Fuel Pump

[Richard240]

My 1981 Spyder 2000 fuel pump does not run. The car was in storage for 4 years. After changing fuel filters, and doing other renewal chores and fixes, it started and ran fine. Then one fine day the fuel pump just ran for about 20 seconds and shut down.
So far as I could tell, the fuel pump runs anytime the ignition switch was on. The AFM seemed to not be involved.
Any thoughts on where to start troubleshooting? There is no 12v pwr at the pump, grounds are good and there’s no power on either side of the 16v in-line fuse. Fuse holder continuity checks out.
I haven’t messed with the dual relay or the AFM.
Thanks

[azruss]

May want to double check with others, but i think the in-line fuse provides power to the dual relay coil. If you had power to the fuel pump with the ignition switch on, then someone probably by-passed the AFM and dual relay.

[spider2081]

Near the driver side engine mount there are 2 single wire push "bullet" type electrical connectors. One has brown wires and one has red wires. The brown wires feed C17 a 4 cavity connector usually located to the outboard side of the steering column behind the instrument cluster. C17 feeds the inline fuse for the fuel pump. Inline fuse should be near C17.
The single bullet connector near your left side engine mount is most likely your problem. Next would be C17 sometimes overheats and melts.
Hope this helps

[Richard240]

May want to double check with others, but i think the in-line fuse provides power to the dual relay coil. If you had power to the fuel pump with the ignition switch on, then someone probably by-passed the AFM and dual relay.

Thanks for the help. I haven't had time to mess with the problem since my post, but from all I have read the dual relay and AFM has probably been bypassed. In your experince, is it better to leave the by-pass in place or return the system to original - assuming I can figure out how to do that? I understand that the AFM swith is a safety feature which shuts off the fuel pump when the engine isn't cranking or running.

Assuming I leave the dual relay bypass in place, any thoughts on where to check for no 12v to the pump?

[Richard240]

Near the driver side engine mount there are 2 single wire push "bullet" type electrical connectors. One has brown wires and one has red wires. The brown wires feed C17 a 4 cavity connector usually located to the outboard side of the steering column behind the instrument cluster. C17 feeds the inline fuse for the fuel pump. Inline fuse should be near C17.
The single bullet connector near your left side engine mount is most likely your problem. Next would be C17 sometimes overheats and melts.
Hope this helps

Thanks for the help. I haven't had time to do much since my post, but I checked the bullet connectors and they are clean and make good contact. I also checked the 4 cavity connector outboard of the steering column and reseated the connectors so it's good. But no 12v to the pump so far.

This may sound silly, but I have never been able to locate the fabled Dual Relay. I've looked all around the relay box behind the glove box, but can't see anything that resembles the diagrams and photos. Any hints where to look?

Since the fuel pump ran before when the ignition key was turned on, (it ran for a few days then just stopped suddenly after running about 15 sec) I assume the relay is bypassed, but at this point I am totally stumped.

Thanks again for the help!

[4uall]

this might help

http://www.artigue.com/fiat/

[azruss]

my dual relay was passed by the PO. I tested the relay and it was good, so wired everything back to stock. works like a champ.

[spider2081]

Did you drop the relay assembly down from under the glove box? There are 2 large screws under dash below the glove box door that hold up the relay panel.
The switch in the Air Flow Sensor can easily be adjusted to be on all the time. I would remove the black plastic cover from the AFS and look inside. You will see a mechanism that rotates. If you rotate it you will see the switch contacts on the front side of the mechanism. When you let go the contacts should open. With a slight rotation they should close.
You need to have voltage at the inline fuse for the pump to run.

[Richard240]

Thanks for all the help! I figured out what was happening. As you might imagine more than one thing.

After dropping the relay panel/pan under the dash, to my amazement it appeared that all the wiring and relays were absolutely as installed at the factory.

So I took a close look at the mechanical micro-switch on the AFM and discovered that it was stuck closed. A bit of emery cloth polishing fixed that. But then I could hear the pump going “thump” each time it was energized.

So I pulled the fuel pump and filer off. Drained the filter and pump which were both full of gunk. Looked like rusty water. Replaced the big can filter. Drained the fuel tank, of course, and got a bit more rust and stuff.

Then I put 12v to the fuel pump and ran the DC motor backwards – which blew stuff all over the place! Note: Next time aim at a bucket or can - and keep a fire extinguisher handy! Then ran it forwards and it worked just fine, smooth and even. Even used a bit of compressed air to make sure I cleared as much gunk as possible.

On the advice of Jake from International Auto Parts I installed an in-line filter BEFORE the pump.

So for now it’s running great! Just in time for the last of great New England fall weather. Or at least until things sludge up again.

Again, thanks for your great advice and help! You guys are great!

Dick Adams
Middletown, Rhode Island