Ok, I keep getting the blinking code 42. I have swapped ECM's, new igintion module, whats left??

 

Code 42: Book1
Poor electrical connection, open or short in circuit, defective ignition module, defective ECM

Code 42: Book2
Electronic Spark timing bypass circuit or EST circuit is grounded or open. A malfunctioning HEI module can cause this code.


I'm about to call on this engine and slap a new one in it.

 

When you say blinking is that just when the codes are blinked out? Or is the SES light always on? This code will be set whenever the EST line is opened to set the timing. If blinked out ignore it.

Takes 50 no malfunction engine starts to clear any codes. Can disconnect battery from ECM to clear though not recommended for '90-'92 SD f-body setups.

RBob.

 

I start the thing up, it will run for about 15-20 sec, then die. It always puts a code 42 in the brain. reset the brain, start, does same thing. Code 42 does not trip the CEL, but will set a "invisable" code tell you jump the terminals, and count the blinks on the CEL.

 

Dale, you have the GM book, right? Did you run thru the whole chart to check out the wiring? Might have a wire with a break in it. You could do the wiggle test, too... wiggle the harness wires going to the coil and the spark module (NOT the spark plug wires!!) and see if the engine stumbles or dies.

And I assume you used the heat sink grease on the new module, right?

 

not another igniton problem. I have chased this damn thing till I was blue in the face. I finaly got it fixed. The plug going into the dist was twisted and not making a connection. I replaced it and everything was fine.

check out my post "help!!before I shoot my car." Just do a search. It will have alot of good advice.

Just remember, Do eveything by steps. Eliminate things one at a time and you will finally run it down.

good luck.

 

Did the search, message is here: https://www.thirdgen.org/techbb2/sho...hreadid=135870

 

Thanks for the info, but I found my new engine, and wont have to worry about this BS now.