94 miss at idle finally fixed !!!!!! found problem

[silver100]

i finallu got my 94 silverado fixed , i decided to open my hood at night in the dark to see if any fire was jumping . i was hoping maybe the coil was jumping fire , what i seen was fire jumping up and down the new premium napa lifetime wires that has been on for about 2 weeks . i had 3 plug wires jumping fire all on the passenger side . i went and bought a new set of accel superstock 8 mm wires and a set of stock ac delco plugs and triple checked the gap to 0.35 and i also installed a new coil also . that took care of my miss and my truck runs as good as new . i was amazed at the power it had .so 2000cayukon try looking under your hood at night and you may see the same problem here . but all is right . thanks for all the imput from evry body , also i found don't ever run autolite in a chevy , big mistake . i will only use stock ac delco that the truck calls for from now on . thanks silver100

[2000CAYukon]

I am glad that you found your problem! I did look at night a while ago but will try it again. I replaced the dist gear but I still have a miss at idle.

//2000CAYukon

[2000CAYukon]

My luck is not as good as yours. No sparks at night. The timing is bouncing around as much as 20 degrees. If I disconnect the EST and also disconnect the MAP sensor, the timing does not seem to be moving. Eventually (1-2 minutes) it will die with the MAP disconnected. The MAP is new plus I have had the original and the one off my car in it. All acted the same.

The +5 Reference and Ground at the MAP are good. I think that this has to be the ECM (original) and is probably my next step.

//2000CAYukon

[silver100]

2000cayukon ,

my luck is not as good as i was hoping on my truck , the same miss came back today . i rechecked the timing and made sure it was set on 0 and the miss came back tonight . . my next question is why did it go away for a few days with the new wires and coil and plugs and then come back . also i was wondering about the timing . is it possible that the mark could be off on the pully and i should maybe do a top dead center time to make sure that i am getting it right . i am out of idea's . let me know how the new ecm turn's out 2000cayukon . thanks

[2000CAYukon]

Originally Posted by silver100

2000cayukon ,

my luck is not as good as i was hoping on my truck , the same miss came back today . i rechecked the timing and made sure it was set on 0 and the miss came back tonight . . my next question is why did it go away for a few days with the new wires and coil and plugs and then come back . also i was wondering about the timing . is it possible that the mark could be off on the pully and i should maybe do a top dead center time to make sure that i am getting it right . i am out of idea's . let me know how the new ecm turn's out 2000cayukon . thanks

Wow, that sucks! I have not replaced the ECM yet. Will probably order one tomorrow on the way to work. At this point, I can't think of what else it could be. I am going to try a vacuum pump on the MAP (constant vacuum) to see if the timing still jumps around. I know with the MAP disconnected, the jumping stops.

You already tried a different ECM, right? Here is a good article on checking the ECM grounds: http://www.cardone.com/English/Club/...%2077-0008.pdf

I will post later when I try the new ECM.

//2000CAYukon