2004 Volvo XC90 Misfiring

TATEBE

MEMBER
2004 VOLVO XC90

Engine Mechanical problem
2004 Volvo XC90 Front Wheel Drive Automatic 105, 00 miles

This is a stumper! Only in cold weather the engine misfires until it warms up about 10 mins. I took it to a local mechanic who only works on volvos and he read the codes as misfires in cylinder 4. All coils and spark plugs have been replaced. He even took out all coils and sparks plugs and had them on the engine when he started and witnesses no spark to coil #4 until after a while. He figured it was the ECM. Took it to the volvo dealer and he placed the ECM in the freezer for 30 mins and then back in the car and no misfire. He is not sure what is causing it but recommended a valve job and then they may discover what's wrong. Both are very expensive $2-3,000 and neither is gauranteed to fix the problem. The car runs beautifully in the summer- no misfiring. We live in the southeast so our winters are not that cold. Any thoughts?

4 Replies

RASMATAZ

MECHANIC
75,992 POSTS

Hi tatebe, Welcome to 2carpros and TY for the doantion.

Coils/Plugs are okay-Could be a valve problem on that cylinder-compression/leakdown check will confirm it-or the injector of that cylinder

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Thursday, September 9th, 2010 AT 6:48 PM

TATEBE

MEMBER
2 POSTS

Compression tests were done for each cylinder and all are fine and with in the normal range. If an injector wasn't working then why would the engine run fine in the summer and rough during start up in the winter?

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Friday, September 10th, 2010 AT 1:11 PM

RASMATAZ

MECHANIC
75,992 POSTS

The injector pintle could be sticking due to varnish I wasn't implying that's its defective, you can try checking its solenoid resistances and pressure drop on it-

Check the coolant temperature sensor and also the idle speed controller-Didn' know that engine compression was performed-I gave you that for the no.4 cylinder

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Friday, September 10th, 2010 AT 3:31 PM

JIS001

MECHANIC
3,408 POSTS

The first thing you may want to do is have the ECM software updated if one is available. After that if you still have issues with that cylinder misfiring, swapp out injector #4 with say #2 and see if the mifire follows. If it does the injector is bad. If it is the same cylinder have them do a cylinder leakage test. You could be having a valve sticking.

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Saturday, September 11th, 2010 AT 1:13 AM