Cylinder #6 misfire

[timberwoof]

Hey guys. I searched a little bit but came up empty. Having a problem and it's a little, but not much, frustrating. Had a bad hesitation about 3 weeks ago and finally had an engine light come on. Said misfire of cylinder #1. It was time for a tune up so I went ahead and did coils and plugs. I've done them in the past and didn't break any then, and didn't break any this time as well. Thank heaven. Now 3 weeks later there is a hesitation again, but this time it is saying cylinder #6 misfire when the code pops up. These are brand new coils and brand new motorcraft plugs. I checked the harness but didn't see any fraying so I'm wondering how I can test the conector to the coil and maybe the cool itself. I have a volt meter but need to know what I'm looking for when I start trouble shooting.

Any help is greatly appreciated.

 

[46L281GT]

What brand are the coils?

 

[docraymund]

Get or build yourself a noid light tp check coil and injector pulse. Check coil and injector tabs for loose fit. Check fuel injector for continuity and borrow a compression tester for #6. A repair manual will come in handy.

 

[timberwoof]

Ok this is starting to piss me off. I moved the coil to cylinder 1 thinking if it was the coil it wild misfire cylinder 1. Nope still misfire cylinder 6. I replaced the connector because it liked a little black, nope still misfire. Right now I'm waiting for the engine to cool down to pull the plug and look at it to see the condition of it. When I put it in it was brand spanking new, hopefully it's not fouled.

Is there anything else I should be looking for? What is there before the coil, or does it come straight from the PCM?

 

[Habbibie]

Remove the spark plug and see, if it's not the reason you think then insert a long stick inside the cylinder through the spark plug hole, make sure that stick has some type of cotton or a piece of towel at the end of it and put it in the cylinder and move it around, pull it out and tell me is the piece of cotton have any oil or water on it? If yes it's a head gasket, if not then you're safe it's not a head gasket.

 

[timberwoof]

These are the two codes I got today.

Oops sorry the pic is upside down.

 

[Bedrck47]

********

 

[timberwoof]

Damn I thought I had it fixed after several weeks but, nope. Same code came up. Is there something other than the computer which sends the signal to the coil, telling it to spark. I really don't want to start tracing wire. That is going to be a task.

 

[jeff kushner]

I got a pdf copy of the 03 manual.....don't know what model you have but if it can help, let me know and i'll hook you up with a copy.

jeff

 

[grantpa]

Had this same problem-P0303 and P0301. Now P0307. The first 2 were due to bad boots and corrosion on the spring-to-terminal conn. Pulled the boot and spring, wire brushed the terminals, replaced the boots and.....NO CODES!

 

[timberwoof]

Ok big update! Sorry it's been a couple months but I figured out what was wrong. Did this back at the end of November. I pulled out my volt meter and started checking wire to see if I had a short or broken wire in the harness.

Well problem was a wire was broken. I don't know how it happened but I traced it to the signal wire of cylinder 6. The power wire was fine. I fixed it and it works great now.

Only other problem I had since, was a coil going out on cylinder 8. Did a change and it's running good now.

 

[LEOL]

glad you got it figured out. If youre so obliged, providing a little more detail on how you tested the wiring would be great for others looking for similar help in the future.... particularly things like specs for signal readings and such, is good info.

 

[timberwoof]

i used a volt meter to check for completion of circuit. When you are looking at the pcm from the front of the engine. The left side connector is the one which has the signal wires which go out to each coil. If you take off the connector and look at the the face of it the top left holes are all signal wires to the coils.

To find this out I actually took off the rear plastic piece of the connector and marched up the wire colors to the ones on the coil. I tested completion of circuit with a couple of the other coils as well to confirm they were actually the signal wires.

The one going to cylinder 6 was not giving me a reading proving there was a break in the wire. I pulled a little on the wire itself and sure enough the wire came out of the loom, broken about 6 inches away from the connector.

I soldered it back together and used shrink wrap to keep it snug and dry, and the. Buttoned everything back together.

When 8 was giving me problems, I did the same process to rule out another bad wire but I had readings through them so I just replaced the coil.

No problems since.

 

[LEOL]

Nice! thanks for that. it may actually be of help to me, as im in current project on similar diagnosis. Im thinking ill probably check for both continuity as well as resistance because i feel i may have an intermittant issue on my hands, and i dont really want to shake the wiring harness around trying to test it, thats just asking for (more) broken wires. lol.

 

[Snag]

Good write-up timberwoof.
LEOL, I was thinking of you as I read through this. You "might" be having the same problem.

Strange a wire would break that far up the harness. I wonder if that engine has had top top end work and wires yanked around.

Timberwoof. Thanks for following up. Good info for future references

Gary

 

[LEOL]

my thoughts exactly, snag.