2001 Vanden Plas
#1
2001 Vanden Plas cylinder misfire. I'm stumped
Finally, it's back together. I started it up yesterday and it ran great, check for coolant leaks and there was 1 that I have since fixed. I go to start it up today and I have a rough idle and cylinder 6 is misfiring. Also said misfire rate exceeds emission. Some background info. Both heads rebuilt. Timing chain both primary and secondary replaced. New spark plugs. Battery fully charged. I'm stumped on this one. Could it be a fuel problem?
Last edited by jagdohrman; 07-29-2017 at 02:48 PM. Reason: Title
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#9
If the misfire is moving when changing the coils, then it's likely having a faulty coil.
What Bob wants to point out is that you should double check your cylinder numbering. Your OBD interpretion of p0306 is following the ISO standard for cylinder numbering. But Jaguar didn't use the ISO standard for their cylinder numbering (at least not back then for the AJ26/27 engine layouts).
Here's what I'd suggest to be double check:
- get the proper DTC catalogue for your car and model year (e.g. from jagrepair.com)
- read the codes and ignore your reader's description behind p030X
- look up the meaning of the code in the before mentioned DTC catalogue and use the cylinder layout Bob has provided to identify the right cylinder
Cheers, Alexander
What Bob wants to point out is that you should double check your cylinder numbering. Your OBD interpretion of p0306 is following the ISO standard for cylinder numbering. But Jaguar didn't use the ISO standard for their cylinder numbering (at least not back then for the AJ26/27 engine layouts).
Here's what I'd suggest to be double check:
- get the proper DTC catalogue for your car and model year (e.g. from jagrepair.com)
- read the codes and ignore your reader's description behind p030X
- look up the meaning of the code in the before mentioned DTC catalogue and use the cylinder layout Bob has provided to identify the right cylinder
Cheers, Alexander
Last edited by xjr2014_de; 07-30-2017 at 03:34 PM. Reason: typo
#10
I looked it up, it is cylinder b3(7). It says possibly causes are from code p0300 but I didn't have that. It means random misfire. I'd like to add that it started fine after I had everything together. I put water in the coolant system to flush out any contaminates and to find any leaks. There was a leak right up by the throttle body and water sprayed all over eventually. I didn't think anything of it and that's when I started it the next morning and found these codes.
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Yes, the coil harness. The coil covers have a thin gasket that leaks with age. I would remove all the coils from that side, but leave them connected to the harness. Then get any water out of the plug wells and coil boots before re assembly.
A little grease on the cover gaskets will help in keeping moisture away from the coils and plugs.
A little grease on the cover gaskets will help in keeping moisture away from the coils and plugs.
#14
Yes, the coil harness. The coil covers have a thin gasket that leaks with age. I would remove all the coils from that side, but leave them connected to the harness. Then get any water out of the plug wells and coil boots before re assembly.
A little grease on the cover gaskets will help in keeping moisture away from the coils and plugs.
A little grease on the cover gaskets will help in keeping moisture away from the coils and plugs.
#15
It's possible that it evaporated since then (because of warm engine) leaving corrosion behind causing intermittent failures. So do yourself a favor and check all coils, coil boots (in particular the contact springs inside) and spark plug terminals for corrosion, clean the contacts, treat them with contact grease/spray and you're safe. If you want to do it thouroughly, get the spark plugs out and check the threads and the collar+washer for any signs of extended corrosion/contamination. As the metal case/shell acts as a ground for the spark plug, major contamination (esp. at the collar and the washer) will result in a poor ground connection.
#16
It's possible that it evaporated since then (because of warm engine) leaving corrosion behind causing intermittent failures. So do yourself a favor and check all coils, coil boots (in particular the contact springs inside) and spark plug terminals for corrosion, clean the contacts, treat them with contact grease/spray and you're safe. If you want to do it thouroughly, get the spark plugs out and check the threads and the collar+washer for any signs of extended corrosion/contamination. As the metal case/shell acts as a ground for the spark plug, major contamination (esp. at the collar and the washer) will result in a poor ground connection.
#17
I did read that, but my statement aimed at any coolant residue/other contamination which might have been build up between the spark plugs and the head. Maybe there's some contamination left from before the head rebuild? Or had been the whole head sandblasted/thoroughly cleaned incl. the spark plug wells? ;-)
#18
I did read that, but my statement aimed at any coolant residue/other contamination which might have been build up between the spark plugs and the head. Maybe there's some contamination left from before the head rebuild? Or had been the whole head sandblasted/thoroughly cleaned incl. the spark plug wells? ;-)
#19
Based on that it's quite unlikely...but for peace of mind no big deal to check the plugs, coils and wells...
So I was re-reading the story above and you posted that you initially got a misfire on cylinder 6, means Code P0306, right?
The Jaguar documentation says for p0306 it's cylinder 6 = B2 = 2B. 2B is located on bank B = the drivers side (LHD).
A few posts later, you state that you now have a misfire on cylinder 7 = B3 = 3B. Which code do you obtain? P0307?
If yes, you might be on the wrong track, since cylinder B3=7 and cylinder B2=6 are on the same side!!!! It's not the passenger side! That's what Bob and I pointed out a few posts earlier. Check the attachment for clarification concerning the "historical" cylinder numbering for the V8 Jags before MY 2004.
So I was re-reading the story above and you posted that you initially got a misfire on cylinder 6, means Code P0306, right?
The Jaguar documentation says for p0306 it's cylinder 6 = B2 = 2B. 2B is located on bank B = the drivers side (LHD).
A few posts later, you state that you now have a misfire on cylinder 7 = B3 = 3B. Which code do you obtain? P0307?
If yes, you might be on the wrong track, since cylinder B3=7 and cylinder B2=6 are on the same side!!!! It's not the passenger side! That's what Bob and I pointed out a few posts earlier. Check the attachment for clarification concerning the "historical" cylinder numbering for the V8 Jags before MY 2004.
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jagdohrman (07-31-2017)
#20
Based on that it's quite unlikely...but for peace of mind no big deal to check the plugs, coils and wells...
So I was re-reading the story above and you posted that you initially got a misfire on cylinder 6, means Code P0306, right?
The Jaguar documentation says for p0306 it's cylinder 6 = B2 = 2B. 2B is located on bank B = the drivers side (LHD).
A few posts later, you state that you now have a misfire on cylinder 7 = B3 = 3B. Which code do you obtain? P0307?
If yes, you might be on the wrong track, since cylinder B3=7 and cylinder B2=6 are on the same side!!!! It's not the passenger side! That's what Bob and I pointed out a few posts earlier. Check the attachment for clarification concerning the "historical" cylinder numbering for the V8 Jags before MY 2004.
So I was re-reading the story above and you posted that you initially got a misfire on cylinder 6, means Code P0306, right?
The Jaguar documentation says for p0306 it's cylinder 6 = B2 = 2B. 2B is located on bank B = the drivers side (LHD).
A few posts later, you state that you now have a misfire on cylinder 7 = B3 = 3B. Which code do you obtain? P0307?
If yes, you might be on the wrong track, since cylinder B3=7 and cylinder B2=6 are on the same side!!!! It's not the passenger side! That's what Bob and I pointed out a few posts earlier. Check the attachment for clarification concerning the "historical" cylinder numbering for the V8 Jags before MY 2004.