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914World.com _ 914World Garage _ More fuel pump problems

Posted by: mxdude914 May 11 2005, 10:21 PM

I finally thought i had the fuel pump problem worked out but i was wrong. I traced it back to starting when i reconnected the brakelight wire that the p/o had cut, when i connected it, the brake light fuse would blow. I messed with it for a while and found that if i just cut the back up light wire the problem was solved. This is when the fuel pump started cutting out, then i thought it was fixed when it did it again, actually a few times after it warms up, then i just take the main relay out and put it back in and it will sometimes run for a minute or two. Sometimes it wont start back up unless i use a diff. relay. Does anyone have any explanations?

Posted by: mxdude914 May 12 2005, 09:51 PM

anyone?

Posted by: xsboost90 May 12 2005, 10:00 PM

are your taillights wired correct, i mean they work etc correct? Trace your taillight wires back to the board and see if there has been any tampering or splicing up there. Is your fuel pump in the front or rear? Could someone have ran a new wire and relocated the pump as ive seen before? Check your grounds! ok thats all i have.

Posted by: bd1308 May 12 2005, 10:01 PM

look closely at teh relay contacts, mine were rusted real bad.....i put dielectric gel everywhere to seal the thing.

Posted by: Borderline May 12 2005, 10:29 PM

I'm new around here and will try to help......someone will correct me if I'm wrong. the fuel pump circuit is a lttle complex. there is the solenoid and I believe a fuse on the relay board in the engine compartment. It is also connected to the fuel injection. The idea being that the fuel pump runs when the key is turned on and the engine is spinning. if you crash the car and the engine stops the fuel pump will stop too. the po on my 72 1.7 had connected the fuel pump to the aux connection on the ingition switch. Anyway there are several connections with the posibiltiy of corosion: the fuel pump relay. fuel pump fuse on the relay board in the engine compartment, fuel injection connector on the relay board (white wires), the main wiring harness connector on the relay board. I'm not sure why the taillights would effect the fuel pump. i actually have a broken wire on the main wiring harness connector...a real pita to find. good luck!!

Posted by: Dave_Darling May 13 2005, 01:10 PM

If your car has D-jetronic fuel injection (stock 1.7, stock 2.0) then Brand Anders has a troubleshooting flowchart for the fuel pump control system on his amazing D-jet website--http://members.rennlist.com/pbanders .

If your car has L-jetronic fuel injection (stock US-spec 1.8), the pump is controlled by the "dual relay" hanging off of the battery tray. The relay turns on the pump when either the starter is cranking (yellow wire from the ignition switch to the starter is "hot") or when the flap in the air-flow meter is open.

If your car is carb'ed, then you are totally at the mercy of whomever converted the car over to carbs. Find the pump and trace the wiring. Make notes as you go, then try to troubleshoot the wiring.

Sounds like someone's really been messing with the wiring for the lights....

--DD