danec020

I am trying to work out the last kink in my rebuild and it is somewhat similar to 3800rpm hesitation. I believe it is due to timing. Basically when I am giving the car anything over 40% Throttle and it runs fine up to 4k EXACTLY every gear every time. When it hits 4krpm its like something is stoping its acceleration but the rpms still raise slowly. I can smell fuel so I am believing it is recieving too much fuel at this point, but there is no poping like running rich... Just a major loss of power. Now if I do anything under 40% throttle it goes through fine, no problems at all. I also have a small miss every now and then when I idle.

Now the reason I believe it is timing related. I have stabbed the CAS correctly (done a lot of searching on subject and have no doubts its right :P, and yes I pulled the top cover off and watched the gear to make sure I could reposition it). So the Leading mark is lined up and the cas is stabbed... Now the timing light shows the leading mark is fine, but when I switch it to the T1 it is not even anywhere near the pin. The same thing happens with the leading if I time the Trailing first.

Last reason I believe it is timing... I figured I would play with settings since the car ran well besides that one problem. I noticed if I turned the CAS Clockwise all the way it lost the miss it had when idling and had a little more speed, but still had the same 4k problem, but not it would go in and out kinda like hesitation coming and going. But when I turned it counterclockwise all the way, the miss came back and the 4krpm happened no matter how much throttle I gave it. I babied it, maybe 4% Throttle trying to slowly go past 4k and it wouldnt even do that.

So what do you guys believe this issue could be? Ignition cables is the only thing I could think of, or the actual CAS itself... The ignition cables are new, atleast what I was told by the owner who sold it to me a year ago.

Other things not mentioned: CAS does adjust the timing when I accelerate and decel. The car is S4 TII 10th AE, has emissions removed, and TB MOD, Intake, Fulle RB Exhaust, Walbro Fuel Pump.

danec020

Ok this problem is really killing me guys. Anyhelp will be appreciated. To sum it up, I been messing with timing a lot and have gotten the car to run a little better but still having major issues. I have put a timing light on L1 and time the car, but when i checked T1 or T2 the timing wasn't even close. I couldn't even see the mark. But all the sudden my idle changed and it was on time! So I figured it might have been a electrical problem, so I moved wires around and nothing happened, the timing stayed perfect. So I gave it a hair of throttle and as soon as that happened it went back to being way off. If I waited for a little bit you could hear the idle change again and it was back on time...

Naturally I figured I would check the CAS, Ignitors, and Ignition coils. The CAS has 191ohm resistance, the Ignitors packs has .3ohm resistance, and the coils were new when I bought the car and still look to be in great shape...

So what should I look for now? What could cause this? Plugs are also new BTW.

Any help would be appreciated, because of now the car can't accelerate past 4krpm unless I give it only 20% Throttle.

Dane

Smoken'

iTrader: (1)

It sounds like you might have a secondary injector problem. Have you confirmed that they are working? Will the car rev over 4k while sitting still?

As for the timing, just the slightest bit of rpm change will cause your timing marks to move. This is normal, ignition timing advances when the rpm rises. In order to get the timing perfect, you need to get it to idle right.

danec020

Sorry I should have been more clear. The timing isn't going off while I am reving... It advances like it should and when it goes back down to idle the timing is so far off I can't see the notch and the car idles at about 700rpm. Maybe a minute later or 5 seconds, or never (randomly) the idle will change and it will fall to 450rpms and purr like a kitten and the timing marks are where it should be. Then as soon as i tap the gas and let it come down to idle the same thing happens. I know the spark advances as the rpms advance. The car can redline in all gears if I give it 20% throttle the whole way, and it will creep to redline. If I do more than that its like it hits a wall at 4Krpms and the rpms climb and I go nowhere. It will redline but the car sounds like it is so rich the spark is being put out. There is no backfiring though...

As for the settings, the TPS is set at 1Kohm like it should be, the car is pretty much stock so shouldnt need to be higher or lower.. Besides that my injectors have been cleaned and flow charted by witch hunter performance. Today I was testing it alot and I noticed 1st gear is fine all the way up to redline no matter how much throttle I give it.. But right now I think I should work with the timing issue rather than push it to redline . I need it to stay timed all the time, advance like it should, and go back down to timed...

Please Rotary gods, as you can see I been dealing with this problem for well over 2 months heh.

Thanks
Dane

danec020

Ok bump/more info. I checked my boost pressure sensor to see if that could be the culprit because awhile back I was having issues with a FCD. I just got done checking it and it tested good and just incase I had swapped my friends pressure sensor on that was the same model number N318. And the same results happens.

