Possible fried prom
 

I have a problem where my engine will start but shut off within 2-3 seconds.

I have tried different ecm's and nothing

I tried different proms with my moates adapter and nothing

I tried the stock prom alone and nothing.

I tried a prom from a '92 cavalier and it started and ran for about 20 seconds.

Is my reasoning correct?

I tried buying a prom from GM, but they said it was discontinued.

I could get one from TPI parts, but I gotta deal with brokerage to cross the border.

Could I buy a hypertech chip and plug it in to my moates adapter?

BTW, I have the axxf prom.

Please help!

Re: Possible fried prom
 

I tried another memcal(aujp).

It didn't work!

But a buddy of mine said that the cavalier chip has no vats in it.

So I cut the wires going into the vats module, white with black trace and purple with white trace and put in the resistor.

The car would stay running for a bit. But my timing is so out of whack the engine wouldn't stay running.

So I think I got the problem!
BTW, I took the vats out with my burnt chip and it still wouldn't start.

Re: Possible fried prom
 

That AUJP Memcal SHOULD have worked - especially if you burned your regular 305 bin on it. But even if not, a bone stock AUJP Memcal on an SD 305 wtih a 5speed should start the car (just not run right).

If a V6 Memcal worked (briefly) then the AUJP (if it IS a known good AUJP) should have worked too.

I was going to suggest the VATS module, but your car wouldn't even start in that case. (the starter won't work if the VATS is not reading your key right).

Did you try using the AUJP on a different ECM?

BTW, you may want to also post this problem on DIY Prom. I think we have more "followers" there that may be able to help.

As a LAST GUESS, maybe your fuel pump has died. And the V6 Memcal was "the last dying gasps" from you fuel pump. It could either be the "switch" of the fuel pump itself. Sometimes, whacking the bottom of the fuel tank gets you "one or two" last starts from the fuel pump if the fuel pump is just dying.

When you turn on the key, do you hear the fuel pump turn on and do you get good fuel pressure in the rail? If you don't hear the fuel pump "energize" then I would definitely go with a bad fuel pump.

Feel free to post this on DIY Prom.

Re: Possible fried prom
 

PS: Hypertech memcals for SD cars will not work. They ONLY have the eprom - they do not have any "netres" circuitry (because of the miriad of different "netres" used on each SD car) ... so Hypertech uses a "piggy-back" system JUST LIKE MOATES. Where they ONLY have the eprom and you must plug in your SD memcal to supply the "netres". And it's generally the "netres" that's goes, when the Memcal dies. So if you buy a Hypertech, you'll be sadly disappointed.

The more I think of this, I think it's fuel pump that's gone. Especially if you put on an Adjustable Fuel Pressure regulator and cranked up the fuel pressure. The fuel pumps on these cars are not very good, and a combination of running your gas tank with fairly low fuel (due to the high price of gas) and/or cranking up fuel pressure, makes the fuel pump extra hot and tends to burn them out even quicker (than they already do).

And if this is your ORIGINAL fuel pump, you are long overdue for your fuel pump to die. Even the newest car is over 16 years old.

Re: Possible fried prom
 

Thanks for your reply Grim.
I can switch between the cavalier memcal and the aujp(it is brand new from the gm dealer) and the aujp won't start the engine and the cav one will start the engine. Wierd huh??

Now for more bad news.

I tried to go back and start the car after my post. Now it WONT start. It just starts for 2 seconds and then stuts off.

I read somewhere that it there is an interruption in the vats, it takes up to 4 minutes to reset.

But like Grim Reaper said, if it was the vats, wouldn't it take my fuel AND the ability to crank the engine over??

I am loading up my car on monday and taking it to my old mechanic. he installs immobilizers in car(he's a whiz), he'll find the problem.
I'll keep you posted.

BTW, it is not the fuel pump(I have lots of pressure at the rail and I can hear my pump prime at every start. I also put in a 255lph fuel pump a couple of years ago.

Re: Possible fried prom
 

I hope that you find the bug soon.....

I know how short our summers can be.... and I feel your pain

May the force be with you...... Good Luck!

Re: Possible fried prom
 

Sounds like you have some form of an electronic/mechanical issue somewhere.

Based on what you are saying, it just may be the VATS module. I've never suffered THAT problem (one of the few). When it was the "resistor pellet reader" in the key, there is NOTHING. The engine would not crank or anything. Power to everything else, but the engine would not crank.

But a "flaky" VATS module COULD cause that problem. The Cavalier does NOT have any VATS code BUT because it's not the right calibration, it won't fuel the injectors properly either. I know that when I had someone try to steal my car and triggered the VATS SHUTOFF, I could not start my own car EVER. I had to have it towed to a GM dealers and they did the reset. I wished I had asked how to do it.

Maybe you should make a post on the Tech/Board (on this issue) and ask how you "reset" the VATS so you could try your new AUJP memcal WHICH SHOULD work (though not well) until you re-program it with your proper bin.

Re: Possible fried prom
 

It wasnt a vats problem!

It was a grounded out throttle position sensor. My mechanic put in a relay from the tps to the zex dry nitrous box .
The day that my car calved, I washed it and some water must have dripped on the relay and shorted it out!!

UGGGHHHH, I have been down for a month and had numerous people come and try to look at it and he found the problem and fixed it in less than an hour!

I took the car out for a drive today and boy it feels good!!

Re: Possible fried prom
 

Congratulations!!!!!!! :driving: :goodjob:
Sometimes it just takes another set of eyes/hands

I hope to have mine out soon, we'll see what kinda bugs I have......

Enjoy the rest of summer....