Decided to go single and that also helps with doing all the blockoff plates I'm putting on. Got down to the the basics today and looks very easy to just pull the motor for a rebuild(just have to deal with the cost). Of course as mentioned before, it was mentioned it may already be a rebuild. Ran at around 11-13 vacuum at 900 rpms with a bit rough idle, and 80 or so all around on compression. I know they say a rebuild can have low comp if reused housings with new seals so there is that as well. There were a lot of loose vacuum lines in the rats nest area that could have been a vacuum leak and some on the LIM were a larger size than the nipple so just slide off and on.
Maybe I'm answering my own question and should just progress with the new single and hope that there was some leaks before.
Is there a way to tell if the motor was ported without having to take the engine apart?
Another thing is holy bejesus the LIM vacuum ports! There are over 10 of them! I have heard of the excessive LIM and nice price for what it is, but it's still up there.
Maybe I'm answering my own question and should just progress with the new single and hope that there was some leaks before.
Is there a way to tell if the motor was ported without having to take the engine apart?
Another thing is holy bejesus the LIM vacuum ports! There are over 10 of them! I have heard of the excessive LIM and nice price for what it is, but it's still up there.