AAAAAAAH! Phantom stalling again!

[Lyle's GTP]

Hmmmm, I don't blame you it's a expensive little POS isn't it? I'm sorry I don't know the norm. But this program you are using I interested where did you find it and was it expensive? Have you had your injectors checked/properly cleaned at all, maybe it's not enough fuel?

[ryan.hess]

Do a search on it, it's called freescan, and I'm using a homemade ALDL cable.

[Lyle's GTP]

Cool I'll check it out. What type of hardware do you need? I'll ask my auto. tech. brother in law about your stalling thing.

[ryan.hess]

http://www.andywhittaker.com/ecu/aldl_hardware_cont.htm you want the MAX232 circuit. the 2 transistor never worked for me. Back to the topic at hand - If I posted a pic of my oscilloscope connected to the O2 sensor, would anyone be able to tell if it's working or not? I'm getting wierd readings.....

[ryan.hess]

Well, I replaced the O2 sensor, because the old one was bad and not responding at all to lean/rich conditions. Now my line crosses 450mv every second or so (still seems a little slow, but a big improvement from before) Seems to be running better with less hesitation... we'll see if this corrects the stalling.

[Lyle's GTP]

Good luck man, I've replaced a ton of parts chasing my idle/power problems and still have them. I can't get any educated info up here, no body knows about these cars.

Lyle

[montessgtp]

My car use to stall like that when my IAC went bad..would do it from 0-20 mph car would never find a stable idle either.. car to use alway at 700 one day it start doin this bounce around deal...where it couldent find a normal idle n would stall when it did...seriously replace your iac or clean it.

[ryan.hess]

My car use to stall like that when my IAC went bad..would do it from 0-20 mph car would never find a stable idle either.. car to use alway at 700 one day it start doin this bounce around deal...where it couldent find a normal idle n would stall when it did...seriously replace your iac or clean it.

It has been cleaned, and it always finds a perfect idle, so I don't think that's it... I'm starting to suspect a vacuum leak, but won't be able to confirm until this weekend when I get some more time... But, since I replaced the O2, hasn't stalled yet. Of course, that means nothing to me.

[blk92z34getrag]

Check the intake gaskets... they're notorious for leaking. The plenum and lower intake gaskets are what I'm referring to.

Also... there's a service bulletin that was posted somewhere on here for phantom stalls at high load low speed conditions... I'll see if I can find it. It involves buying some HELLA expensive injectors from GM to correct.

Ah, here you go:

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. BEFORE REPLACING THE INJECTORS, REMEMBER TO CHECK THE FOLLOWING:

1) MINIMUM AIR RATE SETTING.

2) VEHICLES EQUIPPED WITH MANUAL TRANSMISSIONS: CHECK CRANKSHAFT END PLAY, REFER TO BULLETIN 236007.

3) POWER STEERING PRESSURE SWITCH.

4) MAKE SURE THE LATEST CALIBRATION IS INSTALLED IN THE VEHICLE, REFER TO BULLETIN 336506.

PARTS INFORMATION

PARTS ARE EXPECTED TO BE AVAILABLE FROM GMSPO ON JUNE 10, 1996.

QTY PART NUMBER NAME

6 25170699 INJECTOR ASM - M/PORT FUEL

WARRANTY INFORMATION

FOR VEHICLES REPAIRED UNDER WARRANTY, USE:

LABOR CODE: J5650 INJECTOR, FUEL - REPLACE LABOR TIME: USE PUBLISHED LABOR OPERATION TIME.

FIGURES: 0 ATTACHMENTS: 0

GENERAL MOTORS BULLETINS ARE INTENDED FOR USE BY PROFESSIONAL TECHNICIANS, NOT A "DO-IT-YOURSELFER". THEY ARE WRITTEN TO INFORM THOSE TECHNICIANS OF CONDITIONS THAT MAY OCCUR ON SOME VEHICLES, OR TO PROVIDE INFORMATION THAT COULD ASSIST IN THE PROPER SERVICE OF A VEHICLE. PROPERLY TRAINED TECHNICIANS HAVE THE EQUIPMENT, TOOLS, SAFETY INSTRUCTIONS AND KNOW-HOW TO DO A JOB PROPERLY AND SAFELY. IF A CONDITION IS DESCRIBED, DO NOT ASSUME THAT THE BULLETIN APPLIES TO YOUR VEHICLE, OR THAT YOUR VEHICLE WILL HAVE THAT CONDITION. SEE A GENERAL MOTORS DEALER SERVICING YOUR BRAND OF GENERAL MOTORS VEHICLE FOR INFORMATION ON WHETHER YOUR VEHICLE MAY BENEFIT FROM THE INFORMATION.

COPYRIGHT 1996. GENERAL MOTORS CORPORATION. ALL RIGHTS RESERVED.

[Anonymous]

Injectors aint cheap, so I'm gonna wait until my current IAC starts acting up again.

[blk92z34getrag]

I've also heard that the Accel Stage 1 Injectors for our engines (yes they do make aftermarket injectors!) will cure the problem too, and I think they're like US$190 from Summit. Though I have no proof to back this up other than someone claiming they helped. Might be worth a shot.

[ryan.hess]

I'll be taking it to the dealer soon (maybe this week) to diagnose. It's stalling in the driveway all by it's idling self now. But curiously only when it's really warm (driven all day). Hopefully they'll be able to recreate a stall w/their scanner attached.

[Lyle's GTP]

Murphy's law states: "They will try for two days of considerable effort, and find nothing, but when you take it back home it will die in your driveway."

Lyle

[Anonymous]

I'll be taking it to the dealer soon (maybe this week) to diagnose. It's stalling in the driveway all by it's idling self now. But curiously only when it's really warm (driven all day). Hopefully they'll be able to recreate a stall w/their scanner attached.

Bad idea.

I took mnine to the dealer, 250$ later and it still stalls.

"We replaced your IAC and 3 vacuum lines and we couldn't get it to stall."

first stoplight while im driving, it stalls. Next light, the rpms drop to like 400.

I'm very unhappy. It rarely stalls anymore, but it is still rough. It dives way down at lgiths, but normally pickls back up.

[blk92z34getrag]

Yeah the whole stalling thing gets really old. My friends and I will be going somewhere, I stop at a light to make a turn, with my signal, and it died when I press the clutch. "Dude your car is f*cked up!" "No these engines are just made to go! Not stop, hence why I smoked your civic ass."