Hi all. I need some diagnostic insight.

The fuel pressure regulator on the injector rail failed on my wife's '94 850 (not a turbo). Fuel was squirting out the pressure regulator's vacuum line. I think that therefore at least some gas got into the cylinders and possibly into the oil. I replaced the fuel pressure regulator. Starting the car took a while. When it finally did catch, it ran very poorly on only a couple of cylinders, smoked a lot, had a nasty metallic knock which seemed to come from the top of the engine on the intake side. I ran it for about a minute but it didn't smooth out much. Turned the engine off, checked all electrical and vacuum connectors, which were all OK. Said some bad words and knocked off for the night.

Next day I changed the oil and filter (oil level was OK, oil didn't smell much like gas), pulled out the plugs (some carbon but not bad, also not oily), looked throug plug sockets into cylinders (no obvious holes in pistons), topped off the coolant which was a quart low (probably not related, but maybe all the details will help), restarted the car. Ran much better but still had a bad (though better) metallic knock. Turned the engine off and said some more bad words.

Called DJ, a buddy and certified Volvo technician. He listened to the engine, looked dour (honest!), advised me to check the timing belt and hope it had jumped only a single tooth. I checked: timing is dead on per Bay 13 procedure (Hey Bay 13: Thanks!). He said the worst case was that I might need a rebuilt head at about $1800. Ouch.

The knock sounds to me just slightly worse than the valve noise when the engine was 3 quarts low on oil (oil pressure light had failed on instrument cluster. Yes, I know that's a lousy excuse. Wife doesn't like checking her oil level and I rarely drive her car...). However, that noise vanished when I topped up the oil. This noise didn't vanish when the oil level is right.

Anybody have suggestions of what to check next? Thanks for the help.

-- Bruce

(I understand the 4-cylinder rear wheel drive Volvos. I sure as heck don't understand this silly transverse-engine front wheel drive 850...)
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-- Bruce / '82 244 (315k miles!), '86 745, '87 760Ti, '94 854