850 Engine Misfiring when hot
#1
850 Engine Misfiring when hot
This 1996 (220KM) car will run fine (perfect)for about ten minutes from cold (I'm talking -5 C)then starts to misfire when warmed up. Difficult to pull away(automatic)from a stop. Sound like its missing on two cylinders. Really chunters. Installed new plugs, wires, cap, rotor, coil,filter. Don't know what to check next. Car will work at speed but I can feel it missing. Gun it and it will go. Doesn't appear to be a fuel problem. Anyone got any idea's or similar experience that led to a solution?
#2
Hi Kwelsh, welcome to the forum.
Does the car have a CEL? If so, what are the codes.
Low fuel pressure can cause missing. When the car is cold the ECU tells it to run rich, that may be why it doesn't miss when cold.
Also, what brand parts did you use to do the tune up? Volvo's really don't like after market parts.
I may also suggest you check your vacuum system. If it's in bad shape, it will cause running issues. How old is the PCV system?
Lastly, you may want to check compression. Low compression can cause problems with smooth running, usually at all temps.
Does the car have a CEL? If so, what are the codes.
Low fuel pressure can cause missing. When the car is cold the ECU tells it to run rich, that may be why it doesn't miss when cold.
Also, what brand parts did you use to do the tune up? Volvo's really don't like after market parts.
I may also suggest you check your vacuum system. If it's in bad shape, it will cause running issues. How old is the PCV system?
Lastly, you may want to check compression. Low compression can cause problems with smooth running, usually at all temps.
#5
#6
The enging light did not come on.
The car was have these problems before I replace all the parts.
There are NO codes. When the enging is running well or when it's missfiring.
On a local mechanic's suggestion I have just put Seafoam in the gas tank. Will let that work it's magic for a few days.
He also recommend sucking Seafoam it into the engine through the vacuum system (going to Utube that).That should clean up a lot of gunk.
Will do the Thottle body cleaning as well.
Haven't got the EGR valve yet.
The car was have these problems before I replace all the parts.
There are NO codes. When the enging is running well or when it's missfiring.
On a local mechanic's suggestion I have just put Seafoam in the gas tank. Will let that work it's magic for a few days.
He also recommend sucking Seafoam it into the engine through the vacuum system (going to Utube that).That should clean up a lot of gunk.
Will do the Thottle body cleaning as well.
Haven't got the EGR valve yet.
#7
Like Gdog said with the EGR, if it's staying open you have a vacuum leak but when cold it's rich enough to make up for it. You might want to check the vacuum lines to see if you have one that's slipped off or cracked.
If you're going to pull the hoses off to get to the throttle body plate to clean it you might also want to pull the Idle Air Control motor and clean that too. It shouldn't be a cause of your present problem but it would prevent it from being one in the future since you're almost there already.
How to:
http://www.matthewsvolvosite.com/for...hp?f=1&t=47533
If you're going to pull the hoses off to get to the throttle body plate to clean it you might also want to pull the Idle Air Control motor and clean that too. It shouldn't be a cause of your present problem but it would prevent it from being one in the future since you're almost there already.
How to:
http://www.matthewsvolvosite.com/for...hp?f=1&t=47533
Last edited by Kiss4aFrog; 01-05-2013 at 01:15 PM.
#8
Thank guys for the help. The Throttle body cleaner and Seafoam has fixed the problem. As the weather here is not that great I am going to wait until the spring to go over it again and follow up on the rest of your advise. I am SURE I am going to be under the hood for some reason!
Last edited by rspi; 01-06-2013 at 07:37 PM.
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