'80Fi Hot Start Issue

[courtenay]

My car is now sitting dead in a friend's driveway. Went for a nice long drive on a hot day and stopped at a friend's place for a beverage. Car wouldn't start. Cranks really well, but nothing. As a techno idiot - I'm at a bit of a loss as to where to even start on this one. The car ran really well for about an hour. One thing I did notice was that when I turned the key on to crank, there was no sound from the fuel pump - should I have heard something?
Any suggestions as to how I might troubleshoot this thing would be greatly appreciated.

[focodave]

Bruce,
The fuel pump may or may not be your problem.
If you want to check it, though, there are a few things you could do.
The pump will not run unless air is flowing through the AFM. So when you are cranking the engine to start it, the pump is supposed to run because enough air is flowing through the AFM to move the flap which is connected to a set of contact points that energize the fuel pump circuit.
If you are trying to crank the engine and listen for the pump to run, by yourself sitting in the car, you may not hear the pump over the engine cranking sound(s).
So you may need another person to either crank the engine while you feel the fuel pump --- or have the other person feel the pump while you crank the engine.
Another way you can test the pump is to run a jumper wire from the hot side of the battery to the appropriate terminal on the pump itself to see if it energizes.
That would test the pump, only.
It would not test all of the circuitry in the fuel pump system.
You still have a fuse, dual-relay, AFM contact points, etc. in the circuit.
Dave

[rlux4]

Hey Bruce,
Bummer.
It does sound like a fuel issue. But it could also be that the injectors aren't pulsing. There's a good diagnostic for checking the power going into and out of the dual relay here: http://www.wcmotors.com/personal/Fiat%2 ... agnostics/
If the pump isn't running when the car is cranking you could hot wire it as Dave suggests to get it home. If the pump is running but it's not starting it's a good bet the injectors aren't pulsing. Do you have a noid light? Pull a connector, crank the engine and see if the light pulses. Without a noid light a volt meter would work, but I never had much luck with them, the pulse is so weak and fast.
Let us know what you find.
Ron

[courtenay]

Thanks guys. Question, though, this happened about 5 minutes after I shut the car off after running for about an hour - very smoothly. No hint of fuel issues - the car pulled strongly through all gears. Had it up over 110KMs/Hr (about 70 mph). It will be sitting in my buddies garage overnight and I'll go give it a shot in the morning. Hopefully it will start. If not, I guess I'll be towing it home for some serious diagnostics. Unfortunately it's at the bottom of an uphill driveway!

[rlux4]

A no start can come on suddenly for various reasons. The inline fuse for the dual relay/fuel pump power can blow for example. Also check that the boot isn't loose at the air flow meter or intake plenum.
Ron

[courtenay]

Thanks, Ron - I am heading off soon to see if the car will start. Where should I look for the fuse for the fuel pump relay?

[Kevin1]

Same thing happened to our '80FI last sumer. The in line fuse (red plastic housing), below the dash on the driver's side, blew. Seems it went when I turned the key to restart it after driving it all afternoon running errands. Anyway, that got it going and it hasn't done it again.

[courtenay]

Not the fuse. The car started right up this morning and ran strong for the 5 mile run home. There's something going on that doesn't react well when the engine is stopped when hot. Would the AFM was sticking open when I shut the car off - then releasing closed after it cools down cause the problem? On a similar problem post, Alsgro talked about the cold start injector possibly being the problem - but it isn't clear whether that did turn out to be.
I'm stumped, so any other suggestions would be appreciated.

[rlux4]

I suppose that's possible, I've never seen it happen though. It wouldn't hurt to take the AFM off and check the plenum. Look for grime or any sign of rubbing of the flap on the plenum walls. Make sure the flap moves smoothly throughout the entire range of it's movement. It wouldn't hurt to find the location of the inline fuse also. It's on a brown wire with a white stripe. Find the wire up in the rat's nest of wires behind the fuse panel and follow it to the fuse holder. Be sure you have an extra fuse with you at all times for it, if it blows the car will not start because you'll have no fuel flow.It can be hard to find the first time. I looked a long time before I found it tucked up on top of a brace under the dash.
Ron