PL log captures stall problem WTF is causing this?

[TR Custom Parts]

Intermittent stall problem. Everyone once in a while my GN will just stall for no reason. No early warning, just shuts off usually at an idle. Starts right back up. Doesn't happen all the time, just out of the blue once in a while. No warning signs of impending trouble. Check out the PL log around frame #9248, this is where it stalled out. Car ran fine the rest of the night. Had the AC going when it happened but it will also do it with it off.

And I guess I am the proud owner of the fast mph TR ever. Look at the log at around frame #722 - 240mph! Where did that glitch come from?

 

[VIN7]

Mark,

I chased phantom cutoffs for a while, no codes, nothing out of the ordinary. Would start up immediately. Was the crank sensor, the original lasted 22 years.

 

[TR Custom Parts]

New GM sensor put in about 1 year ago. Clearances are correct, did this stalling before I replaced it.

 

[CGASTON]

Mark,

My car does that when it goes from open to closed loop. Try putting your car in open loop an start it. That fixes mine..

 

[RmvBfrFlght]

Intermittent stall problem. Everyone once in a while my GN will just stall for no reason. No early warning, just shuts off usually at an idle. Starts right back up. Doesn't happen all the time, just out of the blue once in a while. No warning signs of impending trouble. Check out the PL log around frame #9248, this is where it stalled out. Car ran fine the rest of the night. Had the AC going when it happened but it will also do it with it off.

And I guess I am the proud owner of the fast mph TR ever. Look at the log at around frame #722 - 240mph! Where did that glitch come from?

The 240 MPH glitch is easy to explain, on rare occasions the rotating bar in the speedometer sits right on the edge of the optical pickup beam. This causes the VSS input to the ECM to be oscillating at a faster rate then the 2K PPM it should be. I've seen the same from time to time.

As for the stalling, hard to say. The only anomaly I could see is that the NB O2 goes to 0 volts just as the engine RPM is sagging. The WB shows a normal 14.3:1 AFR during this time.

Check the battery ground cable and the grounds on the back of the cylinder head.

RemoveBeforeFlight

 

[dennisL]

I agree that you should check/clean the battery cables and grounds at the firewall. While you're under the hood, adjust the throttle stop to lower the IAC counts at hot idle as its high.

 

[TR Custom Parts]

Grounds - now that I think about it this seemed to start taking place not long after I did the Caspers ground relocation installation a while back. Used a good crimper and soldered everything and followed instructions for the where to attach everything. We have to revisit that.

Have another O2 sensor I can throw at it.

IAC, would it read higher with the AC on?

Today when I was getting ready to leave a show I started the car up to let it warm up a bit while waiting for some friends. Told one of them watch this it will stall in a couple of minutes and sure enough it just shut off while sitting there.

 

[TurboBob]

at frame 9240 or so:

injector pulsewidth is not dropping, so the chip is not shutting it off.

the O2 starts high, like a TT chip will idle. then starts to toggle, then falls to the floor, then the engine stalls. My vote is FUEL PUMP

Bob

 

[TurboBob]

i'm not sure why the wideband is not agreeing with the main o2

 

[RmvBfrFlght]

IAC, would it read higher with the AC on?

Yes, any additional load on the engine will cause the IAC to step out. A/C, fan(s), backlight heater, pressure on steering wheel, and so on.

RemoveBeforeFlight

 

[TR Custom Parts]

at frame 9240 or so:

injector pulsewidth is not dropping, so the chip is not shutting it off.

the O2 starts high, like a TT chip will idle. then starts to toggle, then falls to the floor, then the engine stalls. My vote is FUEL PUMP

Bob

New fuel pump from Racetronix, just replaced when chasing my other issue, no 1-1 fuel pressure increase. Fuel pump pressures were logged as well, don't really see any issues at idle, did this with the old pump as well.

 

[TR Custom Parts]

Yes, any additional load on the engine will cause the IAC to step out. A/C, fan(s), backlight heater, pressure on steering wheel, and so on.

RemoveBeforeFlight

IAC checked out fine after initial warmup, as you can see AC along with dual fans was on as well as fan for trans cooler, radio on etc when the higher readings for IAC appeared.

 

[TurboBob]

New fuel pump from Racetronix, just replaced when chasing my other issue, no 1-1 fuel pressure increase. Fuel pump pressures were logged as well, don't really see any issues at idle, did this with the old pump as well.

in looking at input 5, yeah, it seems your fuel pressure is behaving.

hmmm.

gonna have to ponder this one for a bit. What do you have your cam sensor set to? How old is the sensor?

This one looks like it happened when you were coasting to a stop, do you have a log of it stalling when just idling while stopped?

Bob

 

[TR Custom Parts]

Yeah Bob, this one was coasting to a stop, when I get some time I will let her idle in the driveway and try to record an idle stall.

I do have a BOV on the car vented to atmosphere. If I rev the car and let off it will instantly stall but know better to do that. Don't think the BOV is opening on it's own but was thinking it might have something to do with this.

 

[Pronto]

Can you disable the BOV? See what happens then...

 

[BEATAV8]

Mine died a few weeks ago running at WOT. No known reason. Hasn't done it since....

 

[TurboBob]

Yeah Bob, this one was coasting to a stop, when I get some time I will let her idle in the driveway and try to record an idle stall.

I do have a BOV on the car vented to atmosphere. If I rev the car and let off it will instantly stall but know better to do that. Don't think the BOV is opening on it's own but was thinking it might have something to do with this.

I would think you'd see the MAF and injector values fall if that were happening.

But worth experimenting with.

Bob

 

[juan89]

I had a similar problem with my GN . There was too much play on the cam sensor, it was like 1/4 inch. I took the cam sensor
cap off and pulled on the rotating part and saw the play.

Regards,
Juan