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speedysmartypants

misfiring vr6

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my vr6 is missing. plug in cylinder 6 keeps getting covered in oil. had the head reconditioned at stealth in febuary and they said they changed the valve seals and compression tested it for me. is this mabye a dodgy injecter? also my exhaust is blowing before and after the cat, will this add to the misfire. thanks for any advice

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Exhaust blowing after the cat should be ok, but it won't help. Oil on plug 6 is classic VR bore wear scenario, unfortunately.

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Oil on plug 6 is classic VR bore wear scenario, unfortunately.

 

Yup - do a dry compression test followed by a wet compression test and compare to confirm. If the wet reading is significantly higher then the oil is coming from the rings/bores. If the wet reading is the same then the oil is coming from the head or gasket.

 

Is it definately oil and not petrol?

 

If its petrol on the plug it may be an electrical problem (check for a spark on that plug) or it could be an injector (I had this recently) pull it and swap for a known good one or test it by spraying into a measuring jug.

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changed injectors and no difference. did a compression test last night and results are as folows

1)168 2)180 3)160 4)180 5)120 6)175. done the test twice and got same results. did a wet test on no.5 and got 145. gunna do a leak test when i get sum hose. any thoughts?

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5 looks low. Could be a lot of things .. was the engine up to temp when you tested it? It needs to be.

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yep was hot. gunna get a cylinder leak tester this week now. i know it could be the valves but stealth did a full head recon. it wasnt right before it went there and it wasnt right after. i asked them to check compression when it had the recon and they said it was fine. they said it wasnt running right cos the ecu needed to re-learn the car and i needed new ht leads. bought another set of magnacor leads and no difference. so could be the pistons or bore or stealth did sumthing wrong maybe. theres loads of reasons they could give to say its happend since so i wont be able to prove its their fault if it is. anyways i hope not cos they have a good reputation and vince is a nice guy. if its the rings, bore of watever im going to oversize with sum 83.5mm pistons. should be fun

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How much is a re-ring on a VR6? I'd guess it's a fair amount of labour, given that you have to drop the crank out..

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