ok i have a 84 corvett with crossfire inj , i was having a problem reading the codes just getting error communicating when trying to test as well as the ses light on all the time and would not reset after disonecting battery.

the engine has no ***** and is way rich and backfires on hard ecceleration...but is quite better with map sensor unplugged but then the engine smokes some.

i removed the prom and woohoo i can now read ecu error codes, but then the engine purrs along ....with a pop pop every 5 seconds. so i assume the prom is what is causing all the problems. so i am looking for someone to clarify if the prom being bad can cause the power problem, flooding ect.

I also wanted to know i have a 83 firebird for parts with the same crossfire injection system.. however the firebird is a 305ci and the vette is a 350ci. can i use the prom from the firebird without any major problems or damaging anything...they have the same ecu number but i cant read the prom numbers anymore to know if they are the same numbers.

if not interchangeable is my prom defective or just loss programming, the car sat for 5 years can that cause the prom to go bad.

any input would be greatly appreceated.

 

Hard to say what the actual cause is. It could also be that the ECM is on the way out. You can try the '83 Firebird PROM. However, one area that can cause problems is the differences in the transmissions. If the 84 has an auto with a TCC, can then only use the '83 PROM if it too is from an auto car.

If there is a 4+3 in the '83, the Firebird PROM won't control it. Not sure what would happen.

If may be from sitting that some of the connections are intermittent. As you R&R'd the PROM and that helped, do the same for the ECM edge card harness connectors. R&R them several times to get a better contact.

When you pulled the codes what came up?

RBob.

 

the 83 firebird is a automatic as well also with crossfire injection.

i could not read any codes with the prom in the ecm.....as soon as i remove the prom i can then read codes....i get the handshake code 12 wich is normal....but then i get the eprom error code 51 i think it was.

the ecm itself.. i tried for another one that i know was good (used my eprom) and same problem wont read codes and ses light on all time.

the 83 bird has auto transmission and crossfire but i diddnt want to blow anything up by using wron eprom