Hello everyone, my 94 940 Turbo Wagon has been developing a problem recently and it finally got much worse yestarday. The car will drive fine if I am light on the gas, but if I quickly give it gas or if I have to accellerate at a normal speed, the car will act like it's running on 2 cylinders, bucking and stumbling and is unable to maintain speed going up a hill. I noticed that the car was running bad yestarday so I turned around and started to head back home, and I have to climb a hill. I made it up going about 8 Mph, and when I reached the top the car backfired and I looked in the rear view mirror and a ton of glowing bright yellow chunks where bouncing around on the road. I quickly pulled over and looked under the car, fearing it was on fire. Nothing was but the catalytic converter was glowing BRIGHT yellow. I popped the hood and the turbo/exhaust manifold was fine, no glow.

What should I be looking for? I am thinking Fuel Pressure Regulator, because the fuel pumps have been getting louder recently and they both work. The tailpipe is really sooty too. It's currently 5 degrees where I live so I haven't looked at it yet, it will be warming up soon so then I will go take a look.

Thanks in advance,
Andrew Woods
94 940T
147,000 Miles

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My Volvo Page

Update:

I felt around the turbo hoses and poked my fingers all around under them to try and find a hole, I coulden't find anything. I tried to start the car and it was hard to start, it took almost a minute to get it going. When it did start it stumbled for a bit and blew black smoke from the exhaust and then it ran fine. I pulled the vacuum hose from the fuel pressure regulator and it smelled like fuel, although it was not wet with it. Ran worse with the AMM disconnected and ran fine with it connected, I brake torqued it in the driveway to build up boost and it did not hesitate at all. I will take it for a drive and warm it up and see if the symtoms come back.

When it was running bad it was only at low RPM's, If I could rev the engine up high, like past 3000 RPM's it would drive like normal, even under full boost. I will update again after I take it for a drive and check things over again.

Thank you for your help.
Andrew Woods

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My Volvo Page

Yeah, there's not much doubt you've smoked your cat; it sounds like the original problem is a leak in the intake plumbing after the turbo.
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Jim McDonald

Andrew - also check the condition of your turbo hoses. The ones on either side of the radiator and the short stocky one to the turbo. They could be torn or have a hole. If they are original, check them very carefully. Often works to run your hand over them (not the one close to the turbo!! HOT) when running. Sounds similar to how my car ran - replaced two turbo hoses and back in business. Good luck!

or a failing cat leading to obstruction....
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Old Volvo's never die..they just get more attention!

sounds like a collapsed cat to me.....

do the procedure in the FAQ...but the glowing and the chunks of stuff says your cat is dead to me...
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Old Volvo's never die..they just get more attention!