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Hello there. I have a 1990 f 150 with a 5.8. So I gave it a tune up including the plug wires, and didnt bother putting them back in the seperator clip. I didnt figure it mattered. Now the truck has been running worse, idling and accelarating. In one of the other posts someone said that this crossing of wires could cause this. Is this correct? thanks guys.
7 and 8 tend to be the ones that cause trouble. They are the two back ones on the driver's side. Check to be sure they aren't getting too friendly, and maybe even let it idle after dark and look to see if you can find any spark jumping to ground where the wires are near metal.
Are you sure you put the plugs back in the correct order around the distributor? That could cause trouble too.
Eh, suggest the key word is 'could' - to which I would agree.
Depends on what is meant by 'crossed'. If you mean that the plug wires cross over each other instead of running mainly parallel to each other - maybe, but lower on my list of probabilities. If you mean that the plug wires have been crossed such that the wires are going to the wrong cylinders - definitely.
Suggest to verify your work - that the wires are correctly routed from the distributor to the respective cylinder. One of my most memorable 'gotchas' was that I had the wires landed 'one-off' on the cap.
im 99.9% sure the wires are on the correct plugs/distributer cap positions. also dont see any spark jumping wires in the dark. how big of a deal though do you think it is that the wires are not in the seperator clip? im running out of ideas on the rough idling. they are the somewhat cheapo wires, someone said that could be a problem. thanks.
i take it back, i went and looked at my receipt and did get the good wires , $53.00 nascar wires from schucks. im sorry i thought i had got the cheap ones. i didnt put any of that dialectic electrical grease on the plugs before putting the wires back on. maybe that could make a problem . thanks a lot,
Last edited by Michaelfealk; 11-11-2008 at 09:40 PM.
Reason: messed up
Do you have a chilton or haynes manual? If not you might need to pull up a plug wire graphic on the web... I'd re-check everything - make sure plugs are seated, make sure wires are routed from correct spot on dist to correct plug, maybe put some dielectric grease on the connections while you're at it.
It's gotta be something simple... if all else fails, let it idle, and pull each plug wire (from the plug) one at a time. It should make the truck run worse when you pull a wire. If one cylinder doesn't change things, that's where your issue is.
Just to be sure - you didn't change anything else? Have you checked to see if a vacuum line got pulled loose in the process by accident?
Your work might not be the problem. Other things could have happened. As just posted, run engine and pull one wire at a time. The cylinder that doesn't effect the engine running is the culprit. Possible spark plug got fouled during installation. Perhaps its just no good, cracked or some thing. We were just talking about fireing order on another thread. Don't know what you are running but here are the two fireing orders for the Ford V-8. 1-5-4-2-6-3-7-8 and 1-3-7-2-6-5-4-8. And yes, there was a TSB about plug fouling due to incorrect positioning of the wires in the clip securing to valve cover. Didn't understand the full engineering of it as it didn't have an instant fouling reaction, took a little time to foul the plug. Anyway KISS, (keep it simple stupid), and boy have I sbeen stupid at times. Retrace your foot steps and you'll get it right.
I guess there's one other thing that's so obvious it took a day to soak in...
Did you gap the plugs? There is an emissions sticker under your hood that will tell you the proper gap - don't take the parts counter guy's word for it.
And, like Bill said - could've fouled a plug on the way in, could've cracked one if it was torqued too tight (or dropped on the driveway), who knows. I'd still recommend pulling one wire at a time from the plugs with the engine idling to see if one doesn't change the idle.
Don't try to pull wires from the distributor to make it easier - it'll shock your ***** off!