kierantjones

hey guys i have recently completed a engine swap and we are at the final stages but we have a problem. when the car is cold and starts it starts up fine, the service engine light is on and fans are on. when the engine heats to temperature SES light goes out and fans dont turn back on until engine is cold and started again not even if the car sits and temp goes up. now when the engine is hot and you turn off the engine to goto the store or something, when you start it back up it runs fine for about 5 seconds then stalls out and Disels. if you rev the engine up and take off right away then you dont have any problems. and over some time it's doing it less and less. the engine now doesnt even idle. you have to keep it reved to about 1500 - 2000 rpm or it dies. i have replaced the ICM and that didnt change anything. and the PCM has a code 42 EST Ground and 51 PROM error. this PCM and engine had a 4L60E transmission but we converted it to T56 and havent flashed the PCM yet to the T56. but i think that has nothing to do with the engine doing that. any ideas? i heard it could be a vacuum leak. but WHERE to look? does it have to do with the little vacuum switch connected to the EGR pump? any help would be GREATLY appreciated! Thanks!

moehorsepower

iTrader: (3)

First off check your plugs, sounds like the engine was loading up at idle and the plugs are probably black with soot, second can you scan to see what it is doing in CL, are the O2's working? To check for vacum leaks, just get some carb cleaner / throttle body cleaner and with the engine at idle, spray around the intake where it meets the heads, if the idle goes up, there's your leak.

FAD2BLK93

I would definatley scan for codes and maybe look at the datastream when running. I had some idle issue about every 2 years i have to clean out the idle air control (IAC). The vacuum leak will usually be felt when u rev the motor up does the idle stay up for a few seconds and then come down? Thats one of the signs.

kierantjones

we have scanned the computer and the codes that came up were 42 EST Ground, 44 Left O2 Sensor Too Lean, 51 ECM Prom Error. we cleared the codes and the first one that re-appeared was the 42 EST Ground. there is this little vacuum switch that connected to the EGR pump. and it has frayed wires a little bit. no copper exposed. but what is that for? and im not sure but i think there is a shut off valve missing for EGR pump. where would that be located? pictures if possible. thanks for the help

noice

When you swapped the ICM did it run right for any amount of time? I had a GM ICM die on me and I replaced it with something off the internet that lasted only 15 minutes before throwing code 41 which is the oposite of your 42 code. I replaced it with a new ICM and everything works fine now.

Is is it a stock engine? Do you hear it knock at all when being revved or during hard acceleration? Does it backfire? Does the idle hunt?

Also where are you located?

96SilverZ

iTrader: (2)

Same thing happened to me. Factory Delco unit fixed it.