Hi, I have been searching around and trying to figure out what I have going on. I am mechanically inclined but this one is stumping me.

I have a 98 V90 with 195K miles. I started to get P0300, P0302, P0304, P0305 codes. I replaced the plugs with factory Volvo plugs and no change. I found the coil packs all had cracks running down them so I replaced those with generic replacements and again no change. The P0422 has been mixed in there also and I know that can be caused by the random misfires.

 

Ran a compression test. All cylinders are between 210 and 220. No burnt valves Or blown head gasket.

Plugs are look good but do have some carbon on them. I could see some buildup on the tops of the pistons. Thinking this might be coming from the fuel system.

 

How old is the fuel filter? I would check fuel pressure. P422 is a cat issue, may be starting to clog.

 

Yeah, I am thinking that the fuel filter is the next move. I don't know when it was done last. I am sure that the p0422 is coming form the misfire based off of the last smog printout. What PSI do the fuel system in these things run at?

 

Somewhere between 35 and 45 psi.

 

Just wanted to add some clarity on the fuel pressure spec for the car.

"The Volvo green manual states that the Regina system fuel pressure should be 43.5 +/- 1.5 psi static pressure. The rail pressure should be 43.5 minus the vacuum tester vacuum at the regulator vacuum port. This tells if the regulator is working. "

 

Went and tested the fuel pressure. Was 43 with the vacuum to the FPR disconnected. With it hooked up at idle it is 36.5 so we are good there. I am still going to replace the filter because I do not now when (if) it was done.

The odd thing that I figured out is that it only acts up right after filling the tank. I only run the pump until it clicks off. If I go about 10-15miles and shut it off and let it cool it is fine until the next fill up. I am thinking that the evap purge valve might be sticking after doing some searches for other people having the same issue.

 

Sounds correct.

 

I would tend to concur. With that many cylinders misfiring, I would not expect an ignition issue but fuel supply. Keep in mind that the computer sees a misfire as the crank slowing down on the firing of that cylinder. It does not literally see no spark in the plug.

The other issue that you may have is a pretty substantial air leak that leans out the cylinder. I once chased a misfire on a 94 model 960 only to discover that the intake gasket was breached on one cylinder. After that, it ran fine.

 

I have checked pretty hard for air leaks and can not find any. It is also weird that it only acts up right after the tank is filled. I am leaking towards an EVAP issue at this point. Should pin down to canister or purge valve from what I can find.

 

Sounds like the purge valve is stuck.

 

OK, Now to figure out where they put the thing. All of the diagrams and info I can find only shows for the s70.

 

SMH, I think I might have fixed it and found the issue..................... The hose from the intake to the purge was so soft that it was collapsed at idle. I replaced the hose and purge valve.

Lets see if it is all better now.

 

Fixed?

 

It is running a lot better and did not run bad after filling it up like it had been. I am thinking the hose was that issue. Something is still not quite right and the p0422 code popped up when the wife was driving it home from work today. Thinking there is probably another hose that leaking and causing issues. I also have a coolant leak that I need to hunt down from the back of the block. I think it is the pipe that the heater hose goes on at the head. Always something with this thing.