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Volvo acceleration problem

I drive a 1985 Volvo, 760, turbo…4 cylinder (wagon). The car does not accelerate very well. At any speed, if you “floor” the gas pedal, the engine responds as if it is not getting enough fuel. If you open the hood, grab the throttle mech, and rev the engine, there seems to be NO acceleration problem. I’ve had the turbo off the car and inspected. One mechanic said the turbo was not 100% and showed me that the fan inside the turbo has play. I grabbed the fan and tried to wiggle it. It does have play but the play is very, very minimal. I’ve noticed no hoses collapsing when revving the engine while under the hood. The turbo gauge on the dash shows 50% when you floor the gas pedal while driving. The turbo gauge never get’s near the red.

Any one out there have a suggestion as to what is the source of this problem? Is the turbo bad if the turbo gauge on the dash never approaches the red? Could it be something else? Thank you.

How long have you had this car? If you’ve had it a long time, do you remember that it had more power?

There are both electrical and mechanical controls on the turbo boost. If you are using regular gas a knock sensor could be cutting off the power and limiting turbo boost. There is also a turbo waste gate which most likely mechanical on this era car to keep the turbo from putting too much boost and pressure into the engine. Waste gates can get stuck due to heat and corrosion and it might not be working properly.

The 4 cylinder turbo was not a motor you take to the drag races, so I wonder if you perhaps expect too much from this old mill? Try some premium gas and see what happens.

I’ve had the car for 10 years. When I first drove it, it accelerated fine. (I know it’s not a race car…it’s a wagon!) 6 years ago…it was at a shop that was robbed of all the catalytic converters on the property…including mine. I was given the exhaust parts to install myself, but, I parked the car in my garage for 4 years. To get it back on the road, I ended up replacing the in-tank and in-line fuel pumps, filter, and gas tank…after trying to run it with bad gas. I know…“stoopid”. I’ve tested the used converter and it’s working fine. I’d like to sell the car, but, I KNOW the acceleration problem will be a deal breaker. I DO use regular gas, although, at times I used to put in premium, but, because the car has turned into such a stone, that seems like a waste of money. The car will get up to speed on the highway, eventually, but, when we first got it…we nick-named it “Peppy”. It’s no longer peppy. More like grandpa.

Thank you for the advice. I will check into the knock sensor and the turbo waste gate. Those are two things I did not know about until your communication. (I’ve put premium gas in it recently with no effect.)

Thank you again.