I noticed this wall isn't really related to throttle as much as it is boost. As long as I am not boosting into 4krpm+ it wont hit the "wall" if I am boosting while exceeding 4Krpm it has the problem I mentioned above. So I started reading the FSM and looking at everything dealing with boost and noticed there is a Solenoid resistor.

******EDITED I FOUND ANSWER TO THAT**** That is the solenoid resistor for the injectors and is only needed on Pre 87.5 engines for those wondering as well.

My problem is still here though

Thanks
Dane

RRTEC

iTrader: (13)

This might sound dumb, but have you warmed the car up to operating temp before attempting to time it? Try regrounding the main ecu harness..

danec020

Thanks for the reply. Yes the car was warmed fully before timing, right now the only thing I can think of is a ground issue, but it idles at 600rpm solid no bouncing and drives fine as long as I don't boost past 4krpm. So the ground issue doesn't seem to be it but you never know, I am going to make new grounds for everything. If it doesnt fix it, it will atleast be a better ground setup .

Thanks for the help,
Dane

Smoken'

iTrader: (1)

Try Re-grounding your ECU. I was having some hesitation as well when hitting boost. All i did was run a 12 guage wire to the body of the car from the ground wires in the ECU harness. All of the grounds run to one wire and then all the way back to the top of the engine. The hesitation wasn't nearly as noticalble after i did this. My hesitation wasn't nearly as bad as what you have described however, it more of a 3800 hesitation.

HAILERS

The secondarys are not coming online. It's as simple as that.

Primarys alone will get you to red line as long as there is no LOAD while accelerating.

If under LOAD while accelerating, the boost sensor tells the ECU to activate the secondary injectors around 3800rpm. When that happens ON A NORMAL RX, the duty cycle for the primarys gets cut in half and the secondarys will have the same duty cycle as the primarys.

So, what is happening, is when accelerating under LOAD, the fuel for the primarys gets cut in half at 3800rpm, but .....whoops, for some reason the secondarys did not come on line.

So, you see what happened. The fuel you were using before 3800rpm got cut in half causing the car to hit a brick wall.

Under light acceleration the car goes to redline because there is no LOAD at 3700rpm to speak of, so the primarys fuel DOES NOT get cut in half and the secondarys stay closed as they should.

I'd suggest the secondarys are the problem or the drivers for the secondarys in the ECU are the problem. Or the wiring is screwed up for the secondarys.

I'd put a meter on the ECU wire for a given secondary injector and go for a drive. The voltage should show Battery voltage until you hit 3600 rpm under LOAD where upon the voltage should drop dramatically from as and example 12vdcc to maybe about 7volts dc, as long as your under load accelerating

IF you put a meter on either of the secondary wires at the ECU and you don't see battery voltage, ya 'all have a wiring problem. Key just has to be ON when doing this. Engine does not have to be running. Neg lead of the meter on a known ground and backprobe the secondary wire at the ECU plug.

Or you could have some HUGE secondary injectors and when hitting 3800rpm the secondarys are coming online and bogging the darn engine down with toooooo much fuel.

I make stuff up as I go along. Bye.

danec020

Thanks HAILERS for the input. I actually thought of checking the secondaries but didn't know of a good way to do it, now I do. But what do you think is causing the timing issue? (ie what could cause it to randomly drop into timing, and stay there untill i give it a little throttle and then when going back to idle it is off timed untill I let it sit for awhile?)

Thanks
Dane

danec020

Ok this is what I got. With the key turned to the ON position all Injectors including the primary had a 11.5dcV. But when I turned the car on they all read 0.1dcV. When I would rev the primaries would drop to 0dcV. The secondaries would just hold the .1dcV. So what does it sound like? It seems really bad but my idle is a strong 500rpm, no bouncing or anything... Anyone can help this idiot know what these readings mean?

Thanks
Dane

danec020

I just got back from doing some test drives as well with a Analog meter to make sure my digi meter was messing up. The analog produced the same results but since it doesn't have negatives it showed it droping below 0. The engine comes on all of them go to .1dcv and after searching a lot I am assuming that is cause the ecu is grounding them and will unground it as it needs to inject fuel? Well on my test run I boosted it and looked at the secondaries voltage and as soon as they kicked in they droped below 0dcV. I couldnt get too accurate of a read on the primaries but they looked like they were doing similar results.

