Early 2004, I fought with my 1994 Bonneville 3.8L SE stalling at high and low speed after one hour or so driving. The car did start each time after 5-10 minutes. After several hundreds of dollor and visits to mechanics, and dealer shops, I changed the crank shaft sensor and the problem immediately went away. Now a new problem has show up.

1. Service Engine Lights comes and stays
2. Pick-up speed is very poor
3. Trans shifting is poor
4. Stalls while coasting or constant low speed
5. Starts right back up

Remember, my last problem forced me to change fuel pump, fuel filter, ECM ( floor at passenger side) and few others. I am being told to consider three things: Fuel system, Emission, and Ignition system which is like going to NY looking for Auntie Sue on your father side.

Any help on how to check the code? Is there a website I can find these codes?

Help Please.

TO retreive the codes, jump connector A to B in the diagnostic plug. Then turn the key on.
THe check engine light will flash code 12...that is 1 flash then 2 flashes - 3 times I think.
Then the codes come, like 54 is 5 flashes then 4flashes...and so on.
Once finished all codes, it flashes 12 again and repeats.

www.avigex.ca/xport/plug.jpg
www.avigex.ca/xport/3800codes.jpg

I have had a problem with similar symptoms...was the MAF - mass air flow sensor...was dirty, cleaned it with alcohol..this one gives no code.
TPS - throttle position sensor - also a remote possibility - code 21 or 22.

BYE

LMP, Thank you for your help. I will try it this weekend. I appreciate the great info. :iceslolan

I cleaned the MAF but still have stalling problems.
Could it be anything else? Thanks

I cleaned the MAF but still have stalling problems.
Could it be anything else? Thanks


LMP, I had the car check to day and found the following codes:

P0131 - Oxygen sensor signal too low

P0134 - Oxygen Sensor circuit problem

P0171 - Fuel Trim Semsor lean

Could you point me what to attackle first?

Thank you

These codes point to the heated O2 sensor on the exhaust system...it would indicate either a faulty O2 sensor but it can be damaged wiring /corroded connectors too. Obviously these components need be checked.
Faulty exhaust oxygen contents measurements will force the computer to adjust mixture - that is fuel injection - in some extreme fashion - seems here that it went to extreme lean, which is totally relevant with coughing and stalling.
The codes you gave me make me think your car is OBD2...the codes list I gave you before were OBD1..sorry ...I'm a little surprised, I thought OBD2 did not appear before 1995...

LMP,

Thanks a lot. I have changed the O2 sensor today. I will drive and see what comes up.

Thanks again.




LMP, I had the car check to day and found the following codes:

P0131 - Oxygen sensor signal too low

P0134 - Oxygen Sensor circuit problem

P0171 - Fuel Trim Semsor lean

Could you point me what to attackle first?

Thank you

Hey I have a 94 Bonneville SE V6 and I experience the same problems you have listed:

I get a ding ding ding from the car and then this sequence starts.

1. Service Engine Lights comes and stays
2. Pick-up speed is very poor
3. Trans shifting is poor
4. Stalls while coasting or constant low speed
5. Starts right back up

Any help on this issue would be appreciated.

I hope this will help. I have cleaned the MAF and had it check with OBD2. The codes displayed is posted above. Two days ago, I have the Oxygen Sensor changed. I assumed the car has only one O2 sensor located behind the engine on the exhust.

The performace had improved but the service engine lights comes on. The worst of all is that the stalling has not stopped yet! Since Monday I have experienced four episodes. Let us hope some else could come with another lead.

eappiah: Well once you are back to normal, keep us posted....

IN the mean time, I would do a 0$ thing:THis is a no risk operation...
the "long time numbers" stored in the computer to make up for variations in the vehicle behaviour are kept and they would taper off to final new values in a matter of about a week of normal use when conditions change. However, you can return the data to "normal" values in 2 ways:
- either the technician with the SCANTECH can return them to default values (did he?) or
- you disconnect the battery, then turn the headlights on - they do not light up, of course, but this makes sure any residual charge in the system is dissipated. THe complete loss of voltage will normally return the computer data to default values....and all your programmed radio stations will have to be reprogrammed...sorry
This might force the system to adapt more rapidly to the new sensor...or it will change nothing and you tell us what happens next.

