I need some quick help with my truck not staying running.

[joegreen]

I say quick help because i am on spring break and i only have until monday when i need to make my 40 mile round trip to school. So anyway, I was driving my truck the other day and all of the sudden it just cut out like someone hit a switch. I managed to get it restarted and got to a pull off. I could get the truck to run but within a couple minutes to a couple seconds it would just cut out. I have a code 43,45,51. I just tried to start my truck but because the battery is so dead it cleared all the codes from the ecm. so other codes may have popped up when this happened but they might have gotten cleared because i kept trying to start my truck that day. I am going to take off my icm and get it tested at the store just in case that is the problem. Also another thing, the day before this happened i was driving home and the truck kind of missed once or twice but then was ok. The miss occurred when my driveway was in view so i only drove like half a mile more after the miss occurred before i parked it.

[RobertISaar]

the 51 strikes me as a possible ECM/PROM/CALPACK failure.

[joegreen]

i do have the 1227747 ecm and i am running a 27sf512 chip. i made sure the chip was seated properly. I just purchased the ecm from a junkyard about a month ago (doesn't mean its not bad).

[joegreen]

So i went to autozone and had them test my icm a lot of times. I held my fingers on the heat sink until i couldn't hold them any longer then we did a few more tests after that. I think the icm is fine. I have my truck running but i dont want to drive it anywhere. I took out my chip and erased it and re burnt my bin. I am going to hook up my laptop now and see if i see any codes. Also when the truck is idling if i listen to the exhaust it keeps making very tiny pops constantly.

[joegreen]

i shut it off and pulled the ecm fuse to clear the codes and now it wont restart. it just turns over.

[sturgillbd]

Do you get the flash of the CEL when you first turn the key on? If so, do you have spark during crank?

[joegreen]

ok so it restarted after sitting for a while. i have no codes. I am letting it idle and i will check on it in a minute

[sturgillbd]

While it is running, lightly tap on the ecm case. If you have a bad solder joint etc, it may cause it to show up. Intermittent problems can be hard to find.

[joegreen]

ok, so i gave the ecm the good ol one two for like 30 seconds nothing crazy and everything seems fine. The truck has probably been running for a half hour. No codes revs up ok. Its still running.

[joegreen]

i just shut it off and started it again. the code 51 could be because i removed my chip. Would it set that code even with the truck off but with power to the ecm? also the cel stays solid withe the key on engine off. When i start it the cel goes off.

[sturgillbd]

The only thing that would really concern me was your error code 51. The other codes could be loose connections etc. One more shot in the dark... Have you ever looked at the spark plug wires at night? If you have any leakage in the insulation on the plug wires, they will have a corona glow or you may actually see them arcing to ground. That will cause a miss and can also drive your ecm nuts. As for the error code 51, I have never pulled the chip with the ecm having the constant power on it. Usually you disconnect the battery before removing the chip.

[joegreen]

Its dark in ny now. Ill check that.

[joegreen]

no leakage of any kind from the wires. Also it starts up just fine. this concerns me because just before it would not restart and now its like everything is fine and i haven't touched a thing. Also not sure if its a coincidence but i have no headlights either ugh. I am done out here for tonight.

[sturgillbd]

If you can do a ten minute datalog and post it, I will look at it. Are you still getting lots of data errors?

[sturgillbd]

Sorry. Just saw your edit about headlights after refreshing the page.

[joegreen]

Yeah i am getting so many errors its crazy. I only get questionable data every like 20 seconds. On the plus side i know we were trying to work through the whole error deal with the harness being close to the plug wires and all but i am going to buy a new harness pre made, YAY, although it wont be installed for a couple months.

[joegreen]

Any thoughts on my next move? Thanks for all your help so far.

[jim_in_dorris]

the 7747 is known to have issues causing a 51 code to be set. I have seen some advice on thirdgen and fullsize chevy about using the moates socketbooster to correct that problem. I just replaced my ECM when I had that issue and solved the problem. Also be aware that your miss could be a worn distributor.

[joegreen]

I looked over everything and saw nothing out of the ordinary. I checked ground with my dvom from the battery to the engine and body and everything read the same voltage as if i was touching the two posts on the battery.

[sturgillbd]

Have you driven it since the night you found your headlights not working? If you can drive it and datalog, even though you are getting errors, it may show something. It is hard to diagnose with such little information to go on. If I remember correctly, did you install a zif socket into the ecm?

[joegreen]

Yes i did install just the modified zif.