My father in law recently gave my son a 1985 240DL that needed some monor work (complete tuneup etc.) and had fuel problems. He provided us with a new intank fuel pump as all the signs the car was exhibiting (one being that it wouldnt run after the tank got less than 1/2 full). I installed the new pump and cant get it to work when its hooked up to the pickup assembly. The pump does work when connected directly to a battery but when bolted up to the pickup assy. it doesnt. I had done several continunity test of the wiring and have found when the pump is hooked up I have a connection from the positive side to the ground....right now pulling my hair out wondering if the pump is bad? ( even though it works when hooked up directly) Continunity is good and correct when checking the positive and negitive connections on the pickup assy. when the pump is not attached. Any suggestions?

thanks

 

OK, so, the car was running, you are trying to put a new fuel pump which doesn't seem to work? If the old pump was running, albeit badly, and the new one doesn't work at all, then the new pump is bad.

 

if the new pump works hooked up directly to a power source but not when hooked up to the car, then you have a wiring or power problem. there's a fuse for the rear pump, is that good? there's a relay for both fuel pumps, is that good? all these things can be best tested with a volt meter and the wiring diagrams.

 

Many times the fuel tank sending unit assembly fails at the hermetic seal. An example can be found in photographs at this site:

In the Tank - 240 Volvo Tank Pump and Sender

Usually when this seal fails your fuel gauge will not work either.

On the other hand, if the fuel sending unit has been replaced with an aftermarket one, the wiring may be all wrong. I replaced my sending unit with an aftermarket one, I checked all the connections prior to installation and found two wiring errors. The black keyed connector had the two wires reversed and the two wires going to the fuel pump in the tank were reversed as well.