Just to mention that quite similar behaviour in other makes of car (Kia Sportage, namely) was very often traced to clogged catalytic ....did not hear of that with 3.8, but may be just check if the exhaust seems to flow effortlessly....

Thanks LMP,
I will look into the catalytic converter this weekend. I love my old ramshakle Bonne. It performed exeptionally well today in Detroit's 10+ inches of snow. I just want the stalling to stop.

Thank you.

aBOUT THIS:
"you disconnect the battery, then turn the headlights on - they do not light up, of course, but this makes sure any residual charge in the system is dissipated. "

you leave it like that for several minutes, say 15.

Any suggestion about the stalling? I drove it last Thursday without a problem but I am still afraid the stalling may come up again. I hope get the stored code erase will do the trick.

Thanks

My '99 would stall at low rpms and it turned out to be the fuel pressure regulator. I had it replaced and the problem went away.

Still stalling after cleaning the throttle body and MAF. Could the fuel pressure regulator be the problem or the fuel injectors?

Still stalling after cleaning the throttle body and MAF. Could the fuel pressure regulator be the problem or the fuel injectors?

First of all to clear up the OBD 1 and 2 issues

This car is HYBRID ODB1 with an OBD2 connector meaning you CANNOT JUMPER IT and CANNOT use *most* obd2 scanners to read it

with that out of the way I would be looking into:


FPR
TPS
MAF

Still stalling after cleaning the throttle body and MAF. Could the fuel pressure regulator be the problem or the fuel injectors?

The simple answer is YES, it could be those things. In my opinion though, I have my doubts. My first thought would be your crankshaft position sensor. Among other things, the pulses from the CPS trigger the fuel pump to continue pumping to maintain the fuel pressure.

There is a backup system, in case of CPS failure: If the oil pressure is up, the pump will continue pumping.

When you return to idle from speed, the oil pressure drops (this is normal). If oil pressure drops, and there are no CPS pulses, you've tricked your computer into thinking the engine is not running, so it shuts off the fuel pump!

Therefore, my theory is that you have an *intermittent* CPS problem. If it were constant, I'd think you would have starting problems.

Of course, this from the guy who can't figure out why his '91 won't start in the cold :( see my post in that (cold-start problem) thread... it might give you some more ideas.

The CPS was changed last spring. This solved the stalling problem and the delay to start back up problem. THe car ran fine untill Dec when the staling when de-aceleration to stop or at the stop position started. Not the car runs fine at high speed even at 25MPH.

Could EGR vale be the problem?

Hey I have a 94 Bonneville SE V6 and I experience the same problems you have listed:

I get a ding ding ding from the car and then this sequence starts.

1. Service Engine Lights comes and stays
2. Pick-up speed is very poor
3. Trans shifting is poor
4. Stalls while coasting or constant low speed
5. Starts right back up

Any help on this issue would be appreciated.

We have a 92 bonneville with the exact same problem. I replaced a corroded pigtail on the ignition module, replaced a faulty TPS, and checked all the grounds under the carpeting. The fuel pressure is over 40psi during KOEO, and 35 during KOER. The check engine light comes and goes, and usually when it comes on is when the car is about to cut off. I do not have an ozzie to check the square waves coming from the CPS either.

Anybody have any new ideas?

thanks in advance

Check your harmonic balancer to see if the rubber connecting the center section to the outer ring has cracked and separated. If so, the reluctor that passes through the Crank sensor is out of phase with the cam sensor, and the computer can't determine where the engine is in it's firing order.

I didn't notice any separation between the outer/inner rings...

I did change the TPS, but it still shows a 22 code for it. The voltage on the center wire reads .5v @ rest and 4.6v @ WOT.

Check out this thread about stalling bonneville...
http://www.automotiveforums.com/vbulletin/showthread.php?t=250962

I fixed the stalling issues a while back... basically, what was going on was a bad connection between the PROM and the ECU. If you wiggled the PROM while the car was running, it would ding, ding, ding, ding and ding some more and die. I put in an ECU from a buick and the car runs perfect now. Only thing that sucks is that I replaced the TPS, CKP, a pigtail on the ignition module and cleaned all the grounds before accidentally stumbling upon the ECU having an issue inside.

In other words, if your car starts that ding, ding, ding and stalling crap it's probably a defective PROM socket in the ECU.