Help me figure out what's wrong in this CSV engine log...

[ryan.hess]

PHANTOM STALLS AT CLOSED THROTTLE & HIGH ENGINE LOADS #67-63-03 - (06/05/1996)
SUBJECT: PHANTOM STALLS AT CLOSED THROTTLE AND HIGH ENGINE LOADS (REPLACE FUEL INJECTORS)

MODELS: 1991-93 CHEVROLET LUMINA 1991-93 OLDSMOBILE CUTLASS SUPREME 1991-93 PONTIAC GRAND PRIX WITH 3.4L TWIN DOHC V6 ENGINE (VIN X - RPO LQ1)

CONDITION:

SOME OWNERS MAY EXPERIENCE A PHANTOM STALL WHEN THE ENGINE THROTTLE IS CLOSED AND HIGH LOAD DEMANDS ARE PLACED ON THE ENGINE. TYPICALLY THIS IS ENCOUNTERED WHEN THE OWNER IS MANEUVERING IN A PARKING LOT AT AN IDLE SPEED WITH A CLOSED THROTTLE AND PLACING A HIGH LOAD DEMAND ON THE ENGINE SUCH AS POWER STEERING. THE ENGINE COULD STALL BUT WOULD RESTART IMMEDIATELY. THIS TYPE OF STALL IS VERY DIFFICULT TO DUPLICATE.

CORRECTION:

A NEW FUEL INJECTOR, PART NUMBER 25170699, HAS BEEN RELEASED FOR SERVICE TO CORRECT THIS CONDITION. THE NEW FUEL INJECTOR IS DESIGNED TO FLOW RICHER AT A LOW PULSE WIDTH.

[SappySE107]

That wouldnt be stalling at idle, only idle at high low. It sounds to me like they came up with a way to rip people off by fixing an O2 sensor problem with expensive injectors. Parking lot maneuvering while at idle would likely be a cold engine and the O2 wont warm up if it does hit closed loop. Heated O2 would have been a better solution but it wasn't something GM wanted to setup I guess in 91-93.

I wouldnt run a larger injector, it will cause more problems than you are trying to solve.

[ryan.hess]

That wouldnt be stalling at idle, only idle at high *load.

Yes, mine does that too. Hell, anytime it's warm, it'll stall... at idle, when pulling into a parking lot... when going from D to R... Turning too quickly in a lot...

[brian89gp]

Now that makes sense, the O2 sensor is killing itself basically. You might want to try a 4 wire heated o2 sensor, have to run an Ign + and a ground but it will hook up and work fine. It may prevent it from leaning itself out to the point of stalling at idle.

[Cliff8928]

I was thinking about that whole heated O2 thing, but what i didn't know was when the heater is supposed to be on? Is it supposed to have power ALL the time? or just for a little bit when you first start the car or are at idle?

Cliff Scott
89 BerettaGT
89 Volvo740

[ryan.hess]

I was thinking about that whole heated O2 thing, but what i didn't know was when the heater is supposed to be on? Is it supposed to have power ALL the time? or just for a little bit when you first start the car or are at idle?

Cliff Scott
89 BerettaGT
89 Volvo740

Anytime the engine is on. So everyone is in total "uninanonimity" () that it's the o2 sensor's fault? I'll give it a shot, if so. btw - do 94's have heated sensors that are swappable? I need a model/year to get one from the parts store........

[ryan.hess]

New question - couldn't I just unplug the O2 sensor and the FPR, such that at high vacuum, the pressure would be high... hence solving the problem of not enough fuel at idle? Or am I missing something really big?

[SappySE107]

you can't uplug the O2 sensor without messing up the computer. Pulling the vacuum to the FPR will raise pressure at idle and cruise, which will cause the computer to pull back more fuel. Then you wont have a pressure increase at WOT...I wouldn't do that either.

[ryan.hess]

If you look at the last 1/4 of my 2nd csv, the crosscounts are steadily increasing, and it had been sitting/idling for a couple minutes. According to your "dead at idle O2" theory, wouldn't it not do anything? (keep in mind the middle values in the table (around the rich/lean count of 100) are when the laptop started freaking out, and I had to click the "force data" several times to get communication started again)

[SappySE107]

The O2 already warmed up though before that point. I havent noticed the O2 cooling down in any amount of time that I have had the patience to watch it while tuning idle. The O2 in your file hasn't cooled off so idle wont be an issue there. Are you saying it stalls after you drive around for a while, and then go down to idle through a parking lot or whatever and not hit the throttle?

[ryan.hess]

Are you saying it stalls after you drive around for a while, and then go down to idle through a parking lot or whatever and not hit the throttle?

Exactly. It only stalls when it's nice and warmed up, in closed loop, and <1000rpm.

[SappySE107]

Ok, well if you have been driving around and it still does this, then your problem isn't the O2 (but your first log file wasn't under those conditions). I guess you can try those updated injectors, but it makes more sense to me that the stock injectors are not spraying very well or something along those lines.

[ryan.hess]

Well I'm gonna reprogram the computer to richen it up at idle this weekend... we'll see what happens from there