wreckedrex

So my 93 pickup chose last night to take a dump. She bogged really hard leaving a light, lost power, sounded like crap and wouldn't idle. I limped it home, shut it down and tried to re-start hoping it would fix itself She fired right up, but ran like hell and would die when returning to idle after cracking the throttle. Not surprising, but disappointing. Next I checked the codes and it flashed 14, which tells me that the ecu isn't seeing signal from the ignitor (right?).

Here's where it gets sorta strange: After staring at it for a while longer and looking into how to test the ignitor/coil/dizzy I tried to start it again, this time with the jumper in the diagnostic port. It ran great! Like, really great, better than it was before the screw up. Just for giggles I ran it around the block and it ran better than it ever has in the time I've owned it. That was cool and all, but I didn't really like the CEL flashing at me and I'm not really sure if driving it with the jumper in is kosher. So I pulled the efi fuse to reset the code, reset the idle and timing while I was in there, pulled the jumper, crossed my fingers and turned the key. Success! Sort of... It was back to it's normal self, and still ran better with the jumper in. With the jumper out the idle droops, she looses a bit of power and runs a touch rougher. Weird. Any ideas? I was thinking maybe something with the knock sensor? From what I've been able to find it won't throw a code unless there's an electrical fault, if it's working and pulling timing you won't see it. If it's pulling the full 8 degrees that would explain the idle droop and loss of power. That is assuming the the ecu ignores it when the jumper is in place, I'm not sure it that's the case but it makes sense that it would be... It just occured to me that I could probably verify that with the timing light, I'll do that over the weekend.

92dlxman

if your computor logic is similar to my 22re's, running with the jumper in place with any throttle input will render the jumper innefective and it will go about running its merry way as if the jumper were not there. that is why you cannot set base timing with a bad tps or with any accessory on that would cause idle up. the code you see while driving it, jumper in, is a code warning of those potential problems.

now to your 14: sounds wayyyyy too much like my truck was: RANDOM!
to fix, i verified proper grounding points, seriously that alone helped, just looking at them and poking them like i know what im doing what really did it though was a re-wrap of my insulation around the wiring harnes from ignitor to computor. inspect all splices as best you can without removing the sticky tar stuff. good tape is key

wreckedrex

Now that you mention it I think I've read something to that effect... Probably a placebo, but i'm curious enough to check w/ the timing light. I'll poke @ the grounds and check the wiring to the ignitor, shes got >220k mi on the clock so old crusty wires are definitely a possibility.

wreckedrex

So I poked around at the grounds and harness this afternoon and found an iffy ground (left head to apron) and a possible short in the harness where it runs by the injectors under the intake manifold. The wrap had disintegrated and left the bundle rubbing against a metal tab that was probably supposed to be retaining the harness. I ran a new ground and glopped some liquid electrical tape onto the suspect portion of the harness and she runs great. It's always felt really thrashy and rough over 3k rpm, now it feels fairly smooth to redline. Quite a difference. I'll have to pull the upper manifold off to really re-wrap the harness, but I'm in the middle of a move so this will have to do for a little while.

92dlxman

thats awesome man im really happy it seems to be working out for ya! keep an eye on it, and when there's time, get er nice an tight!