vetdrem

I have been having an intermittent starting issue. Some days it starts right up and some times it will not start. On the times it does not start, there is no sound at all. And the battery will still have 12 volts +. I can usually put a set of jumper cables on it and hook it up to someone else's car that is running and then it will start right up. The other day it would not start and I hooked up jumper cables to it, it started up but was idling at a very high rate. I could not get it to idle down so i smacked the ecm computer under the hood real hard which caused the car to die. Now it just turns over but will not start. I checked for trouble codes by jumping a to g like i have in the past but now only the sys flashes 3 times and no codes are given.

383vett

Just like a woman, probably didn't like the hard smack. Sounds like you need a new one. Good thing they don't put you in jail for ecm abuse.

vetdrem

You got that right! Lol Anyway, the fuel pump is not coming on when I turn the key to the on position now. Could me smacking the ecm cause this to happen because of not communicating?

N42375

What you had was most likely a component failing on the ECM pc board or a bad connection on the wire harness. The technical term for smacking the ecm was " doing a Fonzi" according to my mechanic. My 90 coupe had an intermittent issue this summer. It would run great for 4 days, then on day 5 it would stumble and quit after 4 blocks. My mechanic told me do a Fonzi on the ecm. One of two things will happen- it will get a lot worse or get a lot better. I got lucky, my ran perfect the next day so I could drive the 40 miles to get a new unit installed. For what's it worth, the first replacement unit was defective-the car wouldn't even fire. The good news is that the ecm only costs about $115 and is easy to install. with my new ecm, my car seems to have a little more zip and the gas mileage improved by about 1.5 MPG. Good luck.

1stVetteFinally

Where did you find a new ECM for a C4? They have been impossible for me to find?

aDigitalPhantom

From what I have seen only the 92-93 are hard to find.

1stVetteFinally

figures

N42375

The ecm for my 90 was obtained thru corvette sports. Contact them at 920-467-2833. Ask for Joel. They specialize in ALL year Corvette repair and restorations. Located in Sheboygan Falls, Wisconsin

aDigitalPhantom

The 92-93 has a different PCM then the 90-91. IIRC the 90-91 ECM was a 1227727. This ECM was also on tons of cars with the 3.1 V6. From my experiance the only thing you need to change on one from a V6 is the PROM to the Corvette PROM then it will work correctly.

jispr

Autozone $170.00 Cardon reman. your eprom

THE 383 admiral

Open the ECU re-seat the prom carrier.
then re-seat the harness connectors.

1stVetteFinally

Yes they are. Best I have found is shops that rebuild your ECM for you. Priced about the same as buying a new one (when they were available). With shipping costs, it'll cost me about $200 to get it done.

It's so much of an issue that I'm considering ripping out all three control modules and rewiring my car. Screw ASR, and I can do an aftermarket ABS. Biggest problem with that is how to get the dash instrument cluster to work.

aDigitalPhantom

The tachometer, speedometer, coolant temp, volt gauge, fuel level will all work with out the factory ECM. I think the Oil temp would work also. The fuel economy readings would not, but every else should as far as I know.

PS
The speedometer would still need something to connect it, but it does not need to be the factory PCM.

1stVetteFinally

Like what? I was sure the gauges would work, but I didn't think the speedometer would without the factory ecm