COP/misfire problem!
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Freshman User
Joined: Mar 2008
Posts: 32
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COP/misfire problem!
Ok... I have had plenty of issues with this truck, and if it doesn't get better soon, its going to find the fast way off a bridge... lol
On to my question....
I recently changed the timing chains, and pretty much immediately afterwards the truck started idling like crap. Engine light was on, took it in to see what new codes I had, and it says that Coils 3 and 5 are not working right. Now, I do believe in bad luck, and I suppose this thing could kill 2 1 year old coils at once, but I'm not so sure. Before I shell out the bucks for these, are there anythings that I should check first? the looked like they were plugged in just fine(I had to unplug most of the coils to get the chains on). I am mostly wondering what the resistance should be on the coils, and which cylinders are which....
One other thing... this thing had a MASSIVE oil leak, and before we began on the chains, we washed the engine. Didn't use a power washer, only a garden hose and a few cans of degreaser. Is it possible that water has gotten in there and would still be there 2 weeks later?
On to my question....
I recently changed the timing chains, and pretty much immediately afterwards the truck started idling like crap. Engine light was on, took it in to see what new codes I had, and it says that Coils 3 and 5 are not working right. Now, I do believe in bad luck, and I suppose this thing could kill 2 1 year old coils at once, but I'm not so sure. Before I shell out the bucks for these, are there anythings that I should check first? the looked like they were plugged in just fine(I had to unplug most of the coils to get the chains on). I am mostly wondering what the resistance should be on the coils, and which cylinders are which....
One other thing... this thing had a MASSIVE oil leak, and before we began on the chains, we washed the engine. Didn't use a power washer, only a garden hose and a few cans of degreaser. Is it possible that water has gotten in there and would still be there 2 weeks later?
FTE Legend
Joined: Jan 2006
Posts: 37,918
Likes: 178
From: Princeton, BC
I guess you could take those two coils and move them to different cylinders. If the missfire changes cylinders you have a pretty good idea its the coils. I just had one of mine go and moved it just to confirm. Other than that I can't offer much more assistance. Someone with a little more knowledge should show up shortly.
Hotshot
Joined: Jan 2004
Posts: 19,763
Likes: 1,082
From: St Louis
You probably got water down in the plugwells and are shorting out the spark.
Pull the suspect COPs and dry out the well. If you're lucky, the COPs didn't get damaged (don't hold your breath).
Steve
Pull the suspect COPs and dry out the well. If you're lucky, the COPs didn't get damaged (don't hold your breath).
Steve
New User
Joined: May 2007
Posts: 10
Likes: 0
Water can get in past the boots and into the spark plug passage. The previous owner of my Expedition must have washed the engine at one time. When I changed the plugs a few were rusty like water had been in there. Pull all the coils and blow compressed air in the there. Could be you have some water in there causing some misfires.
Hotshot
Joined: Jan 2004
Posts: 19,763
Likes: 1,082
From: St Louis
If it was forced in under pressure, the boot still seals well enough so it can't evaporate (no vent).
Steve
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Postmaster
Joined: Nov 2006
Posts: 4,517
Likes: 3
From: SE Wyoming
AS one of the first replies said always move the COP's to different cylinders and see if the misfire follows. Obviously if it does the COP is bad, if it doesn't you have a plug or injector problem, or even a bad harness at that cylinder.
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