Fiat Won't Start

[tedy]

I just had some work done on my 81 Spider. While it was at the repair shop the fuel pump gave up. The shop put a new pump in and it drove home fine (about two weeks ago). I went to start it today and it would not start. It turned over and ran for about 15 seconds and quit. I have fuel, I have spark, and it cranks just fine. I checked the fuel pump fuse and it is ok. I am going to check to see if I have 12v at the pump next, but I was wondering if you can hear or feel the pump running if you turn the key to the on position?

The odds of a brand new pump going bad are slim, but it is possible.

Tedy

[RRoller123]

If it is wired as original, the pump turns on only when the AFM flap moves, i.e. the engine is cranking over and drawing air. MANY cars have had them alternatively wired up to turn on when the key is on, so can't give you a sure answer. I do hear mine, but lots of folks say they should be quiet. Others will have to chime in on this too.

[DanD]

It has been a while, but doesn't the combi relay shunt the power to the fuel pump from a different source when the starter is turning over, and then the relay switches over to the contact in the air fuel meter when the key returns to the run position.

A lot of people wire the fuel pump so that it is running whenever the ignition is on, as the combi relay is not cheap, and they don't always know about the contacts in the AFM. However, it should be noted that the reason the fuel pump is switched to the AFM is so that the fuel pump will shut off in an accident. If the engine isn't running, the flappy closes, and the contact is broken.

One last thing. the GROUND for the fuel pump is grounded to one of the studs on the driver's side tail light. This is a poor ground location, and it is easy to have problems with the fuel pump because of this. I pretty much move it in any spider I work on.

[carl]

The pump should be running either with the starter motor engaged or with the flap on the AFM open with the key in the run position. You should be able to put your hand on the pump and feel it running. Get someone to turn the ignition switch to the start position or remove the air filter box and prop open the AFM flap while the ignition key is in the run position and you should be able to feel the pump running.

[tedy]

Thanks for all the good info. I'll give these a try this weekend. I am keeping my fingers crossed that my fuel tank is not full of junk and jamming the pump.

Tedy