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Fix your own Volvo fuel relay

volvo fuel relay

How to fix your volvo fuel relay.

If your engine isn’t getting the proper amount of fuel, especially as the temperature dips, it could be your Volvo fuel relay. The solder joints in the relay itself tends to shrink and crack rending the relay non-functional. This thread tells you where to find the relay and how to resolder the joints and change the capacitors in the relay. You can avoid buying the expensive Volvo fuel relay pump if you follow the instructions here!

Just wanted you to know, that thanks to Lee I found the problem. It was indeed the #103 relay that gone bad! I even managed to fix it. Here is what you need to do if you have the same problem:
1. Pop the cover off and carefully examine the little circuit board.
2. Look around every solder connection, especially the larger components and
terminals for tiny hairline crack that forms a circle right where the solder meets the component lead.
3. If you locate one, simply flow some fresh rosin-core solder from a decent hot soldering iron into the joint and resolder it. It’s probably a good idea to resolder everything once you are in there, as there aren’t that many joints.
4. Look for bad contacts on the relay part itself, intermittent (open) relay coil, or intermittent component failure. (Junction breakdown on a Transistor, etc)
5. while you are in there, Replace the capacitors. This is extremely important. The capacitors in my case were the problem. They became temp sensitive and simply stop performing in low temp. After I replaced them and reinstalled the relay the engine starts great!!!

MVS Forum Member guy200 says:

The problem was with the capacitors not the resistors. They capacitors look like the one in the pic. There are 2 of them solderd on the circuit board. These are very common capacitors so you can locate them at your local electronic technician shop.

MVS Forum Member aloggia adds:

Hey all – I wanted to let everyone know that replacing the fuel relay seemed to have fixed my problem as well. It’s been warm here in VA and I won’t feel 100% confident until the temps go down to 30 degrees but I’m at 99% now. I took the easy way out and bought a new one; I didn’t feel like messing with solder.

Fix your own fuel pump relay

1 Comment

Jean st felix says:

once and for all where is the fuel pump r-e-l-a-y fuse for an 2002 volvo s40 no one has a clue and am not talking about the fuel pump fuse

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