1998 V70XC w/Random misfire

Post by **shiloh51933** » 01 May 2016, 14:42

Here's whats going on; I have a misfire on cylinder #5 mostly but if I don't erase the CEL eventually the ECU will record a misfire on cyl #2 and/or cyl #3. I get a code for cylinder #5 then eventually a code for Random misfire and a code for the SAS system. I can't find anything wrong with ignition system, fuel system and vacuum. I have new NGK spark plugs, new wires, new cap/rotor, New MAF sensor, new Cam sensor, New Boost control solenoid, new NGK o2 sensors and I've replaced or resealed all the wiring underneath the hood. The Fuel Pressure is steady at 38psi, she has spark and I can't find any bad hoses or clogged vacuum hoses. Here's what I did find though; I've been having issues with crank case pressure trying to find it's way out through my rear Cam seals which popped off twice since replacing them w/factory rear Cam seals. With that being said I started checking my PCV system to find smoke coming out of my dipstick tube while the motor is running at operating temperature. The PCV system was updated once in the vehicles life but I don't have an exact date on that service, so I'm thinking it needs to be serviced or replaced again. Any thoughts?

Post by **shiloh51933** » 02 May 2016, 06:38

I tried seafoaming intake to no avail, made a good amount of smoke though and I'm sure the Advance Auto commercial store I was at didn't appreciate the Spy Hunter smoke screen!!

Post by **rspi** » 02 May 2016, 06:50

Compression test and check the timing.

Post by **shiloh51933** » 02 May 2016, 07:13

rspi wrote:Compression test and check the timing.

Yeah I was thinking about timing, I guess I can pull cover off, take serp belt off and hand crank to check marks. I do have a compression tester but I leave that for last usually.

Post by **rspi** » 02 May 2016, 07:39

No need to pull the serpentine belt.

Post by **FlyingVolvo** » 02 May 2016, 10:30

What kind of spark plugs? These cars tend to work best with either Volvo genuine plugs or the super cheapo Bosch ones. Avoid any with multiple prongs or iridium/platinum, and make sure they are gapped correctly (.028"). That being said, if it was happening before you put in the new NGKs, they're probably not the issue.

Another thing, may not be related to the misfire issue, but I and others have had issues with non-OEM oxygen sensors, especially in the front. Bosch is the OEM for my 2000 XC, and I imagine it's the same for the earlier years, but someone else may be able to chime in on that.

Sorry that's not much help overall... just trying to throw a few ideas out there.

Post by **erikv11** » 02 May 2016, 11:04

What brand are the cap, rotor and wires? It matters a lot.

And +1 about the separate point: those NGK oxygen sensors could be a problem, for a 98 the dogma is to only go with Bosch there, too.

Post by **kallekula** » 02 May 2016, 11:05

shiloh51933 wrote:I tried seafoaming intake to no avail, made a good amount of smoke though and I'm sure the Advance Auto commercial store I was at didn't appreciate the Spy Hunter smoke screen!!

Post by **shiloh51933** » 03 May 2016, 10:17

erikv11 wrote:What brand are the cap, rotor and wires? It matters a lot.

And +1 about the separate point: those NGK oxygen sensors could be a problem, for a 98 the dogma is to only go with Bosch there, too.

The cap/rotor are Bosch and wires I can't remember off hand but are premium(all of this is less that a year old). I believe the o2's are NTK but could be Bosch, I own many vehicles so I cant remember what has what on every single part...especially the '98 V70XC since I've replaced/repaired quite a bit since buying this car 2 years ago. We also had a '96 850GLT that I did quite a bit of work and obviously buying most of the same parts that I have with the '98 XC. Everything has performed well with all these ignition/emission parts up until now, including the MAF sensor that I replaced in August. I actually exchanged the MAF thinking it would make a difference because it ran a little better unplugged but that wasn't it either.
Here's the only other issues I have found for sure; Evap-I can't fill tank with gas properly as it constantly sets off auto stop on gas pumps, PCV-smoke coming out of dipstick tube. Timing looks good.

Post by **shiloh51933** » 09 May 2016, 11:55

I didn't want to start a new just ask what Volvo calls this valve, it's part of the fuel line to the fuel rail and has vacuum lines from the IM to supply vacuum. I'm still having issues with random misfire at cylinder #5. & #2 or #3 sometimes. It's near firewall on TB side of motor, attached to fuel line into fuel rail.