I have a 95 LT1 all stock. The car was running fine. Now when starting the car. The fans come on with the switch in the ON position. The fuel pump will only prime for about 2 seconds, and does not come back on once the cars starts. So it dies after about 3 secs of running.

Thanks for any help

 

the fans are comming on because the car is running in limp home mode, thats something that the computer does when theres some serious sensor problems.

check the m.a.f. sensor, make sure that the hose isn`t cracked or fallen off the throttlebody. also check to make sure that the maf is clean and dirt free.

the coolant temp sensor will also cause it to run in limp mode, its in the waterpump check to make sure that it`s plugged in.

also at this point you should be able to scan it and get the code to find out whats wrong with it.

 

I think it may be more serious than limp home. The fuel pump will only prime, and will not come on when the car is running, so it dies instantly.

Thanks

 

How do you know the pump shuts off? Have you scanned it? Do you still use OBDII?

 

I don't have a scanner. You can here the pump stop short on priming.

 

The pump is only supposed to prime for 2 seconds. You have to shut the car off for approximately 10 seconds before it will prime again.

 

I tried another pcm, and it still does the same thing. Your right on the priming. It does what it is suppose to do, but once the car starts the fuel pump will not come back on. Is there a way to get the car to flash trouble codes on the 94-95 cars? Yes it also has a OBDI 8051 pcm.

Thanks Again

 

You must use a scanner to get trouble codes.

How are you verifying that the pump is not running? The PCM will not allow the pump to run if it does not see any activity from the opti. You need to retrieve the trouble code(s) and see what is going on.

 

Shoebox, I went and got my laptop and cable. I tried to use freescan to read any trouble codes. The freescan software will force data between it and the pcm, but does not return any engine data or trouble codes. It shows bytes recv and send to be equal, the pcm is not volunteering any info back to freescan. Any ideas.

Thanks

 

If you have no SES (or did not have before), there may be no codes to retreive. You asked about scanning, but really didn't indicate that there was ever a SES.

 

Its weird that the freescan can not comm. with the pcm. I just tried it again and the car will start for about 2 sec. then dies. I'm 100% sure the fuel pump is not coming back on. I get no SES codes or Security Light flashing.

 

See if the cigar/accy fuse #11 in the I/P fuse box is good.

 

I checked all the fuses before, but I just went back through them and all were good. This thing is driving me nuts. Thanks guys for your help.

 

Same exact thing happens when you fry a PCM.

 

The car must be frying them somehow. The pcm on the car came from a running car. The only other pcm I have to try is a 96 OBDII will it fire the car? I never have tried swapping to a 96-97 pcm on a 94-95 car.

Thanks