2002 S80 Misfire 2.9l non turbo

Bigmaxy · Post by **Bigmaxy** » 15 Feb 2011, 19:20

Hi All

I have a 2002 S80 2.9 non turbo that has an intermittent misfire at idle. Sometimes it will run fine and other times it will misfire at idle every time. It will run perfectly once throttle is applied. No misfire or hesitation.

It is showing the following two codes
P0300 Random/Multiple Cylinder Misfire Detected
P0016 Crankshaft Position - Camshaft Position Correlation (Bank 1, Sensor A)

When the problem is being experienced the idle will jump around between 500-900 and the dash lights will dim, after leaving it like this for awhile the check engine light may begin to flash and throw the code. But not always. Sometimes the car will go for weeks without any problem, full power and economy. This leads me to think it is not a timing belt problem.

The history.
Had a high pitched whine and emission related code (can't recall which, o2 sensor)
Car went in to have water pump, timing belt and tensioner's replaced.
Found that large amount of crank case pressure due to oil catch tank being blocked was causing whine (removed oil cap or dipstick to find this one out). The catch tank was replaced.
After timing belt work was done the car started with the intermittent misfire.
Found that mechanic who did the work did not install tensioner properly and there was excessive tension on the belt, this was done again and the tensioner is now showing the correct position. I've checked the timing marks on the cams and the are aligned correctly, can't find the mark on the crank pulley so can't check if cams are in the correct position related to crank. However are problem is intermittent I am guessing they are correct.

After the catch tank was replaced and in an effort to diagnose the idle problem, I cleaned the throttle body and the VCT intake solenoid (VVT hub reset valve). neither of which helped. ETM is the Bosch part)
I then used Subaru Upper Cylinder Head cleaner (similar to seafoam from what I understand) and this fixed the problem for quite a period of time (maybe 2 months).
The problem has now come back. I tried another clean with the upper cylinder cleaner but no luck this time, possibly a coincidence.

So right now...
I would like some advice from people that might be able to point me in the right direction.
CVVT Solenoid (hub reset valve) - should I replace as cleaning might not be sufficient

Was also thinking of a possible bad ignition coil pack.

All help would be much appreciated. Hope I have provided enough info here and not too much to make it overwhelming.

Cheers.

Post by **jimmy57** » 15 Feb 2011, 21:01

that car has injectors with 12 tiny holes for spraying fuel. If one gets clogged partially it will cause the fuel trim regulation lots of problems. The leaned cylinder will cause oxygen sensor to register the extra oxygen and the ECM will add fuel to that bank (actually that group of three cylinders 1-2-3 or 4-5-6) until the reduced oxygen from the two rich ones masks the lean condition extra oxygen cylinder. The fuel trim will oscillate and at times it will lean misfire. Often the ECM will set a faulty catalyst code with the misfire codes.
Removing fuel rail with injectors and looking at tips of injectors usually will reveal the problem as the trouble maker will have dirty tip and the others will be clean.

CVVT problems will set codes readily, probably not that. Rough running from wrong cam positioning is a definite code setting problem.

Bigmaxy · Post by **Bigmaxy** » 17 Feb 2011, 00:23

Thanks Jimmy.

May take me a few days to get around to pulling the top part of the intake manifold off to get to the injector rail. In the meantime I pulled the plugs to check for any differences in color to see if I would notice any cylinder running leaner than the others. Can't say any were obviously worse than the others.

btw. Other things that I have tried while diagnosing this problem, running injector cleaner through many tanks of fuel and replacing the fuel filter. Also brand new Volvo spark plugs.

I will see how it goes for the next few days and pull the fuel rail and injectors to check.

Cheers

Bigmaxy · Post by **Bigmaxy** » 23 Feb 2011, 02:52

Finally got around to pulling the injector rail out and have taken some before pictures. Cyl2 looks a bit suspect but not sure if it would be bad enough to cause problems, any opinions??? While they are out I will see about getting them cleaned.

