Start Then Dies After 5 Seconds

[snowmoman]

I'm at a loss and need an opinion. I replaced the fuel pump module because it was not holding pressure. Also replaced fuel pressure regulator. Now it is holding pressure of about 48 pounds. Problem is the car starts and runs about 5 seconds or so and then shuts off. It will always start and do this. It sometimes shows a P0102 MAF code. One time it had this code when it was running OK and when I reset the code it started doing this. After a few attempts it started to run but now is doing this again. That's why I changed the pump. I'm thinking there might be a problem with the PCM. Seems like something is sending a signal to shut off the injectors. I have a new oil pressure switch and it registers pressure so it's not that shutting the car down.

THANK YOU

1996 Camaro RS 3.8

[snowmoman]

Re: Start Then Dies After 5 Seconds

I forgot to say I replaced tje MAF sensor a couple of months ago.

[techsan23]

Re: Start Then Dies After 5 Seconds

I'm assuming the security light is not on.

Since you have had the P0102 recently, I would probably start by testing the harness connection that plugs into the MAF sensor. Im not looking at a schematic, but when you unplug the connector you should be looking at 3 terminals. With a voltmeter set to DC volts you should be getting around 12 volts from one of the terminals (probably red or pink wire) with the key turned to the on position. Turn the key off, and set the voltmeter to ohms. Ground the black probe on the voltmeter again and bump the terminal (probably black or grey wire) with the other probe. If it has a good ground your reading will go to 0 or really close to it.

If you have a scanner you can simply check your sensor by looking at your MAF value with key on, then start it for the 5 seconds and see what value you are getting.

Having said all that, even with a bad reading from the MAF sensor generally the car will start and run, but its a starting point.

[snowmoman]

Re: Start Then Dies After 5 Seconds

Car won't run even if MAF is disconnected. Here is what else I found:

The VATS has not been disabled. The solid security light is on but not flashing. It was that way when I bought the car and was never a problem. The MAF I installed was rebuilt. The start issue began when I reset the P0102 code with my scanner. I wonder if I damaged the PCM?

One more thing. I measured the continuity between the MAF connector ground terminal and the engine. It had continuity so is good I guess.

However, I did the same with the positive terminal of the MAF connector and also got continuity to ground. This doesn't seem right to me. Doesn't this sound like a short? I'm only getting about 8.7 volts to the connector. I wouldn't expect continuity from positive to ground. I think this would play hell with how the PCM would read and control the injectors. These continuity tests were done with the PCM out of the car and the neg. terminal on battery disconnected.

Thanks for your help.

[nascar24jd]

Sounds like a VATS issue.

[techsan23]

Re: Start Then Dies After 5 Seconds

8.7 volts sounds a little low, but may just be from trying to start the car. A normal scanner reading should be around 4-7 grams per second at idle.

As others have posted, you need to address the VATS issue.

[snowmoman]

Re: Start Then Dies After 5 Seconds

Thanks everybody. I appreciate it. It may be VATS but I have driven it that way for two years with zero problems. But I will check it out.

[snowmoman]

Re: Start Then Dies After 5 Seconds

Just one more thing. Should I be showing continuity from positive lead
to ground on the MAF harness? Doesn't seem right to me.

[techsan23]

Re: Start Then Dies After 5 Seconds

If the + terminal is grounding then it sounds like a short to me.

The power for the MAF comes from the underhood electrical center, 20A fuse position 10 next to the fuse for the injectors. I'd still get rid of the VATS first though.