SLOVED!!! ANY Ideas?? Spark / Ignition Cutting out

[ct3155]

Sweet! Yeah let me know. I'll take mine off and give it a real good look at.... Maybe I screwed something up on the front of the motor during reassembly somehow.

[ct3155]

Ok so moving the car around today, I noticed that the check engine light would come on and stay on for awhile. While idling. Didn't die... But would the. Randomly turn back off... Related???

What all can cause the light to come on and stay on?

[bddog]

A few months back I was having similar problems. Got around to replacing the CPS. I went to zip tie the wires back while it was running and it stalled.
The harness just past where the CPS plugged in was shorted.
I spliced in new wire.
It has been fine ever since.

[SpecM]

Ok so moving the car around today, I noticed that the check engine light would come on and stay on for awhile. While idling. Didn't die... But would the. Randomly turn back off... Related???

What all can cause the light to come on and stay on?

stomp test for code?

[ct3155]

Stomp test spits out code 1262. "Engine has stalled while below 600 rpm"

lol thats not much help.....

[ct3155]

Who wants to teach me how to look at this CPS with a scope?? Where can I splice in to look at its signal?? Close to the computer somewhere?

[ct3155]

I've been talking to Brody over at Miller to see if he has any ideas. Here is my latest email to him. It outlines what i've found after further playing around

Hi Brody,

Problem showed up maybe a couple weeks after completing the car. However that was last summer as it's a track toy. I can confirm DME is not dropping power as we have back probed all of its 12v ins during the issue. No sign of power loss.

I can explain the problem a little more... It seem to experience the issue in two situations.

The first is start up. You turn the key and it fires briefly before the check engine light comes on and it promptly stalls. In order to start it, you must press the gas a little to get the rpms high enough to give it time to settle before the check engine light goes off. Once off, it's happy and idles away perfectly.

Second situation to make the problem show up. Is the act of FULLY depressing the gas under full acceleration and then letting off. As soon as you let off, check light flashes and ignition is cut. Give it two seconds and it's back to life.

Driving the car around town like a grandma, it shows no signs of problem. Revving under no load while in neutral, shows no signs of problem.

Only seems to show up on start up or flooring and releasing throttle under load.

Now here is what maybe is interesting..... You can put it in first hammer down all the way to the red line, let up to shift it will stall, run second up to redline, let off, stall... And so on.

Or you can put in fifth at 55mph so not yet in power band. Floor it, makes for a gentle acceleration, let off, and it will stall.

So it would seem the act of full throttle input and release is what does it... Doesn't matter what kind of acceleration.

Now as a trail and error sort of thing I ran it up to the red line in first and didn't release from full throttle as I quickly put in clutch to shift into second and released clutch. Did the same into third and fourth. No stall through any gear while "power shifting". Just when you release from full throttle.

Definitely load related as I cannot replicate in neutral.

Parts that are new this summer with next to no drive time:

-Crank position sensor, as the thought was loss of timing data
-throttle position sensor.
-idle control motor
-miller PSIK
-173 ECU
-oem BMW engine wire harness
-bavauto plug wires
-cap and rotor
-plugs
-Mystery E performance head
-ALL relays
-all gaskets and seals
-coolant temp sensors
-oem o2 sensor
-19lb fuel injectors

I think that's about it... I literally replaced EVERYTHING under the hood... I may be forgetting odds and ends.

How come it won't play nice?!

Any more ideas?

Thanks again, Chris

[SpecM]

I replaced the crank damper / harmonic balancer last week

still acts up, almost exactly like you describe

[FLG]

Whats your reisitance reading across pins 47 and 48 on off the dme connector?

[ct3155]

You guys won't believe this. But I fixed it!!!

So looking at my last post about my email to miller, I relized it's idle related. Not abruptness of throttle change.

Stomp test was giving code 1262. One of causes of this code is short circuit in idle system.

I replaced the throttle position switch.... So that leaves the idle speed control motor itself. Its test per the Bentley came out fine.... But I figured why not try it... The problem seems like it's 100% unrelated to this...

But guess what folks?! I just replaced it, NO MORE PROBLEM WHATSOEVER!!!!!

Fixed. With replacement of iac motor.

Fucking nuts right?!

[SpecM]

do what?

[ct3155]

do what?

Maybe I don't understand your post???

But what I'm saying is that I reaplce the idle speed control motor and the problem is 100% gone.

You know what I'm talking about..

The L shaped valve that let's a metered amount of air bypass the throttle plate. At least its L shaped on the late models.

I believe it's T shaped on early models.

Somehow it was short circuiting and messing with whole computer timing data...

So weird.

[SpecM]

my comment was out if surprise.
oh yes I know what you mean, I just find it strange.
I'm not doubting what you found, its just not what I was expecting.
im going to disconnect mine for a few days and see if it fixes mine too!

[ct3155]

my comment was out if surprise.
oh yes I know what you mean, I just find it strange.
I'm not doubting what you found, its just not what I was expecting.
im going to disconnect mine for a few days and see if it fixes mine too!

I still find it crazy amounts of strange.

What do you get when you do the stomp test? What code?? That really will tell you a lot.

It's so crazy to me that an internal fault in that motor could cause this problem. I have really no Idea how it was related.

How i tested my theory was take it out and open it all the way so the car just had a high idle, but drove around unplugged. NO PROBLEMS!!!

After replacement of new motor, perfect idle and no faults.

[SpecM]

I haven't been driving the e30 much in the last two weeks, but I have gone 5 drive cycles since unplugging my ICV and I have had no issues either!

besides the high idle and rather rich mixture (must be stuck in open loop with ICV disconnected)