P0307 Cylinder #7 Misfire Detected

Posted by: BritVicManUk

P0307 Cylinder #7 Misfire Detected - 10/01/06 09:10 PM

hello folks
well after a quick trip to advanced "oh no" parts in appleton the OBDII pulled P0307 cylinder 7 misfire detected
and i checked the plug which had carbon deposits on it(new set of plugs on 2 weeks ago) and the resistance in the injector is 15.9 ohms and haynes said that 13.5 to 19.0 is ok..still got that awful judder/shudder and 100% know that its that bloody cylinder #7..any tips before i march to the mechanic with my tail between my legs
cheers ian
Posted by: Modly

Re: P0307 Cylinder #7 Misfire Detected - 10/01/06 09:22 PM

I had two problems with my #7 that caused it to misfire when I first had it.

My injector clip wasn't secured to the injector (Which I'm sure you've taken care of after testing impedence), and my spark plug boot had a small hole in it, and shorted out in the head, so it never got the spark to the plug.

Test out your wires, or swap two of them around, and see if it pulls a new code. *edit* Scratch that last part, I forgot that some of them use COPs, so it could be a faulty COP instead. Test it for spark with somebody else, and see if it will arc out on a metal surface. Test the boot out as well, and see if it is damaged.
Posted by: bamf70

Re: P0307 Cylinder #7 Misfire Detected - 10/01/06 09:25 PM

Quote:

hello folks
well after a quick trip to advanced "oh no" parts in appleton the OBDII pulled P0307 cylinder 7 misfire detected
and i checked the plug which had carbon deposits on it(new set of plugs on 2 weeks ago) and the resistance in the injector is 15.9 ohms and haynes said that 13.5 to 19.0 is ok..still got that awful judder/shudder and 100% know that its that bloody cylinder #7..any tips before i march to the mechanic with my tail between my legs
cheers ian



I suggest you swap the COP off #7 and any other cylinder. Pull the - terminal on the battery for about 20 minutes then replace it (clears any codes in the ECM). Then start it up and when the CEL comes back on see if it the misfire follows the COP. If it does, just get a new COP and problem solved.
Posted by: BritVicManUk

Re: P0307 Cylinder #7 Misfire Detected - 10/01/06 09:38 PM

ooops sorry lads but its the 95 vic which had the 2 coil packs so i guess the cop thingy is out of the question i guess and the plug wires where replaced 2 weeks ago when the problem started so other help maybe needed here
Posted by: bamf70

Re: P0307 Cylinder #7 Misfire Detected - 10/01/06 09:40 PM

Quote:

ooops sorry lads but its the 95 vic which had the 2 coil packs so i guess the cop thingy is out of the question i guess and the plug wires where replaced 2 weeks ago when the problem started so other help maybe needed here


The idea is the same here. Swap the coil packs around if the misfire comes up again on plug #7 then the packs are good but if it jumps to a different cylinder than it's the coil pack.
Posted by: Modly

Re: P0307 Cylinder #7 Misfire Detected - 10/01/06 09:40 PM

See if the coil end of the plug wires are all properly seated. They may not be connecting properly.
Posted by: Warren'74

Re: P0307 Cylinder #7 Misfire Detected - 10/01/06 09:45 PM

Re check the wires for proper resistance first. Replace plug, just because.

If that fails to solve it, do a compression test. Could be a broken valve spring.
Posted by: Not_Gramps_Marq

Re: P0307 Cylinder #7 Misfire Detected - 10/01/06 10:38 PM

BritVicManUK - I just sent you a PM. I have the whole top end from a 95 so if you want to plan a day to come down we can go through it. I have lots of parts. look forward to hearing from you.
Posted by: BritVicManUk

Re: P0307 Cylinder #7 Misfire Detected - 10/01/06 11:13 PM

heh got yer PM and PM`d you back so lookng forward to it will get more details middle of week. heh warren i hope its not a valve spring as thats a pain in the arse aint it? aint got valve spring compressor
Posted by: Not_Gramps_Marq

Re: P0307 Cylinder #7 Misfire Detected - 10/01/06 11:26 PM

If it was a valve spring you'd more than likely have some noise. Here is what a broken Valve spring does:





you could have lost a cam follower. Which has been known to happen. Not too hard to fix though
Posted by: BritVicManUk

Re: P0307 Cylinder #7 Misfire Detected - 10/03/06 07:43 PM

heh mate
i pM`d you so go take a look and fingers crossed