missile2511

My left front blinker was not working so I pulled the lens to check the bulb and realized that the bulb would glow but not light so I assumed I had a short or a bad ground. While I was checking the rear left directional I discovered that whenever I turn on the left blinker I can hear the fuel pump come on and run. It does not come on with the right blinker, only the left and the left blinkers run very dimly. How in the world did the left blinkers get crossed up with the fuel pump?

extanker

a wiring diagram would aid you to find out when these 2 circuits come close to one another. has any work been done on the car just before it acting up ? check the usual suspects...grounds,rodent damage etc

the flyin' scotsman

what year and model of car?

missile2511

This is a 1984 US with a recently transplanted 1983 euro m28/11 engine. Change included CIS injection on the new engine, which required new higher pressure fuel pump. I am not sure if the electrical problem existed before the fuel pump change or not.

davek9

The Turn signal and Fuel pump wiring are all in the same rear wiring harness that runs along (inside) the right hand side of the car, maybe a short between the two circuits in that same harness.

Was the Amp rating higher on the new pump that was installed? If so the supporting wire may not have handled it if the correct fuse wasn't installed to protect the wire, just a thought.

Here is a pic of the harness, when I replaced one that was all butchered up by the PO.

Note: right next to the right rear upper shock mount there is a rubber plug where the fuel sender and pump wires go under the car from the main run up to the CE under the dash.

Dave K

missile2511

Thank you very much Dave. I will check it out tomorrow. The new pump was installed at the shop by what I believe to be a very good Porsche mechanic, but the new pump is much higher output and may have caused a problem. The counter point is that the problem may have existed with the old pump and I just did not notice it. I have only put about 100 miles on the car since I bought it in August.
Joe

Alan

Most likely a poor ground connection near the fuel pump relay...

Have you removed the CE panel recently...

Alan