Fuel Pump Wiring - Help requried.

[ThomasJ]

Decided my 81 was too far gone so I just picked up an '80 FI. The PO (one prior to whom I bought it from) rewired the tail lights by cutting all the plugs, removing the circuit boards and soldered the wires to the bulb housings; after some work with grounds and fuses it all works! Under the dash I found 3 toggle switches, I have discovered that two of them operate the radiator fan (why 2??) and the third switch appears to be a hot wire that runs directly to the fuel pump. At the fuel pump both of the original wires have been cut with the new hot wire being connected to one of the terminals on the pump but on the other terminal there is about four inches of wire just hanging there, do not know where it was connected or where it should be connected to. Electrical is not my strong point so any help will be most appreciated.

My longer term goal is to get all wiring back to original but for this summer I would like to drive it before a total rebuild.

Thanks in advance,
Thomas

[rlux4]

The green with black stripe wire comes from the dual relay to supply power. Ther other, white with black stripe wire goes to ground. Unfortunately it's pretty common to find a PO has bypassed the original wiring through the dual relay due to a failure to diagnose a starting problem. Safety is the reason for the original wiring. If the engine stops running, as in an accident, the dual relay looses a signal from the AFM as the flap closes and opens the circuit to the fuel pump, stopping the flow of fuel to the engine.
Also, it's common to find a manual switch for the fan installed in case the temp. sensor fails. I put one in on an ill-fated trip to Mirafiori "Oregon 08" trip when my car overheated. After I fixed the problem I left the wiring and switch in place, disconnected, in case something happens while on a trip.
A pic of original wiring:

Ron

[ThomasJ]

Thanks Ron for the detailed explanation, I will ground the white and hopefully it will work. Looking forward to fixing it correctly but for now can't wait to get it running!

Follow-up: Put the white wire to ground as suggested works great. Draining the old gas looking forward to trying to start it, been sitting for two years.

Thomas

[dantye]

If someone wired a switch to turn on the fuel pump, they probably failed to properly diagnose and repair a problem with either the ECU, Dual Relay, or the AFM. My problem was the AFM. It had to be opened up and the contacts adjusted because the fuel pump was running any time the ignition key was on, whether the engine was running or not - A DANGEROUS CONDITION.
Although it is "factory sealed," you can use a sharp box knife to finally loosen up the sealant enough to remove the AFM plastic cover (just make sure to clean and re-seal it with a silicone bead when finished).
Here is the thread that helped me, http://forum.fiatspider.com/f08/viewtop ... FM#p111186and the photo of what I adjusted to get the pump to turn on ONLY when it was running, not anytime the key was on:
https://picasaweb.google.com/dantye/FIA ... 5004338418

Search "Artigue" on this forum, download his manual and you will learn a lot about electrical, air and fuel troubleshooting on Fuel Injected Spiders.

Good luck - you are half way there just by using this forum!

[ThomasJ]

Great information and very much appreciated. My winter project will be to get all the wiring back to stock.

Thomas