HELP...with code 42, truck won't run...

[grizzlyoffroad]

I'm in a bad way guys. I tried everything I could think of so I took it to the shop....they can't figure it out either. The truck starts, but has no power, backfires, sputters, then eventualy dies. The only thing we can find is it throws a code 42 which is Electronic Control mod....If I remember correctly. You can clear it, but it comes back immediately. I have changed all the electrical: wires, plugs, distributor, coil, etc. and tried many different timing setting. The shop has changed all questionable sensors, wires and even the computer...NO LUCK. Any ideas guys? Anyone ran into this? Please help!

PS. 1995 chevy K2500 with built 454, hypertech chip, many mods, but it was done 6 years ago and ran great...uptil now.

 

[Russell]

How is the knock sensor? Any shorted wires anywhere? EST bypass plugged in?

 

[grizzlyoffroad]

I'll check it, thanks. Anyone else have ideas?????

 

[dyeager535]

http://www.thirdgen.org/techboard/electronics/291496-error-code-42-a.html?highlight=code

Some of the wiring might be off a bit on the '95, then again maybe not.

 

[diesel4me]

ECM ground..

I've seen a few trucks with similar symptoms as yours..2 turned out to have poor grounds at the ECM...(computer)..we ran a new wire right to the case of the ECM and to ground,and both trucks are still running good..they had been to several other garages,and had been given up on--until my friend discovered one truck would die as soon as he touched the ECM with it running..a bad wire between the power source to the ECM and the battery can cause this also..one that is corroded or has just a few strands of copper making the connection--heats up and causes excessive resistance,cutting the amount of amps to the ECM..

We also had one truck that the "Prom" inside the computer had loosened up,and was barely making contact with the curcuit board--took us weeks to figure that one out--then there was one truck someone swapped in a different computer,that didn't "jive" with the engine and tranny(a V-6 ECM and a 350 motor!)..that took awhile to discover too..funny thing was the truck ran decent for awhile!..then started acting goofy,you couldn't even drive it..