p0307 (misfire) and the truck sat for a 18 months
#1
04-18-2017, 11:46 PM
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p0307 (misfire) and the truck sat for a 18 months
I bought my 2004 disco 2 with a blown headgasket. The previous owner let it sit for 18 months before deciding it wasn't worth it to him to repair. It has 130k miles on truck.
I pulled the heads and had a local machine shop machined the heads and they did a valve job. I replaced all the gaskets, new plugs, and wires.
I got it running and it seemed to run well for about a day and then it started running rough and got CL p0307 and P0327. I cleared the codes and ran it around town and now it only reads p0307. It had 3/4 of a tank when I got it and last night I filled it up at Costco Premium. I'm guessing that the old gas is causing the misfire and rough running. What are your thoughts? Would a bottle of heet help? Or should I try something else? Thanks, New disco owner
I pulled the heads and had a local machine shop machined the heads and they did a valve job. I replaced all the gaskets, new plugs, and wires.
I got it running and it seemed to run well for about a day and then it started running rough and got CL p0307 and P0327. I cleared the codes and ran it around town and now it only reads p0307. It had 3/4 of a tank when I got it and last night I filled it up at Costco Premium. I'm guessing that the old gas is causing the misfire and rough running. What are your thoughts? Would a bottle of heet help? Or should I try something else? Thanks, New disco owner
#2
04-19-2017, 03:58 AM
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Location: St. Clair County, Michigan
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Imagine you've done the obvious, like checking plug wire and plug. You may have a fuel injector giving you problems, too. Running a tank of gas through it wouldn't hurt, to help eliminate that. I'd add a bottle of fuel injector cleaner to this tank and see if you notice any difference. Anymore, I rarely go super crazy on stuff like this...since the fuel quality is so poor nowadays. Picked up a tank of fuel in my car one day...and you'd have thought I bought water. Anyhow. One of your injectors may be just a little more sensitive (partially plugged) than the others and this is why it is only affecting one cylinder.
Good luck,
Brian.
Good luck,
Brian.
#3
04-19-2017, 07:11 AM
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#4
04-19-2017, 08:21 AM
Winching
I've been doing some research chasing my own misfires. One of the best explanations I've found was this one:
The easiest things to check IMO are the plug condition and compression on the cylinder.
A misfire judgement is based on a lack of acceleration of the crankshaft, via the CKP signal, during the combustion stroke of a particular cylinder.
The ECM uses cam sensor signal, to know what cylinder should have just fired and didn't(there is no such thing as 180 out with the ignition system, as it sparks each cylinder on both compression and exhaust). This means that an issue with the reluctor on the flywheel can cause a misfire fault as well, but would do so with two cylinders at a time. Makes it easy, right?
However, the two cylinders that would be flagged would be two opposite in firing order, 1-6 2-3 4-7 5-8, this is also the set up for the waste spark/coil sharing. A bad coil(as in electrically bad, not physical damage to a HT lead pin) will always cause misfires on two of the cylinders above.
Also, an issue caused by the CKP reading, would effect spark, which is what you would lose for a bad coil too. Luckily, you 'should' get a code for a CKP error, if it is losing its signal.
The ECM uses cam sensor signal, to know what cylinder should have just fired and didn't(there is no such thing as 180 out with the ignition system, as it sparks each cylinder on both compression and exhaust). This means that an issue with the reluctor on the flywheel can cause a misfire fault as well, but would do so with two cylinders at a time. Makes it easy, right?
However, the two cylinders that would be flagged would be two opposite in firing order, 1-6 2-3 4-7 5-8, this is also the set up for the waste spark/coil sharing. A bad coil(as in electrically bad, not physical damage to a HT lead pin) will always cause misfires on two of the cylinders above.
Also, an issue caused by the CKP reading, would effect spark, which is what you would lose for a bad coil too. Luckily, you 'should' get a code for a CKP error, if it is losing its signal.
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04-19-2017, 09:36 AM
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#6
04-19-2017, 05:15 PM
#7
04-19-2017, 06:08 PM
My truck does not run well on Costco premium. I wouldn't use that gas.
Similarly I just dealt with a tank of bad gas from a Chevron station in Coos Bay, Oregon. I've never seen plugs so fouled. I first thought coil pack also because I was seeing codes 306 and 301.
Cleaned the spark plugs and it runs much better now. I also used a can of Seafoam in the tank of bad gas and again in the next half tank of new top tier premium which was before I cleaned the plugs.
No more codes.
Similarly I just dealt with a tank of bad gas from a Chevron station in Coos Bay, Oregon. I've never seen plugs so fouled. I first thought coil pack also because I was seeing codes 306 and 301.
Cleaned the spark plugs and it runs much better now. I also used a can of Seafoam in the tank of bad gas and again in the next half tank of new top tier premium which was before I cleaned the plugs.
No more codes.
Last edited by Dave03S; 04-19-2017 at 06:10 PM.
#9
04-20-2017, 07:27 AM
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#10
04-27-2017, 09:16 AM
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Ok I've run a tank of gas through with B12 chemtool. I verified that plug wire 7 is correct and I pulled the spark plug and it looks good. Each day I have been pulling the codes and the misfire has stopped showing up. However the P0327 knock sensor continues to show up. The disco seems to run fine until it warms up and then I feel it run rough like at a stop light. It seems to run fine on the highway. Tonight I will take a look at the knock sensor for anything obvious. I believe p0327 was to be coming from a maybe a sporadic injector or sometime to cause the p0327 ready and the rough idle. What are your thoughts?