on 8/22/06 10:16 PM, David Brodbeck at [EMAIL PROTECTED] wrote: > Unless I'm mistaken, there are two pumps on his Volvo. One is the high > pressure pump, underneath the car. It's pretty easy to hear while > crouched next to the car. The other is the in-tank pump, which is best > heard by removing the fuel cap and listening through the filler neck. > Failure of the in-tank pump will result in some interesting symptoms, > sometimes including a car that only runs right when the tank is at least > half full.
You are correct. By this time (the car being a 1991), the main pump is usually audible from anywhere outside the car, with the ignition switch in the on position. When the pumps get old, you can even hear them at the rear of the car with the motor running (especially if the pre-pump has failed and the main pump is now working harder). The assortment of odd symptoms from pre-pump failure are most common on Turbo models, somewhat less so on the non-Turbos but they do happen. Someone else observed that blown distributor seals can also produce this behaviour, and that is true. However, if it's a turbo engine (or a VERY high mileage non-turbo one), then seal replacement is often only a temporary cure as often the issue is massive blowby that's blowing oil past all the motor's seals. Replacement of the distributor seals may only give another few months' service before the problem recurs. Just another few cents... Mac
