Hi, My 1981 fiat has sat in the car body shop for over 5 years. I finally got the car back home and want to start putting it back together. Before I do this I wanted to be sure the engin runs after all these years sitting idle. I have a new fuel tank, pump and filter. The car will start on the cold start injector but then dies. If I keep the starter motor running the car continues to run. Will I damage the starter motor by doing this and is it possible to clear the injectors by running the engin this way?

One possibility is that your ignition switch is going bad. I'm not familiar with the '81 switch, but on the earlier ones, the power for the ignition coil are separate contacts through the switch, one for when the starter motor is running, and one set of contacts when the switch is in the "Run" position. What can happen with a flaky switch is that the contacts to power the ignition coil are OK in the start position (starter motor running), but when you release the key, the ignition coil loses its power and the engine dies.

And yes, you will eventually damage your starter motor if you keep running it when the engine is running. The starter motor is only meant to spin at a certain maximum speed, but when the engine starts and is revved, the starter motor (if still engaged to the flywheel) is forced to spin at much higher speeds than it was designed for, and it will burn out.

-Bryan

Thank you for the advice. I have a new ignition switch so I'll fit it this weekend and see what happens.

Let us know what you find out.

By the way, a slight correction to my earlier post: It's not that there are separate switch contacts for the power to the ignition coil, just that the internal electrical mechanism operates slightly differently whether the switch is in "start" or "run". At least on the earlier switches.

-Bryan

One step forward and two steps backwards. After an epic struggle, I managed to remove the original ignition switch from the steering column. I was ready to instal the new ignition switch but stopped because I noticed there ate two white wires connected to the inside of the original switch. Do you have any idea what is the function of these wires? I tried e to upload a photo of the switch but I must be doing something wrong!

Pretty sure those wires are for the seatbelt chime/buzzer.

Yes, the two white wires are for the "remove key" part of the ignition switch, and they are all part of the seatbelt / remove key / perhaps various other warning buzzers/chimes. No harm if your new switch doesn't have this, but you would have to do some rewiring if you still wanted the warnings (although hardly anyone ever does).

-Bryan

Thank you again for your help. I didn't sat in my earlier post but after trying to get the old switch out and then putting it back in again, the fuel pump refused to work and I have no power to the dashboard..... I will keep at it!

Fiat spiders are very rare here in France. Fiat started selling the Europa version towards the end but nearly all the early spiders are US imports. Mine came from Florida via Belgium.

Those 2 white wires also power the radio.

Eureka! With the new ignition switch the car now starts again on the cold start injector but will not stay running. I'm not too worried about the power for the radio. In the worse case maybe I could draw power from somewhere else? So now I know the fuel pump is working but maybe there is not enough pressure to take over from the cold start. I will do a pressure test unless anyone has a better line of attack. I have one more question. Is it normal for the fuel pump to work continually? Is this what the return fuel hose if for?

Is it normal for the fuel pump to work continually?

My first suggestion is to join the website Mirafiori.com They have a library that is free to members and membership is free also.

In the library are wire diagrams, owners manuals and other data. The is a Fiat publication that titled:
"Spider 2000 Electrical Diagnostic Manual 1980-1981"
This manual has wonderful circuit explanations and troubleshooting suggestions.

Originally the fuel pump would run with the ignition switch in the "Run" or "Start" positions of the ignition switch. Inside the Air flow Meter there is a switch that needs air flow to close and then it powers the dual relay that in turn powers the fuel pump. The Air Flow meter flap would need to be open for its internal fuel pump switch to power the dual relay that then powers the fuel pump.
Is the ignition switch you recently installed a Sipea brand switch or is it an after market switch made for a Lada? The after market switches do require some rewiring to work like the original Sepia switch.
To the best of my knowledge Sipea used 2 white wires coming out of the bottom of the switch to a 2 pin connector. for the key in switch warning buzzer. The cars side of the 2 pin connector should have a red/black wire and an orange white wire.

I will join the forum as you suggest. Your explanation is very clear, so I will try and work my way through the problem. I purchased the ignition switch from Spider point in Germany. It is slightly different to the original Sepia switch I removed so, it probably is an aftermarket. I can't find a name on the new switch at all. On the tab that locks into the steering column there are some numbers etc. but nothing else. Anyway, I am happy the car is at least starting on the cold start injector so hopefully I will be able to sort out the problem.

I have a 1981 fuel injected Spider also so I am familiar with the systems.
If you like you can email me directly: flyme194@gmail.com