PDA

View Full Version : Misfire - 2003 S60R manual



jacks60r
Saturday 6th April 2013, 14:42
Hi guys,
just wondering if anyone can help.
I've recently acquired what seems to be a lovely misfire.
The cars seems to run perfectly well in every way possible, ides fine, drives fine etc, unless under full boost. It almost sounds as if traction control has interfered, although no DSTC light flashing on the dash. AWD is definately still working, so it's not just a simple case of wheel spin etc.
I have had it hooked up to the laptop to no avail, no codes stored out of the ordinary, just a code that was set by having no cat.
I suppose a bit of background on the car would help;
It's on an 03 place with 127k on the clock.
It has been remapped for the last 50 to 60k, and also has a 2.5 stainless exhaust with a decat.
I did recently replace a coil on cylinder 2, and that fixed a different misfire, although this on sounds completely different.
I have bought another new coil, and checked resistances of all coils, and compared then to the brand new one, and all were found to be very similar.
My next step is to swap it from cylinder to cylinder, and take it for a test drive until it either fixes the problem, or all coils on all cylinders have been eliminated.
Any help or ideas of where to look and what to look for would be appreciated.
Jack

stribo
Saturday 6th April 2013, 14:54
Have you tried changing the spark plugs?

oblark
Saturday 6th April 2013, 15:13
Have you tried changing the spark plugs?

What he said :)

Plus if a coil pack was playing up wouldn`t that show up as a fault ?

jacks60r
Saturday 6th April 2013, 16:03
Spark plugs are only about 3000 miles old, and all gapped correctly.
Jack

Santa
Saturday 6th April 2013, 18:18
Does it happen at a certain rpm range?

Squirtydog
Saturday 6th April 2013, 18:26
When coil packs went on mine it showed as a fault code plus it was far more noticeable than what Jack is describing. Car was undriveable.

jacks60r
Saturday 6th April 2013, 20:19
Usually happens at around 2500rpm (but that's when peak boost is coming in) and finishes around 3500-4000, but it seems as though the ECU is cutting boost back. It seems as though the misfire stops because boost is lowered, rather than stops because of higher revs. I would think that if the ECU would hold boost at higher rpm, then it would still misfire at higher rpm, if that makes sense?

Harvey
Saturday 6th April 2013, 20:27
Has the fuel filter been changed.
Could be fuel pressure sensor but that would show up with a code.

Here is a older thread might be of interest

http://www.vpcuk.org/forums/showthread.php?46561-R-owners

Santa
Saturday 6th April 2013, 20:32
Usually happens at around 2500rpm (but that's when peak boost is coming in) and finishes around 3500-4000, but it seems as though the ECU is cutting boost back. It seems as though the misfire stops because boost is lowered, rather than stops because of higher revs. I would think that if the ECU would hold boost at higher rpm, then it would still misfire at higher rpm, if that makes sense?

Sort of. Wondering if its fuel cut because turbo boost pressure was to high. Does it happen under partial throttle?

jacks60r
Monday 8th April 2013, 09:49
I moved the new coil along to the next cylinder, and put the old Volvo plugs in, and it appears to have sorted the misfire! Thanks guys

JamesT5
Monday 8th April 2013, 14:02
Try changing your fuel filter, also it may have something to do with the remap.