Shuts off and will not restart, code 42

15 min still running

Ok coming up on 30 min running um the only thing I did differsnt was lightly tapped about 15 times all over the ECm

Ran truck 45 min drive truck ten min came home shit off off for five min cranked it right back up, not sure it its a bad ECm or bad ECM connection but for
Now it’s not really a hard break n my mind so I’m going to let
It
Run and see what happenes. Thoughts??

I understand then oik pressur sending unit is tied into the fuel circuit as a secondary shut off point if oil pressure isn’t lost um but not does that mean the sending unit has to b 100% inoperable??? Mine is operational just gives false reading IF u shower down in the gas pedal

Yea nevermind it sat for an hour and now it won’t start so back to square one.

Ok, thats the trouble with intermittent issues.

The oil pressure switch will never cut it off, just a bypass in case the relay fails.

Roy

I don’t know what
To do next

This is why you need some help from someone who has the test equipment to test it. Also, someone who has knowledge of the older systems.

Roy

I bet its a 500.00 fix

You could just get the diagnostic and then repair it yourself.

Roy

I’m gonna change out the distributor

Why are you doing that??

Well for the drawing that I saw the purple and white wire coming out of the big plug on the ignition control module is the ground that goes back to the computer and grounds the drivers they give power to the igniters skews me the injectors so when I get home I’m going to stick a needle in that wire and put my test line on it and crank it over and if there’s no fuel no ground and no fashion then I know that that wire is not grounding out in the computer I figured for another 50 bucks I could get a whole new distributor

OK let me clarify my last statement when I get home here in a little while I’m going to unplug the four wire plug on the back of the distributor skews me the four wire plug that I was on the ignition control module the purple and white wire I’m gonna ground that wire out with the key on the injectors should fire if they do not fire then I got an ECM an issue if they do fire then I got a control module ignition control module issue SO MORE TO FOLLOW

I was finally able to find the right schematic online is the reason I’m taking this course of action

The injectors will pulse if you tap it to ground many times. just grounding will only give it a brief shot. if you tap it many times, then see if the injectors fire

Roy

Correct, I’m at the point where I have fire always now it’s hetting the fuel and the common part is the ICM BUT the ECM also plays a part so I gotta delet one and this isn’t the only test I can see that would do away with a part of an intermittent problem, Ian my thinking process correct

Yes, try it as a test

Roy

Works bad ICM as u said to become with y mine tested and still tested good not sure

bad ICM?? did you replace it

Ordered it, I had ordered one last week that came in DOA and then had my original one tested but it tested good so I chased my tail for a min well then I was tryin to find a schamatic and some time to fix the truck well when I finally found the drawings I could do better trouble shooting which lead me back to the ICM, grounded out the right wire the injectors pulsed to that tells me in fact the ICM is bad so I ordered an AC DELCO one this time fingers crossed this is a good fix

keep me updated

Installed new part started right but I may have crossed the wires for the luck up clip cause when u drive it the rpm bounces around a little like it’s hunting and I know one of those wires go to the tach if I remember right

If you mixed up the tach wire and the power wire from the ignition switch, it would not run.

Roy

Wires were good I think my caps bad cause I remember scraping the calcium off it early last week, if I remember right, problem I have is it’s a truck that I don’t drive very often so I don’t try to get it fixed like now so I do things and forget what I ha have one lol um it has a new rotor cause the center price broke off on me but. I new cap, it dials great and does drive it just has a small miss or hesitation like it’s not hitting all cylinders but yet not that rough so I’ll change cap amd aee

Yes ur right lol I swapped then and man did it buck lol

check your cap again

Roy

Yea that what I’m going to do, I had taken it off and must have hit the metal peice in the center of the rotor so I changed that out not even thinking about the cap and I have always changed them together so I’m real sure that’s the problem, today I have plenty of time to fix or drag it to the local shop lol

Ok, keep us updated

Roy

Center price of the cap had slung open so the context er was floating around n there um I bought the truck from a friend and by the way the spark plugs look I’ll do them and wires next and I think I’ll
B as good as I was when this whole started, Roy that’s for all the help I’ll saves this conversation and picking up if I have any other questions...... u know desiels as well

Yep. grew up with the 5.7, 6.2 and 6.6 engines

Roy

Not think I have been told the right info, last year had a code for 7-8 glow plugs bad so I changed them all with after market plugs, not I still have codes for those two and pending codes in all the other ones?? Been told wiring issue or a glow plug control modual and none of that make seems to me I don’t have a code for the mondual just the plugs

07 6.6 duramax

Ok, once you have more than 1 glow plug fails, you need to replace all of them along with the controller. the controller fails due to the glow plug shorting directly to ground

Roy

Ok, been told GM do bad with aftermarket plugs um I think that’s a scam but that’s just me seems crazy to spend another 200 after u have changed the plugs just to fix the original problem

The quality of the glow plugs is important. I use GM parts when I replaced them. The module is a must to replace

Roy