P0302 cylinde #2 miss fire?????

[wmr95]

I had a P1518 for the IMRC stuck open, I found the linkage laying on the intake b/c of the retainers being broken. Replaced them and now I have a P0302 for #2 cyl missfire. I found a lil info on this sight for past probs but no definitive solution. Any help would be greatly appreciated
Thnx
rob

[wmr95]

OK I'll talk to myself, I took out the ignitin pack and did the ressitance check, all was good with IAW the Haynes book. I did notice the #2 wire was black around the end for the ignition coil. I'll keep going and eventually get to a solution
thnx

[tripletdaddy]

Sounds very suspicious like maybe your #2 wire might be shorting. You can resistance test them, but I don't think that it will prove with certainty that it is bad unless its open. Try moving your #2 wire to another cylinder to see if the miss move with it or use a spare good wire in its place to see if it solves the problem. Did you try running the engine with the hood up in the dark to see if any sparks jump from it? Plug wires should be 250 to 600 ohms per inch, 3000 to 7200 per foot.

[wmr95]

Thanks for the info, I did try to check the resistance on the wire last night but it didn't show anything. It is either open or my meter sucks. I am going to try and do a wire swap tomorrow and see where things go from there.

[wiswind]

A problem that comes up with both the wires and the ignition coil is arcing through the insulation, or a crack in the insulation.
With the coil, a crack can develop in the epoxy body and arcing can take place through there.
Resistance checks could be fine, but arcing still happening.
The look under the hood in the dark with the engine running can help you find that.
New wires might be a good idea, and if that does not solve the problem, a new coil pack.

Of course, I would also run Berryman's B-12 Chemtool in the gasoline, as I have had several situations with misfire that ended up being dirty spray ends on my fuel injectors.
The first time for me was on cylinder #2.
I pulled the spark plug on cylinder #2 and it was dry and cleaner than 2 other plugs that I pulled.
That indicated to me that my problem was fuel related and not spark related.
Of course, that was after changing the spark plugs, wires, and coil pack....and a lot of other things.
Once it got bad enough to light the CEL and get me to the cylinder, I had the problem solved the next day.

[wmr95]

Thanks for the help, I am going to look into it this afternoon. I'll get back with what I find out.
Thanks again
Rob

[wmr95]

OK I put everything back together to look for arcing and WOW, no arcing, but the whole engine looked like it was going to vibrate out of the car. I hooked up my scanner and got an P0351 code. The engine died and I tried again with the same result. Not really sure where to go from here but it looks like a coil, wires and plugs to start, any suggestions?????????????????????????????????:bangh ead::bangh ead::bangh ead::bangh ead:

[wiswind]

Use care to make sure to get the spark plug wires connected to the correct terminals.....VERY easy to get them switched.

If the plug wires are not practically new.....I would replace them as well.
When removing spark plug wires, do NOT pull the wire...but grasp the boot.....turn the boot on the terminal (coil) or spark plug a bit in each direction to break it free, then pull on the boot to remove.

[tbirddmnd]

wmr95 - dunno if this helps but my misfire P0303 turned out to be a bad coil. I changed all sorts of sensors and took the top intake off when I didn't need to. Try a new coil pack, plugs and wires. Easiest to remove the plastic cowling to get to the back wires/plugs and coil pack. TRUST ME on that! You'll have loads of space once that's out of the way. You'll need to remove the wipers with a 15mm socket. There's a plastic cover over the arm pivot ends that flip up easily.

[tripletdaddy]

Yup, looking more and more like it's your coil. Did you try swapping wires around to see if your #2 misfire goes elsewhere and #2 is ok? The P0351 to me indicates a bad coil at #1. Not sure what else it could mean. I think your two codes may either be indirectly related or not at all.

Your meter may not be bad at all. Your plug wires have a range of resistance from 250 to 600 ohms per inch or 3000 to 7200 ohms per foot. With the plug wire resistance so high, that may be why you didn't measure any continuity or ohms. Use the highest setting for ohms, probably giving you 5.0k to 10k-ohms or higher for your wires.

If your coil is cracked, it may start to loose the oil that is used to pack the coils inside. So oil could be present on top, the sides or underneath. True arcing within the coil is not testable as Wiswind pointed out, as there isn't a hard connection like a spark plug has a gap, but electricity can still travel that path, sometimes leaving a visible discolored line like mark on the exterior if that is where is the path of the grounding arc. It would be hard to detect if it is grounding out inside. If the arcing becomes a contact ground, then it is testable by checking for continuity between the metal base of the coil (or another confirmed ground or even the neg. bat post) and each of the plug wire contacts. I tested mine to be sure, the four wire terminals under the wire connector should all also not have continuity to ground. I thought I had mentioned these points previously, but apparently I must have done it on another parallel thread. Anyway, you are testing to see if there is any continuity between any of the contacts to ground. If so, then you have a "shorted out" or "grounded out coil" and it is no good. For $80, I'm testing it to death before I buy a new one that the store won't take back when you try it once. Gone are the $20 or less coils for our newer vehicles.

[wmr95]

Thanks for all the help. I went back out last night and started digging a lil deeper and going over what I had already done. I found the #6 wire at the plug was lose due to my previous T/S. After getting it secure and triple checking myself so as not to come running to the forum for help again on my self induced problem it ran fairly well and no codes. I currently have the 2&6 spark plug wires swapped at the coil. I drove for about 10-15 minutes with 2 stops (van shutoff) and had no probs. I am going to return the wires to there proper location and see what happens. I think at least wires would be a good idea at this point and will probably get those changed asap.
thanks for all the help