'95 Volvo 940 "pings"?

palebeachbum

New Member
For the past 30k miles, my Mom's '95 Volvo 940 has developed a "pinging" problem that has gotten worse with time. She thought maybe the timing wasn't set properly, so she had the timing belt changed since it was due anyway. This didn't fix the problem and her Volvo mechanic told her the timing is self-adjusting, so it couldn't be the cause of the problem anyway. It occured to me that I notice the distinct smell of gasoline outside her car a lot of the time. Could this "pinging" and gas smell be caused by a bad/leaking fuel injector? The car has 172k miles and runs very well otherwise. The "pinging" and gas smell are worse some days and not present other days. What's going on?
 

Mad Jack

Rookie
There is a knock sensor located on the engine block. This sensor has gone bad.

This sensor listens for knocks and pings and adjusts the ignition timing to compensate.

The pinging sound you hear is detonation. A condition where the fuel / air mixture self ignites before the spark plug fires. This problem, if allowed to continue, can cause burned valves and or pistons.

I'm sorry but I can not tell you the exact location of this sensor on this engine.

Until you can get the sensor replaced, use at least 93 octane fuel to help reduce the detonation.
 

friedach

Rookie
The V has an anti knock sensor-have it checked. you are doing some serious abuse to the motor. If sensor ok, might have to test EMU. BTW what fuel are you running-V's usually need top grade stuff, NON ethanol-it damages the rubbers! Mechanic is right, but if sensor not working, timing will keep advancing beyond what is safe. Gas smell-do you have a sealing gascap? is the smell under the bonnet? injector leaks go into motor, but you may have some plumbing problem-test fuel pressure with gauge-look for drop off after switch off. Look for stains, they'll tell you where leaks are. The injector rubber collars might have shrunk/perished a bit, renewal is allways good. Bad mileage, poor starting indicate fuel leakage sometimes. check hoses under bonnet-make sure they're all connected firmly, & without cracks.
 
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