My work 2005 3V 5.4L Expedition recently did the same thing. Only when under light load, and only when in 4th (OD) with the tq converter locked up. The tech hooked up a scanner and went for a ride w/me. Cyl #1 misfire. It only flashed the check engine light when I got it to misfire under heavy load (floored it). When under light load, the misfire made it buck really bad, but even then didn't set a code.
ib516 wrote: My work 2005 3V 5.4L Expedition recently did the same thing. Only when under light load, and only when in 4th (OD) with the tq converter locked up. The tech hooked up a scanner and went for a ride w/me. Cyl #1 misfire. It only flashed the check engine light when I got it to misfire under heavy load (floored it). When under light load, the misfire made it buck really bad, but even then didn't set a code.
Engineer9860 wrote: When the spark plug fails to ignite the fuel/air mix, the exhaust will have an excess of hydrocarbons in it. This will be registered by the O2 sensor as a "rich" condition.
The O2 sensors do not read hydrocarbons. They read oxygen, hence the name oxygen senors.
I knew that, I have an excuse for my mistatement......It was late, and I wuz tired.
Update: Just put the new coil on (had to go pick up a 7mm socket, wouldnt you know thats the one socket I could not find in the toolbox). Coil does not appear to have fixed the problem. I just put new coil on (and disconnected battery for several minutes to clear out trouble code), its still missing.
While engine was running, I removed the connector/wire from the coil I had just put on. Engine kept on missing, no change (did not get any better or worse). Sooo, I'm thinking its either the plug, or a very dirty (or defective) fuel injector.
..Think I'm going to go pull a plug out, see how it looks, maybe replace it if it looks bad. Failing that, may be time to try some good Techron fuel injector cleaner. Failing that, I believe I'm done, will be time to let the professionals look at it.
Edit: Hold on! Was just 'bout to pull the coil back out, when I noticed, the wire going to the fuel injector for that cylinder. Its chaffed to the point one wire is broken completely off! That injector isn't getting any current!! No wonder that cylinder won't fire, the wire going to its injector is broke!
Now, to figure out how to fix this wire problem...Back in a bit...
Will
* This post was
edited 06/28/08 09:44am by willald *
..Continuation of last post, and conclusion to this issue:
Indeed, the problem all along was the chaffed wire going to that fuel injector. A few pieces of #14 gauge wire and electrical tape later....Now, the truck runs like brand new again.
Thanks to all, for your help, comments, education, etc. on this. I've learned quite a bit. Indeed, I wasted $60 on a new coil, but not really - now, I have a spare coil for when one really goes.
The wire I repaired, had been routed such that it was in a very sharp bend/curve. Appears that with time, the wire weakened around that sharp bend, and eventually severed in half.
I think I'm still going to run a bottle of Chevron fuel injector cleaner through it, make sure all the injectors are good and clean, regardless. And, Don's suggestion 3 pages ago was a good one - in spite of fuel prices, we're probably just going to have to use this truck more.
Will glad you got it fixed!!! Here we are talking about complex everything is and it's nothing more than a chafed wire! Good news is the truck is back and no trip to the dealer!!!!
willald wrote: ..Continuation of last post, and conclusion to this issue:
Indeed, the problem all along was the chaffed wire going to that fuel injector. A few pieces of #14 gauge wire and electrical tape later....Now, the truck runs like brand new again.
Thanks to all, for your help, comments, education, etc. on this. I've learned quite a bit. Indeed, I wasted $60 on a new coil, but not really - now, I have a spare coil for when one really goes.
The wire I repaired, had been routed such that it was in a very sharp bend/curve. Appears that with time, the wire weakened around that sharp bend, and eventually severed in half.
I think I'm still going to run a bottle of Chevron fuel injector cleaner through it, make sure all the injectors are good and clean, regardless. And, Don's suggestion 3 pages ago was a good one - in spite of fuel prices, we're probably just going to have to use this truck more.
Thanks again, to all that posted here.
Will
If the wire to the injector was indeed completely broken you would have had more than just the misfire code set. There would have been an injector circuit fault code set also. This is why I asked what exactly the codes were when you had the Autozone guy pull them. You can buy a generic OBDII scan too for under $100.
rlh6805 wrote: If the wire to the injector was indeed completely broken you would have had more than just the misfire code set. There would have been an injector circuit fault code set also. This is why I asked what exactly the codes were when you had the Autozone guy pull them. You can buy a generic OBDII scan too for under $100.
Well, like I said, I didn't get to see all the specific trouble codes. But, yes, I can assure you, one of the two wires was completely broken. The other one had a few copper strands left hanging on, but the other was completely in two. I did snap a picture of the broken wires just before starting to repair it, will try to upload that picture later and post it here. Didn't come out very good, though, so not sure you'll be able to tell much.
Dont know much about how to use those scanners, maybe the guy at Advance just pulled up the two most recent codes, didnt see the one for injector circuit. Since I've reset the computer now, impossible to say. Had I seen a trouble code indicating injector circuit fault, I would have looked closer at the injector and the wire to it, probably probably would have found that loose wire right off the bat, and never bought the COP. No problem, though. Good to have an extra COP handy now, for when/if one goes in the future.
I *am* going to start looking at scanners, though, and either buy one, or put it on the Christmas list.
Will
* This post was
edited 06/30/08 11:58am by willald *
Will, if you are serious about a scanner I would also consider investing in the Helm manuals also as these provide you with the trouble trees for chasing down each code the PCM is capable of producing.
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