engine dies out - overheating?

[geecee]

Hello All!
After reading all the posts potentially related to my issue, experimenting with changes, diagnostics, etc. ….I give up and I have to ask.
My 1980 Spider FI girl “Bruna” is having trouble running. Long story short, I’ve been experiencing an issue with the engine, aka it dies down as if it didn’t have any power or ran out of gas.
The first time that happened it did it with some shaking and inconsistent up/down of power, almost like if I was stalling it because of lack of experience with manual transmission!!
Lately it’s been more like a loss of power to a complete turn off and stop. In the past two days it ran great in the morning on my way to work. In the evening on my way back home, one day it died after about 1.5 miles, and the following day after about 5 miles almost at home.
Both times, and also the very first time it happened, I parked her away in a safe area and called home for a ride planning to go back to get her when less traffic later in the evening. Every time it restarted and ran all the way back home like it never happened.
So it is temperature related. Also the first time it was the first warm spell of spring, and lately it’s been very warm in NC.
We tried it all! The FI system is relatively clean, meaning that when I bought her ~1 year ago, I had the fuel tank shop-cleaned and replaced both fuel filter and pump. The lines had been checked by PO and replaced in some parts. I replaced the charcoal cartridge and we gently blew compressed air in the fuel lines to clear any charcoal residue, cleaned valves, and replace fuel tank cap. I feel pretty confident there, but she is rusty in the under carriage area.
As for air intakes, most of the lines have been checked and replaced.
We diagnosed the voltage regulator and determined that it is not the problem, i.e.not battery overcharge and in general no electrical issues anywhere in the car.

So what is it? is something overheating or getting loose with a warmer engine?

[geecee]

Oh, forgot to mention that the cooling system seems to work fine. The temperature stays at 190F max and the radiator fan turn itself on and off when/as appropriate.

[TX82FIAT]

Coolant stays at 190. Car seems to stall when warm outside or alternatively stated car seems to stall recently after a short drive. Assuming the car starts up on its own after the stall with no need for a jump and you have tested the battery as well and the voltage regulator mentioned above.

When the car stalls is typically at a certain RPM range or speed? Is it a stall that consistently occurs within a certain amount of time after you start her, say 5 to 15 minutes after start up? You mentioned you owned if for about a year. Did you have any of these symptoms early in ownership? Did you store the car for a priod of time and this stall issue surfaced immediately after storage? Does the car run well up until it stalls through the RPM range and then just dies?

I don't think the problem is related to outside temp. The issue may be electrical with respect to the airflow meter functions. If the car is getting a wrong reading from one of the sensors once you reach operating temperature the computer thinks is in experiencing one consition and has mapping for that condition. However, the reality is not that condition creating a problem with the electronic fuel injection mapping based on a bad sensor. It could be mechnical as the air flow meter has a door that can become problematic if it is not moving through the entire range of motion. You could still have a vapor issue with the fuel lines that locks or impedes the flow of gas into the engine. You could even have an engine pressure issue although unlikely. It could be a lot of things. More detail is needed.

[hayesbd]

I don't have any experience with the FI cars, but it sounds very similar to a couple of familiar ignition problems. If you are running a distributor with points, the condensor may be shorting out as it warms up. I had this issue many years ago and it was an intermittent problem that gradually got worse, very similar to what you describe.

Another thought is to look at the ignition coil - they can become intermittent after warming up, leaving you stranded, only to start and run happily after waiting some period of time.

If either of these components are due for replacement anyway, you might just change them now to eliminate that possibility.

good luck,
Brian

[geecee]

Thanks TX82FIAT.
This issue is been just random.I did have the car for about a year but really I've been driving it just recently because taking care of restoring the electrical system.
First time it happened, we looked all over but found no issues. So I drove it around for an entire weekend without a problem.
Then this week...twice!
It does not happen after a set amount of time and the RPM doesn't seem to matter. What is strange is that it disappear as the car is allowed to cool down, and it never did it in the morning when the engine and the air are cooler.

I have not checked the Air Flow meter, or the ignition coil as a friend suggest. I will try to diagnose them this weekend possibly. What else?

[So Cal Mark]

I'd check the coolant temp sensor-both the connector and the sensor itself. To properly test the sensor you have to check resistance through the entire temp range. Loose connectors are a common issue with that sensor

[geecee]

Another thought is to look at the ignition coil - they can become intermittent after warming up, leaving you stranded, only to start and run happily after waiting some period of time.

If either of these components are due for replacement anyway, you might just change them now to eliminate that possibility.

Agree with you! Definitely the coil is going to get tested and possibly replaced.

[mgbgtn]

I had similar problem and it turned out to be the fuel filter. sedement from the tank would plug the filter and when the car stalled the sedement would setal to the bottom of the filter and the car would start up and run fine. It was worse after filling the tank which would stir up the sedement in the tank and get pulled into the filter.

[geecee]

I had the tank cleaned by a specialist and replaced the filter and pump.
You can never be extremely sure, but I would rule that out for now.

[geecee]

I'd check the coolant temp sensor-both the connector and the sensor itself. To properly test the sensor you have to check resistance through the entire temp range. Loose connectors are a common issue with that sensor

Mark, would that cause the engine to shut off?

[majicwrench]

Coils almost never fail, save your money.
Not speaking for Mark,, ,but,,Yes, coolant sensor can cause issues as can it's connector. Yes it can make car die. To test it properly is a bit technical, need lab scope or good volt meter and watch voltage rise and fall with temp. Just examining connector at sensor is good start, it shoud not have green goo on terminals and wires should be intact.
Most likely issue is ignition system failing when hot, when car dies that is the time to test things, other than that you are just guessing. Guessing, it could be dozens or things. The ignition module in the dist is a high failure rate item. When car is dead, pull a coil or plug wire and install spare plug, have someone crank and see if spark. Try this while car working well to get an idea of the spark you will see.
Keith

[4uall]

Took me a week to figure that this somewhat damaged connector was causing problems

[geecee]

I followed your suggestion and replace the coolant sensor! Not too bad, and I found a replacement sensor and a new connector (the plastic is crumbling) at the local Advanced Auto Parts for ~ $30 all together!
Still need to install the new connector and I'll test drive Bruna in the next couple of days. Keep you posted.

[geecee]

Success!
Thanks again for the suggestions. I drove her around for a couple of days now without the engine issue.
Still some problems with overheathing though. Now when I'm almost home in the evening, the two lights of the seatbelt and hand break come on and they do stay on. Something else when I thought that the electrical part was "cured".
Suggestions here? I saw a tread once about this other issue, but can't find it again. I'll search some more..

[geecee]

...or not!
I thought it was fixed by the new sensor, but it's happening again. This last time I took it to the garage and after two costly hours of fiddling with it he said it was the throttle position sensor and that I should just unpkug it. I did it and on my drive back home, guess what? It did it again.
It goes like this: no issue with starting, and drive great in the morning on my commute to work. The other day I even went out to grub lunch and had no issues. Then on my way back home...here we go again, start loosing power a bit at first and progressively gets worst, especially if I try a higher gear. I had to drive home on 2nd shift last time.. But even then, it shakes if I give it gas almost like I'm stalling it.

What is it??!! It's driving me crazy and I love this little car. HELP PLEASE!