If you have read my posts you know I am fighting a used engine install. 1993
5.2L 4x4 have changed all sensors, new cat, new muffler, new wires plugs cap rotor. new radiator/hoses.

Truck is now constantly pinging/preignite at all speeds. After approx 10-15 miles the temp gauge approaches hot and the engine coughs sputters and dies. I do not believe the engine is in fact overheating, new 180 deg thermostat yesterday. After dying it acts like no spark for a period of time (sometimes 1-2 minutes sometimes 5-10 mninutes) then it starts and usually runs as before. Generally regardless of how long it was dead the temp gauge goes back down to about 1/3 of hot, then it seems to stick there or after a few minutes it may crawl back to midrange. Eventually it bogs down and dies again.

Question is: What is the likelihood of the common ground through all sensors (I believe it is light blue/wht) shorting and causing all this?

 

I don't know about your ground question, but do you know if the heat is affecting your sensor wiring at all? I had a similar problem w/ my new crank sensor, the wires going to the harness began to melt and would occasionally drop entirely... stalling the truck, and then it wouldn't start.

Doesn't sound like heat is the real problem here, but I figured i'd ask, some of my problems wound up being heat related, and yet it hasn't overheated yet.

 

it sounds to me like its your computer. I know mine did this on my 87 3.9, it would die for no reason and wouldnt start back up. even though theyre 200 bucks. i'd try it

 

Have you checked the timing out? Sounds to me like you are out of time a bit...That would cause the overheating and the preignition. Does the engine in fact have no spark or are you just thinking that?

 

I'm pretty sure you can't adjust the timing, as that is all electronic on the EFI magnums.

 

I have not replaced the timing chain. That was last on my list (figures). Repalced pickup sensor today and both engine coolant sensor top caps. Got a little better for a few but still preigniting and dying. Tell you what though, when I figure it out I will have a "new" truck. And it now sounds and runs great other than the major problem.

Because I am in the sticks everytime it dies I haven't confirmed no spark other than taking off the coil wire and checking against coil.

 

Taking it to mechanic tomorrow I have had all the fun I can stand.

 

You are right, but it sounds like the timing chains worn to the extreme, the distributor isnt lined up, or like someone else said the computer is muffing up.

 

The preingition was the timing. Distribut was off 7 Degrees and the computer would kick it 7 more degrees, now it is timed dead on and the preignition is gone, however I am still showing overheating and now I believe it really is, and it is still shgutting down with no spark for a short period.
I found a cut wire going to the oil sending unit and fixed it hoping my problems were solved. NOOOOOOOO such luck.
I am still overheating and my oil pressure drops at same time, one person suggested fan clutch could be problem?
Where radiator is new, thermostat is 180 deg and new all hoses are new coolant temp sensors are new, thermostat is opening anybody got a good feel if just the fan clutch could do this or would it take both the fan clutch and waterpump?