Cylinder 1

Cylinder 2

Cylinder 3

Cylinder 4

Cylinder 5

Cylinder 6

Bigmaxy · Post by **Bigmaxy** » 27 Feb 2011, 21:01

Put the injectors and rail back in (o-rings were a bit of a pain in the backside to source, the place that cleaned my injectors gave me some green bosch ones which seemed to fit in ok and are not leaking any fuel, they couldn't flow test the injectors though and used an ultrasonic bath)

Car now seems to surge on constant throttle. Upon start up the car would go to a high idle (1200 rpm?) and quickly drop down to 700 or so. Now the idle stays quite high and will drop to 1000 or so, but will rise and fall. When driving at a constant throttle opening you can feel the car surging a bit. After driving it will idle at around 700 again.
due to intermittent nature of previous problem (misfire) I am not yet confident it has been resolved but I do know that another problem has now been added

Any ideas?, feel like I am talking to myself here. Going to check for vacuum leaks tonight if I get the chance.

Post by **jimmy57** » 27 Feb 2011, 22:38

OK, first off, Aussie version uses the 4 holers that Volvo used in 2.9 non-turbos for 1999 qnd 2000.
Never can guess what pieces vary with sales market.
The fuse for engine management under hood is marked either ECM or Engine Management. Remove it with key off and leave it out for a couple of hours. Before you worry too much more try to let the fuel trim memory and idle control memory go back to default and start their adjustments over. It will need to warm up and idle for a few minutes and then drive it at a steady speed a couple of miles and see if that improves or fixes it. IF not then re-read fault codes from ECM and see what is stored. The p0016 may be the culprit and that would be for intake CVVT control issues. I have not seen CVVT cause misfires

Bigmaxy · Post by **Bigmaxy** » 27 Feb 2011, 22:53

Thanks again Jimmy.

Have just pulled #6 ECM/MAF/Injectors
Have not touched any of the others incl #23 ECM/E.M.Rel Coil

edit...3hrs later...
Good news and bad news.

Good news - Reset of fuel trim seems to have resolved surging issue. Thanks for the advice
Bad news - Misfire/Rough idle is still there. No check engine light yet. Will have to check for pending codes.

Bigmaxy · Post by **Bigmaxy** » 28 Feb 2011, 22:02

Next day..problems persist.

I have uploaded a 5mb video to demonstrate the problem. While the idle appears to be stable looking at the tach you should be able to hear the rough idle and see the shaking (that is the car, not the unsteady camera operator, lol) You will also notice the dash lights dimming in time to the rough idle.
A few secs after I stopped recording the check engine light began to flash. The OBDII was showing a pending code of P0300 Random cylinder misfire.

Hope some of you folk may have some ideas.
S80 Misfire

Post by **boosted5cyl** » 01 Mar 2011, 09:13

Listening to that Im sticking with my VVT diagnosis. That how mine sounded when the timing was off. Having the marks line up is only one part of setting the timing correctly. Look at this this way:

Car was idling fine
Timing belt was replaced by mechanic
Mechanic didnt set tension correctly, indicating either a bad day or lack of knowledge
Car now does not idle smoothly following work peformed

Until you can verify its set correctly you may be chasing your own tail

One thing to can do to check the coils at idle is disconnect the power to the injectors and see if it makes any difference to the running of the engine. So for example, pull the injector power connector for cyl#1, if the running of the motor changes, then that cylinder is likely working ok. Replace the connector and then move to #2 and so on all the way to #6. If you find that you disconnect an injector and it makes no difference to the running, swap the coil on that cylinder with one that appears to be OK. If the issue moves, then thats the offending coil.

Bigmaxy · Post by **Bigmaxy** » 03 Mar 2011, 01:41

Yep VVT was something I was def suspecting.

Today I tried unplugging the coils 1 at a time again and couldn't detect much difference. It was getting to a point where I was starting to imagine differences I think.

I decided to unplug the VVT solenoid and immediately the idle went back to normal, it raised slightly however before settling down. I plugged the solenoid back in and the idle stayed fine.
Went for a drive and after awhile the misfire came back, upon disconnecting the solenoid again the idle went straight back to normal.
Seems to be a fairly conclusive conclusion that the problem is related to the VVT solenoid, unless it is something obscure.
I would have expected unplugging the solenoid to have made no difference rather than improve the idle.
My theory would have been.
unplugged = no voltage to the solenoid = solenoid position to suit idle
hence
as rpm increases = solenoid position moves with increased voltage to suit the higher rpm
as idle returns the voltage at solenoid should reduce to nil. giving the same result as unplugging.

Sooo. Do we think it is the solenoid or the vehicle wiring?