So does this mean I am ok? And my problem can be elsewhere besides the ECU signal side?

Thanks
Dane

PS: Forgot to mention above the TPS is a brand new one from mazda, so please someone don't post saying it sounds like a TPS issue :P. It is set to 1kohm and is working fine and all signals are fine .

danec020

Bah I am an idiot. I didnt know you couldnt use the ECU ground wire as a ground source. I just did another trip using a ground off the body and totall different results. The Injectors all get 12dcV with the engine on, as I accelerate the primaries drop to about 7dcV. When I hit boost at 3800rpm the secondaries drop from 12dcV to about 7~10ish depending on how much throttle I was giving and thats when it bogs... So the signals are working correctly it seems but yet I still have the bogging issue. I am going to pull the UIM and see if the injector caps are securely on the secondaries..

Is there anything else I should try or look at first?

Thanks a ton Hailers, I feel like I am making a little more progress atleast.

Thanks
Dane

HAILERS

Well, if you see approx 12v on the secondary injectors and they don't drop from that value UNTIL you hit 3800rpm under LOAD. then the injector plugs are definetly ON. Because the 12v your looking at on the secondarys wire at the ECU COMES FROM THE INJECTORs.

The ECU just puts a ground on the injectors to make them open/shut. It does that in milli seconds. Ground on/off in milli seconds.

So, from your description it sounds like the secondarys are coming online when they should. So I'm at a loss as to why your engine boggs down at 3800rpm under LOAD.

The only thing that comes to mind, is if the secondarys were huge as in 720cc or something like that on a not too heavily moded engine. Too much fuel would cause a large bogg.

Another angle is to drive along with a fuel gauge tied to your windshield wipers and watch the fuel pressue as you drive. It'll be somewhere around 30 at idle and while driving around 37-39. When you go into boost it should rise a psi for each psi of boost pressure. I've seen as much as 49psi on a relatively stock car under full boost. Make sure you have good hose connections on the fuel gauge when doing this.

I never used the engine ground wires for a meter ground. I'm not sure why that did not work for you. Do this. Engine off. Key out. Put one lead on that chassis ground you have been using and then backprobe any of the ground wires on the ECU. You might just pull the small plug off the ECU and gain better accesss to the PLUG ground wires. Should be 3A, 3g and 2R. I wouldn't expect more than one ohm or so for a ohm reading on the meter.

Don't do this with the key to ON and the plug on the ECU. It'll confuse the issue.

Just in case you missed it, the 12vdc for the injectors comes from the EGI INJ fuse in the engine bay, passes thru the Main Relay, goes to the solenoid resistor package on early cars, then goes to a pin on each injector, thru the injector to the individual wire on small plug of the ECU. There the ECU puts a momentary gnd on the injector wire to open/shut it. That's why I say the injector plugs are on the injectors.

You might see if the outer set of throttle plates on the throttle body are opening when the throttle is full open. You'd have to look inside to see that.

Smoken'

iTrader: (1)

Hailers, if the filters were clogged in the socondary injectors, wouldn't that cause the voltage to be ok at the ECU, but no fuel to the engine? Just thought i would ask....

Dane, have you ever had this car running? IF you have had it for awhile, did you put different injectors in, or anything like that.

danec020

******SKIP THIS PART IF YOU JUST WANT TO KNOW WHAT ELSE I ELIMINATED AS A PROBLEM********
The car runs, it is my daily driver. As stated above the injecters were cleaned and flowcharted by witch hunters performance and are stock. The car idles at 700 when the timing decides to be off, and 450 when it decides to be on... It doesnt bounce between them, its either 700 and steady as a rock, or 450 and steady. As stated earlier I can drive it without boost and redline it, I can redline it in neutral, I can redline it while giving it boost but once I hit 4krpm I hit this "wall" and lose almost all power all the way up to redline. It sounds muffled almost like if a it is dumping too much fuel or if you had a IC piping leak (without the backfiring). Really dont know of any way to describe it besides that.

My main concern is the timing, because the car is never timed when driving it always goes out of time. It will only sometimes be on time when its idling (it randomly does it when i dont mess with the throttle)...
************************************************** *****************

Ok Back to progress report. I just swaped AFM, Boost Pressure Sensor, and Knock Sensor with my friends S4TII (I checked all serial numbers to make sure they were the same and they were). None of them helped, so I geuss that eliminates those as well since his car runs perfect.

Thanks again everyone, I am killing myself trying to figure this out and have put tons of hours into it and getting really depressed lol. I can't possably think of anything else related to fuel/timing to check.

