Hi everybody,

Here's my setup:

350 vortec TPI, 7730 custom prom (still tuning it). ACCEL coil + module in distributor cap. the prom in the ECU is a stock 350 TPI auto from a 90 camaro mounted on a socket(from moates) to keep ESC working.

the previous engine was a 305 tpi.

Here's my problem:
Engine starts ok, runs ok, but the ECM rise code 42 about 10 seconds after start.

question: is it due to that coil+module system? I bought it a while ago and don't remember if it's specific to 305 or if it's standard.

Is it a common problem?

Thanks.

 

Code 42 is an ESC failure.
Essentially, it means the ECM has tried to create a "test" knock, to verify that the knock sensor is working, and was unable to detect a knock in response to advancing the timing.
Either timing advance doesn't work, or the knock sensor doesn't work, for whatever reason.
Which is it ?
Grab a friend. ( since you've only got a few seconds to do this )
Take a long socket extension. ( or any steel rod ) Put one end on a head bolt somewhere near the knock sensor.
Have a friend start the engine. As soon as the engine is running, start rapping on the extension with a 2 oz. tap hammer, to simulate ping, ping, ping......
( a ratchet handle will work. Point is to create the sound of a ping without doing any damage )
The ECM should detect this, retard the timing, and NOT set code 42.
If it doesn't set the code, the knock sensor works, look at the ESC. ( probably timing wasn't changed, even though the ECM tried )
If it does set the code, the sensor doesn't work, so start there.

 

Cflick, what you described is for a Code 43.

A code 42 is usually the timing is wrong. If you have the "set timing connector" disconnected, it will set a code 42. That's a tan/black wire on the passenger side by the shock tower. If you have the timing too far advanced or too far retarded, it will set the code, but its almost impossible for the distributor to move far enough physically. It could be the module as you suggested, either an open/shorted wire going to it, or something similar. If it was bad or wrong I would think the car wouldnt run at all.

 

Doh !!

Right you are !
( and I agree with the rest )