Hi guys, I am new to this forum but so far I love what I see!!! Anyway here is MY problem. I have a 94 ssei, first thing I noticed was my check engine light would come on after driving (usually highway) for 20 -30 minutes. Also noticed a lack of power. After analyizing it for awhile I noticed that when the light came on my boost would only go to 1 or 2, normally I could get 6 - 8 lbs. Car is completly stock except for a remote starter.

I did not have access to a scanner but finially found someone that had one and they pulled out a P1640 code. He cleared the code, I drove the car, the check engine light came back on and had the same code.

Now all of a sudden I am pulling out of my garage one morning and the car just kills, takes about 2 minutes of canking and it starts back up, on the way to work I am doing 65 - 70 and the car just kills. I put it into nuatral and it starts back up. this happens 2 or 3 times on the way to work and on the way home. Oh also when it kills and starts back up the Check enine and Traction control lights are on.

I am not sure what to do, I just replaced the fuel filter, spark plugs and spark plug wires.

Any help would be great

Thanks
Dave

The real question is what that P1640 code means....that and the gang will need what year/model your car is.

I dont have the code for P1640 but feel the problem is with your PCM. 1639 is low reference voltage (5 volts for pcm). Check your harness going to the computer and check the overall mounting and condition of the PCM case. There is a member here that took their pcm apart and found corrosion shorting out the pcm board?

Can't help, but wanted to say Hi to the newe MN guy!!

A bad engine ground would be the first place to look, then progressively check the PCM
connector and sensor connections.

yeah i would check for a bad ground first.

i think it the Torque converter lock-up switch

wow, thanks for the advice, and thank you for the nice welcome. Anyway my car is
a 1994 Bonneville ssei. I found some references to the P1640 on some threads on this formum, they talked about the TCC. Also I stopped at a Pontiac dealer and talked to a machanic, he didnt want to give out much information but he said it was a code telling the computer that there is some bad information coming from someplace. WOW thanks for the indept info, isnt that what every code is? He than asked me if I have had any shifting problem lately, that question leads me to believe the TCC or something like that.

I am not sure if I am now chasing two seperate problems or what. I was looking in my chiltons book and the also talked about the TCC however nothing mentioned anything about not starting and killing during driving. I started to think of the fuel pump, I thought I would do a pressure test of the fuel line. I went and bought a pressure gauge but of course when I got home I found I did not have the adapter to hook it up to my car. but what I did do is turn the key on, listened to the system pressurise, shut the key off and pushed the test valve in with my finger i kind of exspected to get a good squirt of gas out of it but it only went sput and a small spray shot out a couple of inches. That seems fishy to me, I am going to pick up what I need to test it with the gauge tonight. I will let you all know what I find. Oh by the way my chiltons book said the pressure should be 40- 45 psi. Does that seem high? my gauge only goes to 14 psi

Low boost and the QDM1 code may point to the BCS (Boost control solenoid). You may also have a vacuum leak. Check all the vacuum lines around the SC and make sure they didnt pop off. You can also get some carb cleaner and gently spray around the throttle body and vacuum lines and if the car revs higher then you have a vaccum leak.

The QDM primary function is to supply ground to the item being controlled, and it has a fault-detection circuit. It will set 1640 when:
The engine is running.
The PCM detects an improper voltage on a circuit connected to the QDM
The above conditions last for at least 5 seconds.

The solenoids under control are the Boost control, the Evap Purge, and the Traction-control-apply (inside transaxle)

Since your symptoms seem to apply to ALL solenoids, the problem is almost surely with the PCM or the connections to the PCM. Otherwise, you would only have the symptom associated with the affected solenoid, such as low boost if its the boost control, dies if its the evap purge, and no TCC if its the Traction control.

You may also want to check the cruise-control fuse, 15 amp, and the 10 amp cooling fan/TCC fuse, if you haven't already dones so. They appear to be part of the overall circuitry, supplying the "plus" power to these 3 solenoids.

(The cruise control fuse is said to be in the relay centre, and the 10 amp cooling fan/tcc fuse is in the fuse block.)