Volvo 480-Rough running

[CTCNetwork]

Hi,

Most plugs are pre-gapped these days, particularly multipoint ones..
Gapped to 0.8 probably which maybe a fraction wider than factory recommendation..
But that, in itself, would not cause such bad running...

Des. . .

[Paul240480]

I'm with hoff! Rocker gasket leaks, I think are due to blockage in the crankcase ventilation (PCV?). Once these do completely block, it forces a build up of pressure and eventually the oil has to come out somewhere- usually through the rocker cover & down onto the plugs. Had it on my 240 & simply changed the gasket the first time, surprise surprise it leaked again in about 500miles LOL!
Keep thinking about checking my 480, but I'm always reluctant to fiddle too much for fear of ballsing it up
Anyway good luck.

[matt_tily]

Sorry just was wondering what the crankcase ventilation is is it the tubing off.Anyone have any more ideas on the rough running problem I'm really confused tried almost everything I can think of.Only other things are a manifold leak or a cat blockage I think.the cat does look really rust and like its seen better days can this cause rough running?

Thanks for everyones input on this really want to get it sorted now.

Cheers,

Matt.

[Paul240480]

Hi PCV = positive crankcase ventilation.
Hopefuly you can read the attachment I have uploaded and hopefully it is relevant!

The only other thought is an air leak, not sure if someone else has mentioned this.......... but, with the engine running try spraying something like carb' cleaner or wd40 on the fuel injectors 1 by 1. If you have a leak the spay will seal it for a few seconds causing the engine to run perfectly for a few seconds. If this works replace the injector seals.
Also try a spray around the inlet manifold as the gasket here can leak allowing air in which will cause erratic running / tick over probs.

Kind regards

[matt_tily]

Hi think the hoff and paul clark were right looks like it may be dripping from the front right hand side of the rocker cover.Paul thanks for your diagram.But need a pic of the valve and hoses to clean re the pcv (positive crankcase ventilation) or a description asap if possible because I am planning on giving it a good clean out this evening before it gets dark.Is it a cylinder thing with black insulation material around woth one piece of tubing going to the throttle body (accelerator cable assembly), because took that off and its full of gunge.

Thanks reply soon if possible.

Thanks hoff and paul clark for your help, its been very helpful and is appreciated alot and anyone else who has input ideas.

Matt

[matt_tily]

one more thing if the cylinder thing with insulation round it is the pcv valve how do you remove it to clean it?

Cheers lads,

Matt

[Paul240480]

Hi Matt.
Yours is the 2.0Ltr & mine is 1.7 Turbo, so I am not exactly sure if positioning is the same.
Anyway, I think I'm right in saying that there will be a thin (ish) pipe coming from the inlet mainfold. This should lead back to all parts of the crankcase ventilation system. Take the pipes off one by one a clear them of any gunk. If you cannot clear them then replace. Also if the hole into the manifold is blocked clear that as well.
Hope this helps, if not I'm sure someone else will 'pipe up' & be more specific than I am. I'm still learning BIGTIME myself LOL!

[matt_tily]

I'm probably being a muppet but I cant see the positive crankcase ventilation (pcv) system ie hoses and valve.Can someone send me a pic or give me a more detailed desccription of where it is.Is it on the front of inlet manifold by plugs or at the rear by fuel rail coolant temperature sensor etc

Thanks in advance need help asap if possible and thanks paul for all your help.

Matt.