code 42????

[loadedi812]

Hi everyone, I'm very new at this so it's probably the wrong forum for this question. When I check the codes with blinking engine light I keep getting code 42. I replaced the ignition module in the distributor and no change. I'm looking for different possible solutions. Any help would be greatly appreciated.

[damanx]

copied from elsewhere:

CODE 42
Trouble Code 42 indicates that there may be a malfunction in the Electronic Spark Timing (EST) system. During cranking, the timing is controlled by the ignition module and the ECM grounds the EST line. It expects to see no activity on this line at this time. When the ECM enters EST mode, it applies +5 volts to the BYPASS line and expects to see voltage variations on the EST line.
Reasons for the ECM to set Code 42:
? System in BYPASS mode (i.e. EST line supposedly grounded) but activity sensed on EST line
? System in EST mode (i.e. BYPASS line driven with +5 volts) but no activity seen on the EST line

Possible causes include:
1. BYPASS line is open or grounded
2. EST line is open or grounded
3. Poor connections between ignition module and ECM
4. Poor routing of EST harness and/or poor quality ignition wires (EMI induced electrical noise
5. Faulty or incorrect ignition module
6. Faulty ECM

[EagleMark]

Error Code 42 is also set if you dis-connect bypass and set timing. Stays set until batt is disconnected to clear codes.

So clear codes and then run engine, check codes to see if it comes back.

[loadedi812]

I have recently adjusted timing, but have reset computer multiple times. Without all the diagnostic tools, or better yet how much am I going to have to spend to get them, will I be able to fix this problem. Thanks for the replys.

[damanx]

What did you set the timing to?

Mark, is this code possible if the timing doesn't match the scalar?

He stated that he recently adjusted the timing, but we don't know if he disconnected the bypass when he did it.

[loadedi812]

zero with the brown black wire under glove box disconnected. That's what the sticker on the fan shroud said to set bt at.

[damanx]

Well that eliminates incorrect timing!

Maybe the EST is bad?

[billygraves]

...............

[loadedi812]

What I have seen is a loose ground on a cyl head cause this. Another is the By-Pass female terminal (under the glove box with the small connector) is enlarged (Loose fit). Oversized ECM terminals for the EST/By-Pass. I have seen a highly corroded distributor base set this and run very poor. Another is internally corroded dist cap, module connectors and green corroded pick-up coil terminals with early distributors.

Thanks Billy... was bad female terminal. was pullin my hair out.