91 Park Avenue starts then shuts off...

[gregk24]

It only starts when you give it gas, but as soon as you let off it shuts off. Here are the stored codes:
- 38 - brake switch circuit
- 41 - cylinder select error- mem-cal or ecm problem
- cam sensor circut (3.8 models)
- 42 - bypass or electronic spark timing (est) circuit
- 66 - pressure sensor or circuit air conditioning
- 67 - nothing listed on gm trouble codes site, do you know what this is?
This is my brothers car, but he is very short on cash, any ideas what the issue is? What should we have fixed first?

 

[spasm3]

So many, I might clear them all out then restart the car and see what your get. Has this car been sitting a lot? My first thought is the IAC but i don't have a book on your model. You may need a hayes book or a trip to someone who can hook it up and see all the sensors.

 

[supton]

It's an old mans car. Probably needs a nap.

I too would think idle air control, or whatever adjusts idle. If you keep your foot in it, will it stay running? Can you "idle" at say 1,000rpm? Or does it run poorly above idle?

 

[eljefino]

The codes 41 and 42 worry me, I'd take the connections off the ignition module and check 'em out.

Do you hear the fuel pump when it dies? These cars use the oil pressure to keep the pump going but a relay to initially prime the system. If they stall and things are working right you hear the FP for a sec or two while the oil pressure dies back down.

 

[Bud_One]

Code 41 - Cam sensor magnet ?

http://forums.aaca.org/f116/1991-3800-buick-obd-1-code-255019.html

 

[gregk24]

Originally Posted By: supton
It's an old mans car. Probably needs a nap.

I too would think idle air control, or whatever adjusts idle. If you keep your foot in it, will it stay running? Can you "idle" at say 1,000rpm? Or does it run poorly above idle?


Yes, it stays running when you give it gas, and it runs fine.

 

[spasm3]

Did he by any chance, recently wash, or pressure wash the engine?

 

[TMoto]

My '01 Regal did this a few times at random and I suspect it's the IAC valve but haven't changed it out yet. I discovered that if I let it warm up with my foot on the gas idling, it will then run just fine after it warms up.

 

[3800Series]

I guess I'll going the wagon and simply state my regals IAC needs to be replaced also.

Might want to consider getting a bottle of MAF cleaner and clean the MAF, the idle air sensor, and the throttle body. I replaced my MAF a few days ago and my problems with starting went away.

Theses vehicles are solid and run forever however if you don't keep up on maintenance and you ignore it when stuff stacks up and you got a big problem its a lot harder to fix. So many people do this they will never repair anything and leave ijt how it is then one day the car doesn't start and they act like the cars junk. If you don't take pride in ownership and repair problems as they come up you will be left with a far larger repair down the road.

 

[gregk24]

Originally Posted By: spasm3
Did he by any chance, recently wash, or pressure wash the engine?


Yes, I did about a month ago. I covered up all the electronics though. I just used a garden hose and quickly rinse off what needs rinsing. I dont drench anything and use little pressure, but that was a month ago and its been fine until now. Why, what are your thoughts?

 

[Koz1]

Computer main connection de-oxidizer.
Who knows.
Take all the computers out and warm them up in the house clean them with electrical cleaner.
Grasping here.
Never pressure wash the engine.
A good mechanic told me that so I dont.

 

[gregk24]

Originally Posted By: 3800Series
I guess I'll going the wagon and simply state my regals IAC needs to be replaced also.

Might want to consider getting a bottle of MAF cleaner and clean the MAF, the idle air sensor, and the throttle body. I replaced my MAF a few days ago and my problems with starting went away.

Theses vehicles are solid and run forever however if you don't keep up on maintenance and you ignore it when stuff stacks up and you got a big problem its a lot harder to fix. So many people do this they will never repair anything and leave ijt how it is then one day the car doesn't start and they act like the cars junk. If you don't take pride in ownership and repair problems as they come up you will be left with a far larger repair down the road.


