Ok, so I've read as many threads about in-tank fuel pumps being bad as I possibly could, but nothing seems to fit, so here we go.

About two months ago, my son's '81 245 began dying after being driven for a short distance. It simply wouldn't restart immediately after being turned off... sometimes. Finally, as it was becoming a major nuisance, I checked the fuel pump relay and sure enough, the black plastic connector was melted and the relay was pitted on one terminal. So we replaced it and it worked fine... until the other day. The relay looks good, but I'm wondering if it's one of the fuel pumps that have gone bad. Normally when you turn the key slightly a buzzing sound comes from the back of the car for about 2 seconds, right? At least that's what happens with my 240. Is that buzz from the in-tank pump or the main pump? I'm going to need to replace something but I have no idea how to even diagnose it. Any help is appreciated.

 

For an 81, if you put a jumper wire on the left sides of fuses 5 and 7, both pumps will run constantly. You should then be able to listen to them both running. I would clean both of those fuses while there.

 

Ok, cool. It's fuses 4 and 6 on this car. So, the car started finally when I rigged the jumper. So now what? How do I tell if it's the in-tank pump or the main pump? My guess would be it's the one that normally buzzes when you turn the key, but I don't know which one that is. And, is this jumper going to have an adverse affect on the electrical system and/or the good pump?

 

This is an 81, right? The jumper wire by-passes the fuel pump relay and the blade fuse by the coil. Can you hear both pumps running with the jumper?