Through the years I seem to go through a fuel pump relay every year or 18 months. It's always the same problem . When I pull the relay there is always a burn mark on pin # 80. It doesn't seem to matter which brand relay I buy . So considering I just turned 370K miles and still have the original fuel pump I'm going to replace it. I've replaced the in tank pump as the rubber boot split and I still hear it running so I'm think there is a high resistance with the old pump. I'll see how it works out.

 

more than a few cases of aftermarket in-tank pumps that come wired backwards :-O this means they suck when they should be pushing. A rather extensive treatise on them... In the Tank - 240 Volvo Tank Pump and Sender (the 240 uses almost the same setup as the 740, albeit with a somewhat different tank access plate).

 

Check the resistance on the grounds for the pump and the relay.

 

volvo 240 Mods and Fixes

Do this and be done.

 

Interesting and I have not seen that before. I guess I can also mount the relay near the fuel pump and run a fused hot wire to it. Thanks

 

the fuel pump under the car is not a happy place for a relay. anyways, the tank pump is wired to its own fuse already...

I dunno, those fuel pump relays aren't /that/ expensive and if you get decent Stielbel ones, they last many years, this 'mod' seems a bit silly to me.

 

I agree thats a nice mod. I hadn't seen it either but I've seen that done in machinery when we had failing relays on boards.

if the pin on the relay went black it probably also heated the spade connector in the socket. when the connectors get hot and blackened they loose tension exasperating the issue. adding a second relay would take the load off the first, but at any rate you might be able to replace the spade connector and not just the relay.

 

btw, that mod is also harder to do on a 740, where the fuel pump relay is in the main relay panel behind the ashtray.

note, late production 940's did away with the fancy dual fuel relay. instead, they use the Radio Suppression relay under the hood as the 'main' relay, and have a separate simple common relay in position "M" as the pump relay. but converting an older 7/9 would be hard as relay M has no pins, and you'd need to run a power wire from the RSR for the ECU and other stuff.

 

hard to get tot he spade connectors too. I think you can take the panel out or shift it around but it's awkward in there.. the first time I tried to assces the pump relay it I had to search for the screw that holds the little tray thing near the lighter, until finally I realized there is a little black plastic piece that pops off to reveal the screw. Aha! Simple when you know it's there but I bet many got stuck looking for how the little plastic tray thing comes out.