91 Z34 still Sick, but now have free scan

[robertisaar]

there is a limp mode in the PCM, it forces the transaxle into 3rd gear at all times(i might have read moving the shifter would cause 2nd to become available?), and the fuel and spark is run off of two NETRES ICs on the MEMCAL that are VERY conservative in advance and very rich in fueling. one of the cooling fans are supposd to kick on and if it was in limp mode, you would NOT be able to access the datastream either.

[portsider44]

Well this car has just about got me beat. Spent another $30 bucks to replace the weak coil on 3/6 and got it installed. Car started up and idled good. Pulled each of the 3 plug wires and all are getting good white/blue spark that will jump to metal upto 1 inch away.

Now with front wheels in air tires still move while in neutral. Trans still not going into low & will not go into 2nd when in OD or D, but will when manual shift to 2nd. However with wheels up in air I started in 2nd went took rpms up to 2000 then shift through gears holding rpm steady, which would make mph increase. Car ran fine & did not stalled.

So at this point I am thinking coil might have fixed the stall problem & now maybe all I need to do is figure out the transmission (maybe it in fail safe, can this be seen on tuner pro)? Turn car off lower it off jack stands restart & get ready for a test dive. Back out of driveway put into 2nd gear go to give it gas & it dies. Now restart & go to pull back into the driveway, where it dies & will not restart.

Check for spark in front 3 & all have good spark, however it will not start. One spray of starting fluid & it starts idles rough at first but then settles into good idle. Which leads me to think my problem is lack of fuel but my fuel pressure looks good, could it be the computer shutting off the injectors? Anyway to see this on tuner pro?

I don't get why it will run up to speed with wheels off the ground but can't even get out of the driveway with wheels on the ground? I know you thought ECM might be the issue do you think that is still the case?

Right now I am more interested of getting it fixed just so I can say I fixed it. Between the new plugs, new radiator, crank position sensor, fuel pressure reg, coil, o2 sensor, & way too many hours spent messing with it I wish I would've just punted. Amazing how pride can get in the way of things.

[robertisaar]

the tires moving is normal, think about it: the engine is spinning the torque convertor, which drives the pump in the transaxle, which moves fluid around via the valve body. there may be a clutch JUST making contact, but more likely it's just due to the movement of the trans fluid, mine did the same thing a LONG time back(around 140K) and no problems.

the ECM shouldn't be cutting the injectors, there's no reason to in this situation.

i wonder if the ECM thinks the 2nd gear start switch is engaged....(even if you don't have the switch, your car is still wired for it). it is something you can see in tunerpro, but not with the exported CSV files, we would need to have the raw ADL file for that.

[portsider44]

Robert what would your suggestion be for my next step here?

Any way to test the fuel pump before the regulator? Could FPR be holding up fuel flow in order to maintain pressure? So my FPR guage looks right but the amount of fuel is off?

If the ECM was shutting off the fuel pump that would be seen in tuner pro under FP volts right?

Also on tuner pro only thing I can remember seeing about transmission is gears solenoid A & B. What should they show while in park & while in OD, D, 2, 1?

Also if what all year models of ECM will work might look at getting a junk yard one to try. If I knew the ECM was the problem I have no problem spending $$ to replace, but I can not afford to keep throwing parts & money at this thing.

[portsider44]

tuner pro 7.zip

TUner pro from this morning, went from cold start (47 degrees outside) to test drive in front of house going couple hunfred feet & then u turn as I didnt want to get too far from house. On test drive had no power still trying to start in 3rd, shifting to low only gets 2nd.

Made couple of passed then died as pulling into driveway. Did restart & ran in driveway at various RPMS & even ran a/c to test charging system. Shows slight volt drop but not bad. So I think the the battery & alternator are ok. Only volt issue I see is during start load.

Only thing that looked odd on tuner pro was sample 200 Rich/Lean going from 253 to 1. If this caused by going into open loop? Also Target Airfolw vs engine airflow always looks off, but not sure if that is an issue.

Only thing I know for sure at this point is that of all the stuff replaced the o2 sensor did need to be replaced.

Couple my transmission issues be causing my problem? What items would cause trans into fail safe?

See if you can see anything that I missed on tuner pro, also if the adls file would help just let me know how to get it to you, as its not an approved file to upload.

[robertisaar]

you can ZIP the ADL file, then upload it.

the shift solenoids will only change when the PCM commands them to change(assuming they function correctly)... 1st gear is both on, 2nd gear is just B, 3rd gear is none, 4th gear is A and B.

[portsider44]

SO here it is I dont see the solenoid changing at all even when in gear. Also during my short test drive o2 got in 800-900 range doesnt that mean its lean? Meaning it could be a fuel supply issue?

[robertisaar]

O2 at 800-900 means rich as hell. the way narrowbands work is you'll see it swinging around 450mV, going from ~200 to ~700mV constantly due to the ECM constantly commanding slightly rich, then slightly lean, then repeating the process over and over.

and you know you have a MAT low error? that SHOULDN'T be causing this issue, since heatsoak doesn't really have time to take effect, but it would be a good idea to see why it's happening.

also, the shift solenoids are indicating that the PCM is TRYING to engage first gear... for some reason, it can't. whether that's because of an internal trans issue, shift solenoids acting funny, chewed wiring, or the PCM itself is junk(rare but it happens)...

