I have 1984 Vette and after sitting at home not running for about 4 weeks it did not want to run. Had to crank it many times to get it going and the next time it decided to be nice and break down at home. (to me if you take care of your cars they will break down in front of your house and not 300 miles away)

symptoms- the car starts, runs for 5 seconds and then dies.

Checked the following:

-codes- no codes dispalyed
-fuel pump relay- Ok
-fuel injectors -ok (they function with the connection and when you take out the connectors they do not squirt fuel)
-fuel pump pressure- ok 15 lbs (measured before the fuel filter)
-fuel filter checked and changed it while at it (still same symptoms after the change of filter)
-fuel pump runs ok (2 sec w/ignition On and also providing constant 12v via terminal still OK)

I have used the diagnostic manual charts for the 84 vette and its good but it ledme once down a wrong path (relay) so I am asking for some help. Now it tells me its the ECM but I dont want to spend $90 and find out that it not it .
I hate to take it to the shop and have them charge me $300 to tell me its somethingthat I have overlooked.
It would eat me alive as I would rather fix it myself and learn the lessons for next time.

thanks \

I'm not familiar with the cross-fire, but 15 lbs of pressure seems low to me.

the fuel spec is 9-13 lbs

Ahh. I stand corrected. Sorry

I have a friend who had what sounds like the exact same problem in his RS Camaro. He changed out the ECM with one he had gotten from Ebay and it did the same thing still. He ended up changing and replacing a gazillion different items trying to track the problem down. Make a long story short he had a mechanis tell him to put the old ECM back in and then it worked fine.

I will get a hold of him to see if ever found out what the actual problem was.

To me it sounds like one of three things, Clogged fuel injectors, ECM, or the pump is not pumping even though it's getting juice. I know you don't want to spend unessesary money so check very carefully. GOOD LUCK

Intermittant ignition signal to the computer can cause this or I have seen the low oil press switch wired incorrectly (the wires get bleached out from oil/heat) bad low oil press switch, low oil press., bad grounds can cause all kinds of strange problems (clean them ALL) and use aluminum oxide paste (not dielectric grease), the TCC could be stuck on, wet or overly dirty air filter, injector flooding, plugged cat, IAC fubar or MASSIVE air leak, water in the tank, Ignition module or coil crapping out (see #1), and last but not least I have seen bugs plug the tank vent tube (I hate mud wasps)(but not 5 secs) Later years bad crank sig sender, I'm out of ideas, please let the forum know when you find out what "it" was.
Aloha

Ha!, I just noticed the date of post. oh well, hope it helps someone in the future! Been up ALL night... going to bed now. Aloha

Lol, I guess with 2 posts he probably won't be back to read this.


But for the record, the low oil pressure switch is a secondary power source for the fuel pump. Removing it or busting it with a sledgehammer won't effect anything, assuming the fuel pump relay is working, which is the fuel pump's primary power source.

There's a myth that this low oil pressure switch is used to cut off the fuel supply. Sounds nifty, but it simply isn't true.