Spider will not start after reaching normal temp.

[ed153a]

The Spider will start just fine in the morning, however after reaching normal operating temp if I turn the engine off and wait about five minutes the engine will not start again. Starter is turning the engine strong. If I push start it though the car will start right up and idle well.
If I am in a situation where I can't push start it with help or roll down hill I have to wait until it has cooled down to the point about where the temp gauge is at one quarter to one third of the full range then the engine will start again.
The following is a list of what I have replaced and tested so far:
Replaced:
Ign. cont. module, Ign coil, plugs, wire set, cold start temp sensor
Tested:
Battery, alternator, both ok.
I have chased spark and it seems that it is not being produced from the distributor. So the question now, is this an indicator of a failing mag pickup? Timing? Or something else entirely

Thank you for your time and the info. All of you have made this site invaluable.

[ed153a]

Some detail that I failed to mention is that the car is a 1980 124 Spider FI.
Thanks again

[So Cal Mark]

the pickup unit in the dizzy can fail when hot, just like the ign module. It's not as common, and should act up when running too, not just running. There is a substantial heat soak after shutting down a hot engine though. The odd thing would be that you can push start it, If there is no spark you shouldn't be able to push start. I'm assuming your car is FI. You may have an injector leaking which causes a flooded condtion when trying to restart

[ed153a]

Another detail is that the car will start right away multiple times if I do it almost imediatly after shut down.
Is there a way to test fuel injectors while installed?

[So Cal Mark]

the only way is to do a pressure drop test with the engine off to determine if the injectors hold pressure

[kristoj]

I had a similar issue with my '82 -- would start when hot, but only if I restarted it within 5 minutes or so. If I let it sit more than 15-20 minutes, it would not restart. Turns out I had a bad thermo-time switch and it was turning on the cold start injector when the vehicle was hot, thereby flooding the engine. Don't know if this is your culprit, but the next time it won't start, try unplugging the cold start injector and see if it doesn't fire up. If it does, you may also have a bad thermo-time switch.

[ed153a]

As per your suggestion John I tried that once again to see if I could get it started. No luck. I have replaced the thermo time switch already but had called the part incorrectly in my origional post. I read your earlier posts trying to diagnose the problem and had also removed the cold start injector to see if it was spraying while hot. It tested ok.
Soooo, I'm back on the issue of the pick up or the injectors that Mike had mentioned.
Another thought is that at times when I try to start the engine the starter just buzzes. Now if I just turn the key position to off and try to start the car again it usually works fine. It may take a couple times occasionally but usualy once is enough. From what I understand again from reading posts here is that this is an indicator of the starter selenoid going bad. Do you think it could it be affected by temp. also?

Thanks, Ed

[So Cal Mark]

buzzing in the starter is more likely an issue with the starter armature or windings than a solenoid problem. And, starter problems are normally worse when hot, especially if the trouble is with the field coils. First though you need to check voltage to the starter under load. Low voltage will prevent the starter from operating and can cause it to buzz

[ed153a]

Thanks Mark,
I do beleive low voltage is part of the problem.
That's an interesting thought with the field coils and I'll look deeper into that.
Man, I am driving a big can of worms!

Ed

[spider2081]

Just asking, but if an injector is stuck open causing a flooded condition;
If you remove the spark plugs when it won't start would they be wet with fuel??
would there be a fuel smell in the oil if the car contionusly floods, wouldn't fuel get in the oil??
when the car does start wouldn't it smoke as it burned out the remaining excess fuel??
I am not suggesting a stuck injector is not the problem only trying to think of other indications this might be the fault.

[So Cal Mark]

not a stuck injector, but a leaking injector. I've never seen an inj stick open, always get varnished shut. But deposits on the pintle can cause them to leak. If the leak is big enough, the plug would be wet. But you'd be surprised how minor the leak can be and cause a flooded condition. Usually the heat of the engine will turn the fuel to vapor in the cylinder.
Unless you remove the injection rail and keep the fuel hoses attached and pressurize the system, the only way to check for a leak is to attach a pressure gauge and see if it holds pressure when shut off.
Another possibility is that either the check valve in the pump or the pressue regulator lets pressure bleed off and you get vapor lock in the fuel rail. Still need to install a pressure gauge and see if it holds

[spider2081]

Thanks Mark, I would like to put a fuel pressure guage in the rail of my FI 81 Spider. Most of the guages don't have the range to measure in the area of 40 lbs. Those that do are quite expensive, close to $200. Electric oil pressure guages that read to 80 lbs are availible in the area of $40 with the sender. It shouldn't be too hard to modify a fuel rail to accept a pressure transducer. Has anyone ever tried using an electric oil pressure guage for fuel pressure??

[ed153a]

Update:
I was stumped and took the car to a mechanic. He said that I need to replace the ignition wiring harness. Durring his assesment he saw that there was no spark from the coil and suspects that a wire is grounding out from the ignition switch. Would I be able to isolate which wire and replace it?
Any suggestions in courses of action would be appretiated.
I'm leaving for Iraq in a couple of weeks and would like to put this problem to bed so I wouldn't have to deal with it upon my return.

[racydave]

Bad or burnt connections will cause a voltage drop, and can be intermittant and heat related. There is a connector for the ignition switch under the colum. Connections in this connector are a known PIA! If one looks burnt, you can butt-connect these wires. Also, I would remove and clean the wires to the starter, and clean the battery connections, AND, add a ground-strap from engine to chassis. Mark also suggested the harness in the distributor, do it! And please come home safe!!!