S40T weird noise under hood

2002S4019T · Post by **2002S4019T** » 05 Jul 2014, 16:51

Hello, hoping I can get some helpful info until the manual I ordered arrives. There is a high pitched whine coming from a little gadget that is attached to the firewall under the fuse box on the drivers side. It also gets very hot. The frequency is the same as the sound that last a few seconds after first turning the key on. Is that a fuel pump? To be clear the car is a 2002 S40 1.9T.
Any advise is very much appreciated.

difflock54 · Post by **difflock54** » 05 Jul 2014, 17:48

Yes, sounds like the forward electric fuel pump.
I am not sure how hot they normally get but will check mine on next trip out.

2002S4019T · Post by **2002S4019T** » 05 Jul 2014, 19:01

Thank you, that gives me something to search for. I didn't know they had two fuel pumps. I think I might have posted this in the wrong place so my apologies.

difflock54 · Post by **difflock54** » 05 Jul 2014, 19:19

Apparently some do?
I dont know much about it myself but my V40 seems to be the same as your S40.
The front mounted inline pump is to achieve higher fuel pressure as required for efi systems I believe.
see the link below.
It might explain the heat issue you have noticed too.
http://www.justanswer.com/volvo/4banw-v ... y-hot.html

2002S4019T · Post by **2002S4019T** » 06 Jul 2014, 09:28

that link was very helpful, thank you. My car is running and idling fine so I think it's probably a problem with one of the pumps rather than the regulator. I think I might be able to change the main pump myself but I don't think I want to tackle the one in the tank. Did that on a Sebring once, no bueno.

2002S4019T · Post by **2002S4019T** » 09 Jul 2014, 15:39

Quick update, I thought some might be interested. Took the car in for service and the tech said he couldn't hear the problem. Went and picked it up an the noise had completely stopped. I even put a sound-scope on it and heard nothing and it's running fine. So either it cured itself, for now, or it is completely dead and the tank mounted pump is able to handle the load.