2004 v70 misfire cylinder 2

Ryanxr400 · Post by **Ryanxr400** » 03 Nov 2014, 20:58

Hi guys, I have been a lurker for sometime now… And tonight I took the plunge and created an account.
My problem is on a 2004 v70 2.5 turbo. Great car, well cared for, and clean. 120k miles. Recently it has developed a ever so slight misfire that trips the check engine light. The difficulty is that it only happens when the car is cold. It is hardly audible and can really only be heard at the tail pipe with a slight "putt putt" sound that's barely out of rhythm . Once warmed up it runs perfectly with no hesitation and no hint of a misfire whatsoever. No loss of power, perfect sound, Etc.
I am a decent mechanic and handle most issues myself. Things I have done so far in chasing this issue is I stared with replacing the plugs with authentic volvo it's. This help the issue and definitely smoothed the car out as the plugs needed to be done, but to no avail. The misfire continued. Next, I replaced all the coil packs. Again this smoothed everything out and helped a ton but the misfire continue the next day. I searched for a vacuum leak, but found none. I figured it was on schedule to have the PCV system checked so I replaced it with a full kit from IPD. I found a fair amount of cunk in the bottom port of the oil box, I cleaned it all out and the car sounds like it breaths better (probably in my head) ... But still the cel came back on. Misfire cylinder 2!!
My question is this, before I dig in and start looking at the head and the valves, is there a possibility that there is a computer or ignition system that needs to be reprogrammed (flashed?) and updated? It's a long shot I know. I looked for pinch the wires and I found none.
This misfire is starting to give me a headache! Thanks everyone.

Post by **oragex** » 04 Nov 2014, 06:09

Another relatively easy & inexpensive check is to remove and flow test the injector in cyl #2. Other than that, maybe it has a small head gasket leak or an issue with the valves.

draser · Post by **draser** » 04 Nov 2014, 08:04

After all that maintenance you did it really sonds like it's a cyl 2 problem - I'd read the spark plugs, especially if you still have old ones, to see if #2 looks different. If it's smoked it's too much gas, white deposits it's coolant, etc.

jamuleis · Post by **jamuleis** » 04 Nov 2014, 11:43

my bluetooth obd reader showed same fault. turned out spark plugs where realy bad specialy 2nd cilinder

richard baumann · Post by **richard baumann** » 04 Nov 2014, 12:12

I chased a misfire on cyl #2 in my 2004 R for 35,000 km, did the plugs, did the coil packs. I finally took it to a local independent Volvo shop that had the correct software to see that the misfire was only there on a COLD start up and that the #2 injector was holding open when cold and flooding the cylinder. There was a short puff puff noise from the exhaust when cold.

I got a set of injectors from IPD and all has be fine for the last 50,000 km.

Ryanxr400 · Post by **Ryanxr400** » 04 Nov 2014, 12:28

That is very interesting Richard! I will look through that angle and report back to what I find! Thanks