1993 chevy suburban
2500 4x4 7.4 454

I was driving it and all of a sudden it started running like it was out of time long story short i changed distibuter, cap and rotor,wires, plugs, coil...still nothing!!!! it will start and run(like crap) for a minute and then just die....the codes it is giving me are 42 and 43 anybody have a clue what to check next?

One of those codes is for the ignition circuit and one is for the knock sensor circuit. They are both somewhat related. The knock sensor tells the computer when to retard the timing and the ignition module does it.
You could have a problem with any of the 3 of those components setting both codes. I would start with checking out the knock sensor.




78 Corvette Pace Car For Sale-18k mi orig-Florida




(This post was edited by Hammer Time on Nov 15, 2009, 1:15 PM)

 
LIFE IS SHORT GO FISH
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(This post was edited by re-tired on Nov 16, 2009, 11:45 PM)

There are no wires going to the knock sensors....any chance you know what color wire goes to them? I cant find the knock sensor on my wireing diagrams

The knock sensor is in the right side of the block, right in front of the starter. It's a single Dark blue wire.




78 Corvette Pace Car For Sale-18k mi orig-Florida

is it possible the truck can run fine without the wire hooked to the knock sensor? I have searched for the harness and or wire all over and cannot find one....if so what else can i look for

It was there when they built the truck




78 Corvette Pace Car For Sale-18k mi orig-Florida

does it trace right back to the ecm?

If you have the 4L60-E transmission, it's at pin B15 of the ECM
If you have the 4L80E transmission, it at pin D5 of the ECM
On a manual trans, it's not showing me

Have you found the sensor itself?




78 Corvette Pace Car For Sale-18k mi orig-Florida

What i am saying is that The knock sensor doesnt have a wire hooked to it and I don't know how it would just fall off and not just be dangling there...so i would like to know where to trace it from so if need be I can run a new wire. I appreciate any further advice

yes i have

another dumb question...how do i figure out what transmission i have?

78 Corvette Pace Car For Sale-18k mi orig-Florida