Ghosts! Fuel Pump Keeps Running After Car Turned Off

GDATL · Post by **GDATL** » 15 Jul 2010, 17:21

I was getting ready to leave for a few days, driving wife's 2006 S80 2.5. Last night in my garage I heard a small motor running (high pitched whine) and when I crawled around the car, the source is near a small cylinder just behind the lift point near the passenger side rear of the car. I started the car and let it run for a few minutes then turned the engine off to see if it would stop. After the fan turned off, and all the other noises died dow, that motor sound continued - no key is in the ignition!

The car is a certified Volvo with 2 yrs and 30,000 miles remaining on the extended warranty, but I just didn't have time to take it in today. Late this afternoon, the noise was still there -- has never stopped. Now I thought that this cylinder was the fuel filter, but I'm not certain. When I put my hand on the cylinder (fuel filter?) there is no vibration/warmth, and it doesn't seem like that is exactly the source of the sound, even though the source is obviously very near-by.

I thought that the S80 fuel pump was on top of the fuel tank, but maybe I'm wrong. If that is the case, I don't have access to it, but I am very suspicious that it is the fuel pump constantly running and not turning off, even when the car has been turned off for hours! What would cause this? Any other ideas of what it might be?

I decided to drive my other car, so I am leaving the S80 unattended for a few days. Now I am worried about this starting a fire in my garage while I am away. Would you recommend pulling the fuse for the fuel pump and if that stops it, leave it out until we take the car in for service?

Thanks!

GDATL · Post by **GDATL** » 15 Jul 2010, 18:03

No replies, so I pulled the fuel pump fuse, and the noise stopped. Must be a faulty relay or something on the fuel pump. I'm leaving the car in the garage over the weekend with the fuel pump fuse pulled. Will replace it and drive to dealer on Tuesday morning. Shouldn't be a problem, right?

oughorian · Post by **oughorian** » 15 Jul 2010, 19:44

You did right if by pulling the fuse out you stoped the pump then it is ok to wait as long as needed , I think you are right about the pump relay might be a sticky one.

GDATL · Post by **GDATL** » 28 Jul 2010, 11:41

Update: After leaving the fuse out and the car garaged for 5 days, we re-inserted the fuse. The fuel pump did not start and the car started normally, ran normally and turned off normally. We took the car in to our Volvo dealer and they never saw the problem. They indicated that there are no TSBs on this problem and that since they did not experience any failures that Volvo would not authorize any repairs or replacements. Hopefully we will never experience the problem again; although Murphy tells me that it won't happen until after the extended warranty expires at 100,000 miles!

Post by **mvsuzr** » 08 Aug 2010, 10:08

Just a couple of thoughts if it comes back:

Check for fuel leaks. There's a recall on some earlier models for a fuel pump flange that can fail. If you see or smell gas, remove that fuse (if you can do it safely) and call the dealer.

What commands the fuel pump to come on? I'm not sure of the method used, but one way is to sense low pressure in the fuel lines. Perhaps the sensor is the problem?

Chalenac · Post by **Chalenac** » 07 Sep 2010, 12:11

S80 2006 / 55,000 Thank you for posting this as I have had a similar experience. My motor continued to run after I shut the engine off. After calling the dealership and explaining to the mechanic he tried to convince me the noise was a fan motor. I explained the noise did not sound like a fan motor, and I had started the vehicle again and then turned the ignition off. This situation continued sporadically, and then my check engine light appeared.
I took my vehicle to the dealership for a diagnostic check and they advised I needed a fuel pump. The diagnostic code stated EMC 2900 Fuel Pressure signal to low. I inquired if it was the fuel pressure regulator but was assured it was not as the regulator was tested separately. I definitely needed a new fuel pump.
When driving my vehicle from the dealership (I was two blocks away) I noticed for the first time my left blinker was double blinking. I returned to the dealership only for them to tell me the turn signal had a short in it. Are they connected?

Any advise - where do I go from here?