[portsider44]

[QUOTE=robertisaar;430259]
and you know you have a MAT low error? that SHOULDN'T be causing this issue, since heatsoak doesn't really have time to take effect, but it would be a good idea to see why it's happening.
QUOTE]

No I didn't know I had a low error, please explain? Too me the reading looked right according to conditions. I would think if it was low error it would read 55 degrees when it 80 degrees outside. In this case it was in the upper forties outside & at start up the MAT was 55.94 & rose to 59.9 as the car warmed up. Plus the MAT & coolant start temp where close (57.2 vs 55.94).

[robertisaar]

i don't know why it had that error, but it did... the temps did seem believable.

try clearing the codes when you're scanning or logging by using the quick-commands in the ALDL Setup menu. if it goes away and stays away, it may have been a fluke. if it comes back, then the reported MAT value may or may not be real.

[portsider44]

I didnt notice it had thrown a code on the tuner pro, I bet it was a store code from replacement of the coil pack. I started the car before I had the airbox back on & the MAT was disconnected. Which caused the ses light to come on but on next restart with everything back together the ses went off.

I will clear the code on my next run. Go to spend some time on the car today, maybe I will get luckly & get this thing figured out.

[portsider44]

Well I spent some more time on the car today. Mainly looking for loose, bare or some type of wiring issues. Including removing & cleaning up all ground wires. All places that went to painted metal, I took all the paint off & got down to bare metal. I did find one wire that was broke or cut. It was the purple wire into the transmission connector underneath the exhaust cross over, which I repaired.

Couldnt get it started at times with out using starting fluid. Starting to think I could have a fuel problem. One thing I noticed after car would run & then die, depressing the schrader valve on fuel rail didnt result in much gas being expelled & didnt really seem like it was pressurize at 38lbs.

My harbor frieght us general fuel pressure gauge still shows I have 38-41lbs of pressure. Which doesnt make since with my thoughts on fuel system issue.

I am open for any suggestions or

[Schurkey]

One thing I noticed after car would run & then die, depressing the schrader valve on fuel rail didnt result in much gas being expelled & didnt really seem like it was pressurize at 38lbs.

That's EXACTLY how my '93 acted for the last hundred and fifty miles before I had the fuel pump replaced, and why I asked you what your fuel pressure was in an earlier post.

3. What is your fuel pressure when the engine dies? I don't see a fuel trim column in your excell sheet...
...Your description of this problem is sounding a lot like what happened to my '93 Lumina when the fuel pump was on it's last legs--no power, engine dies, sometimes restarts easily--sometimes not.

The spooky thing was that it ran pretty good at a 60--70 mile per hour cruise, but had NO power, stalled, and would hardly re-start at lower speed. That last 150 miles took about eight hours; every time it stalled I sat at the side of the road for half-an-hour or more trying to get it to re-start--and generally the fuel schrader valve showed me no love.

I'd just LOVE to see an oscilloscope pattern of your fuel pump current draw.

[portsider44]

Wish me luck going to take another run at the car today. Going to make a run through the basics before I spend the $$ on a fuel pump.

Main reason I have my doubts is that this thing has really been flakey & I think you could drop alot of $$ throwing parts at before you find the cause. To me the fuel rail not having much gas or pressure in it after it dies could be fuel pump or it could be a bad injector.

So right now I am pretty sure it a fuel problem, I just need to figure out if its?

Power to Fuel Pump, which I doubt as my tuner pro shows good FP volts.

Fuel Pump realy, I have cleaned every thing up & since I have food FP volts it must be working. However when I put 12v to the FP over ride (loose connector on FP relay. It doesnt seem to work???

Fuel Pump (it shows good pressure on the but I wonder it it doesn;t have the volume to keep up with engine needs

Bad Injector causing a short in the injector system causing the ecm to cut power to injector, or just a stuck injector free flowing & starving the other?

[portsider44]

Well I think I have found the issue.

Test EGR & all made clicking sound with car off. Started up & let warm up. At this point I have a noid light on number 6 injector & it is flickering. At idle dim, as RPMS increase it get brighter. Now with car warm not sure if open or close as I didnt have computer hooked up. Touching Solenoid 1 & 2 would drop vacuum & RPMs would drop, also as vac dropped fuel press would go up. Holding on 1&2 would not cause a stall. On solenoid 3 guick touch would cause large vac drop & you could hear it sucking vac??? Just like if you unlpugged a vac line. Hold it on #3 & it would stall.

Now pulled upper intake off & grab multimeter to test injectors. 2-4-6 all at 12.6-12.7. Now 1 is 12.7, 3 is 12.8 & 5 is 0.9

SO looks like I need another injector & hope it will fix all my ills.

Should I hear vacuum when #3 (large) egr solenoid is ingaged?

What all model of fuel injector will work. Looking at ebay looks like 3.1 not the same & 94 & up 3.4 is also not the same.