Thanks for the lecture, may I say that I am one of the biggest advocates of preventative maintenance and having problems fixed when they crop up. HOWEVER, this is not my car and I have already put a fair amount of my money into having the maintenance brought up to date on it. I know these are good cars, and I want it to last a long time for him. I am not familiar with these older GM's so I look to BITOG for help, thank you all for the replies but it doesn't seem like anyone knows for sure what it would be (thats ok as no one can diagnose anything over the internet). Hopefully he can have it looked at by one of our family friends and have the issue fixed the first time on the cheap.

 

[CurtisB]

Take the IAC valve off, than start the engine. If it stays running without extra throttle than you have a bad IAC. The idle will be really high without it on there too.

 

[spasm3]

Originally Posted By: gregk24
Originally Posted By: spasm3
Did he by any chance, recently wash, or pressure wash the engine?


Yes, I did about a month ago. I covered up all the electronics though. I just used a garden hose and quickly rinse off what needs rinsing. I dont drench anything and use little pressure, but that was a month ago and its been fine until now. Why, what are your thoughts?


Check and clean the connections at the Ignition module. Perhaps some water got in, mineral deposits or corrosion. look at the link below, its older and a fiero page but i think it still applies.

http://www.fieros.de/en/v6help/code42.html

You may have an ignition module going out.

 

[clinebarger]

Originally Posted By: gregk24
It only starts when you give it gas, but as soon as you let off it shuts off. Here are the stored codes:
- 38 - brake switch circuit
- 41 - cylinder select error- mem-cal or ecm problem
- cam sensor circut (3.8 models)
- 42 - bypass or electronic spark timing (est) circuit
- 66 - pressure sensor or circuit air conditioning
- 67 - nothing listed on gm trouble codes site, do you know what this is?
This is my brothers car, but he is very short on cash, any ideas what the issue is? What should we have fixed first?


41 & 42 first.

Code 41, Loss of cam signal.
The easiest test is to back-probe the Brown & Black wire at the ICM (Ignition Control Module) with the key-on while barring the engine SLOWLY.
Simple high to low signal from the Cam Sensor, The voltage will be high 'till the magnet on the cam gear passes the sensor.

1. First, OE ICM's produced 10 volts as a power supply to the Cam & Crank sensors it is not uncommon to see lower voltage on the signal wire. Flow charts say 10-11 volts, but most aftermarket Ignition (IGN) modules do not put out that much. Typical to see 5-7 volts in most cases.

2. Probe the Brown/White wire at the module. Roll the engine by hand and see if voltage toggles to 0 when the magnet passes the sensor.

3. If no change in voltage, then remove the sensor from the engine, and roll the engine around until the magnet is found on the cam gear. Check for it to be missing or damaged.

4. If OK with the sensor out and key on, run an alternate magnet past the sensor and see if the 6-7 volts is pulled to 0 volts. Sometimes the magnet is not damaged, but can be weak.

If no voltage is on the Brown/White wire, Check for voltage on the White/Black wire at the Cam Sensor connector, And ground at the Grey/Red wire at the Cam sensor.





Code 42, EST circuit.
1. Disconnect the Engine Control Module (ECM) and then turn the key back on.

2. Connect an ohmmeter to terminal G2, a White wire at the Grey ECM connector. The resistance to ground value should read less than 500 ohms.

3. With the ohmmeter still connected at terminal G2, connect a test light to Battery Positive (B+) and then probe terminal G7, a Tan/Black wire at the Grey connector. The ohmmeter value should have switched from under 500 to over 2000 ohms.

4. If this switching did not happen, check the White and Tan/Black wires for an open or short. If both wires are OK, the ignition module is faulty.

5. If it switches from under 500 to over 2000 ohms, the module and its wiring are OK, and the ECM is faulty.



Code 38, TCC brake switch error, Check for power on the Pink/Black at the brake switch, Check fuses if no power is found.


60's codes are HVAC, I'm guessing not relevant at this time.