Hailers I have a new Walbro 255, I think the Fuel pressure should be ok, but your thinking maybe FPR?

Thanks,
Dane

danec020

Just checked the Throttle plates, they seem to be working fine. I did the TB Mod so I have no secondary plates, if that was the one that you though might been sticking...

Could a missing Dashpot, or something I could have taken off on the TB Mod I wasnt spose to cause this?

I think I am going to just going to get a 12pack and sit next to her and drink and try to convience her to run right. :P

Dane

HAILERS

I wasn''t thinking fpr so much. But you might idle the engine and pull the vac line off the fpr and make sure your getting vacuum at it. EVen without the fpr raising the fuel pressure I'd a guessed that you'd have to be past thirty eight hundered before it showed any effect. My guess only. No practical experience on that one.

Someone mentioned the ECU grounds and I passed over that one. I would pull the ECU small plug off and check at the plug, the two black ground wires and make sure that they read about a ohm or less to ground. That caught my eye where you said you used them as your ground for the meter and it did not work right. But later used a chassis gnd and all was well.

Good deal on the swapping parts. YOur parts work in his car?

Yes, if the outer plates are gone forget what I said about them. Damper? No. When under throttle they don't touch so that isn't it.

A last resort is, IF your secondarys are the same as your primarys, swap them out. A bit of a pain. IF they are larger, then don't swap.

Got a SAFC or something like that messing things up????

I've run out of reasonable things to look at. Not fuel cut is it? I think you said no earlier. Got a FCD I think you said. Wonder if it's working if you have one. Might try disconnecting it then put the pressure sensor plug back on the sensor and go for a drive.

OR a little better, try this. Pull the vacuum line off the boost sensor and plug the vacuum line. Go for a drive. Now anytime you reach 3800 the secondarys will come on line. See if the car drives different. The FCD and ECU will never see a pressure high enough for fuel cut and this should eliminate fuel cut.

About the timing. Have you friend take the thin black metal plate off his CAS. Have him put the pulley on the LEAD timing mark. Now compare your CAS to his with your CAS top off. They should be the same especially if his car runs good. Look where the two gears on the top of the cas match the coils in the cas. Two teeth on top and there are 24 teeth on the bottom when looking inside the top of the cas.

Anyway, make your cas look like his. You really should get a timing light for this but if his car runs good the way his cas is then yours should also.

Got your Trail sparkplug wires crossed???? Had to ask. Ran out of ideas.

HAILERS

Got a blowoff valve dumping at around 3800?

danec020

Thanks for the info, I am going to work on regrounding the ECU I think and see if that is my problem. I just picked up a timing light and checked my timing as well. My timing marks are ok at idle, but when I accelerate they advance so quickly that I can't even see where the marks went. As for the pressure sensor I checked voltage on the ecu and it read 2.5v. So it was good, I am currently running no FCD but I am under 8lbs of boost and I get this problem at even 2lbs of boost. So Not fuel cut. I am thinking it is the grounds now because I would have thought the ECU wire ground would have worked as well as the chasis.

What is wierd is it works with the KEY on ON. I get 11.5 volts using the ECU Ground, but ONCE IT STARTS the voltage drops to .2 mV (yes mV). So why would it be ok with it ON and not when started? Both should be using battery power and I don't understand how it would do that...

Thanks, and yes all my parts worked on his as well.
Dane

danec020

Well I want to thank everyone for their help and support on my annoying issue. I think I have it all figured out now and I am pretty upset with Witchhunter now . I spent all last night checking every ground to make sure I had no resistance and after hours of work I successfully checked them all and they all were perfect. Then I checked all sensor, all perfect. So this morning I decided I would swap my injectors since they are all 550s. Low and behold, when I started the car it started up, and started shaking and if I gave it gas it would shake worse. If I didnt give it gas it would die. So I am assuming that means one of my secondaries injectors are stuck shut. Now the question is how can I test it safely and quickly so I can go get more injectors. And if I decide to get 720s instead, should I have rtek or Safc for it?? Or can the stock ECU handle them if I adjust timing/tps/ect?

Thanks again guys...
Dane

PS: To witch hunters defense I had them clean them over a year ago now, but I put them in the day I got them back and started driving on them. I had just rebuilt the engine and was doing the breakin for 1500 miles without boost. Since I only drove it on weekends it made the breakin procedure last a long time, thus I didn't know they were stuck in my warranty time frame .