1981 Spider FI quits

[chuckcloutier]

Still trying to figure this one out. The car runs absolutely great for a day or 2 and then it will quit, while driving, for no reason (well, of course, there is a reason, I just can't figure out what it is). I'm looking at replacing the coolant temp sensors (all 3) There is one critical one in the T in the front of the motor and 2 in the top if the IM between the spark plugs. Any suggestions where I can get these? Any other ideas? Does my thought process sound logical?

Love this car but it's driving me to drink!

[So Cal Mark]

don't waste your time and money on the sensors in the top of the head, they only send a signal to the temp gauge and have no effect on how the engine runs. The sensor in the tee can cause your problem, but a faulty connector is more likely than a sensor with an intermittent problem. When the car stalls, will it restart right away? Have you been able to check for spark after it stalls? The inline fuse for the fuel pump can also cause intermittent trouble

[chuckcloutier]

After it stalls, it's hard to start, can sometimes take 5 minutes to get it to start. Where is the inline fuse for the fuel pump?

[majicwrench]

You need to test things --spark, fuel-- when it stalls BEFORE you go replacing parts, or checking fuses.
Keith

[So Cal Mark]

the inline fuse is near the steering column, under the dash. It's common for the fuse holder to deteriorate internally

[rlux4]

I had an intermittent quit or no start problem when I first got my car and it turned out to be the inline fuse holder that Mark is talking about. It looses contact and that stops power to the fuel pump. It's on a brown with white stripe wire behind the main fuse panel amongst the rat's nest of wires there. That wire goes to the dual relay.
This may not be your problem, but you need to know where this fuse is anyway, if it's out the car won't run.
Ron

[BPFiat]

Mine did that (1981 Spider FI) and the magnetic pick up to the distributor was replaced and that solved the problem. Check for broken/missing insulation on the wiring.

[chuckcloutier]

It was the distributor. Put one of those nice fancy (and expensive) ones in from IAP and the car runs great.

[GeorgeT]

I'd bet on a failing Double Relay.

[richfolsom]

I had a similar issue and found out that the tube coming out of the gas tank to the vent (below the gas cap) had fallen into the gas, which wouldn't let air in. I would driving along no problem, then it would sputter out. If I opened the gas cap and closed it, it would run fine. Not sure if this would apply to you, but it's a very easy check.

[chuckcloutier]

Actually started happening again, replaced the ignition switch and that fixed it for good.

[burlybryan]

Thanks for following up. It's always helpful to know how repairs (especially electrical) work out.