Engine Stall

[GTP091]

Sometimes my engine will stall when Im stopped or taking a low speed corner with my foot off the throttle. My car's RPM's also sometimes dips down up to 200 RPM and stumbles when stopped and in gear. If I roll in neutral there is no miss but as soon as the car stops when in gear it misses real bad. It has a low speed miss almost all the time anyone have any ideas?? Once in awhile it will pull code 42 which is check igniton control wiring. Before my initial problem of no starting (crank sensor) it ran amazing. After my Crank Sensor was replaced my timing was way off (crank sensor wires reversed) so I replaced a long list of parts to fix that. Now the car runs great with lots of power and pulls strong up to redline. But now has the above problem when idling when in gear and stopped.

Roughly last to first:

Reversed CS wiring
Cam Timing redone (by a shop with experience, has more power than before),
IAC valve,
EEPROM
ECU
Plugwires,
Coils, (MSD)
Replaced all Intake gaskets (myself first - then the shop while doing my timing),
Repalced Fuel injector O-rings,
ICM,
CS sensor,
Fuel Filter,

I have relocated my ICM to where the batterty usually is (battery in trunk). The ICM wiring has been tested a dozen times. Do you guys have any ideas??

I have not replaced the o2 sensor but I don't think it would be the problem.

[Juglenaut]

Reverse the Crank position sensor wires, has help one person before yet I don't know why. But seem you experienced differently hmmm I am still boggled by this.


Would not hurt to test fuel pressure through rpm.

Check resistance or some call impedance of the injectors.

Use Standard brand ICM coils not MSD.

[napatiger]

CrankPS should not make a difference after the car is started.
CrankPS wires just need to be wound up right, and the car will start.
Then the CamPS will take over timing of injectors.

But for the 'loop' at idle speeds, hmmmm.
I had that same problem before the rebuild....But with so much done, I don't know what actual part fixed it.

I actually had a problem with the Positive wire that goes from the Alt to Starter to Post. Seems like bad ground and/or low rpm+poor positive to the alt/starter. I like separate new wires to each, not bridged.

Maybe a vacuum problem.or LIM gasket.

You already checked compression?

I did change my O2 sensor.

Looks like you changed alot of the Electronic stuff already. Did you change most of it from necessity or because you wanted MSD? reason I ask is b/c the same things breakdown with those parts such as your wiring harness. I suspect rewire of ignition stuff. Some low gauge wires were used and with much movement will cause shorts or bad grounds. I would rewire grounds first.

[grandprixgtp_91]

Here

http://60degreev6.com/showthread.php?t=33539

and these cars will not run with the crank sensor wires reversed, i know from experience, it will backfire and not start. , and you cant reverse the connector, you actually would have to cut and splice the wires, but i had a problem with my crank sensor, the connetor pins were bent and when the car warmed up it would stall out because it would lose contact, but it did it even with the gas pedal being applied, and then it wouldnt start back up until it was cold. but read the post i copied into here thats probably it. phantom stalling, my car used to do it alot.

Jake

[GTP091]

The Shop that did my timing to fix my engine misfire - no power problem, tested the fuel system completely, and the pressure was perfect. I also replaced the fuel filter when I started replacing parts to fix the no power problem I had. The original problem I had is the car would not start. So I started replacing parts. Turns out the crank sensor was bad, so I decided to replace the entire wire and harness while I was at it. That's why I ended up with the wires reversed and spent well over $2000 fixing that. The shop that checked out that problem blamed it on timing but they missed the CSP sensor wiring (5 cents of solder and shrink wrap fixed it).

I know my issue is electrical because I pull code 42 which is {check ICM (replaced) or ICM wiring circuit}. Do you guys know where I can get a new harness for the ICM? GM does not have this part.

[jdellinger1980]

Here

http://60degreev6.com/showthread.php?t=33539

and these cars will not run with the crank sensor wires reversed, i know from experience, it will backfire and not start. , and you cant reverse the connector, you actually would have to cut and splice the wires, but i had a problem with my crank sensor, the connetor pins were bent and when the car warmed up it would stall out because it would lose contact, but it did it even with the gas pedal being applied, and then it wouldnt start back up until it was cold. but read the post i copied into here thats probably it. phantom stalling, my car used to do it alot.

Jake

I just read your post and I tryed to follow that link and it says page not found. I really need to know something about this because I swaer this is my problem on my 93 z34 please help.

[RedZMonte]

I have heard alot of bad things about the MSD coils on our cars... try putting stockers back in, if the problem doesnt go away, return them... its a free diag.... that is where i would start.