Questions and Answers

Ford Mustang Won't Restart When Hot Q. Dear Sir, I have a 1995 Ford Mustang 3.8 liter V-6 which I have cherished and brought over from the UK to here in Spain. I am thus without a mechanic with experience of the car. I am having an intermittent problem with the car re-starting when warm. Starting from cold is great.

After running, for say five kilometers, and then stopping somewhere, it does not want to start up again.

The temperature gauge shows the engine is overheating but not off the scale. It seems to need ten minutes or so to cool down and then it is fine. I have difficulty getting parts which I need to order on the net from you guys over the water, so I need to know what parts to try and change. I would be obliged for any help.

Raj
Marbella, Spain

A. I wish I could tell you exactly what is wrong and what you need to fix it, but in this venue that is impossible. The best I can do is offer the most likely possibilities based on my years of experience.

The first thing we need to determine is what is missing when it won't start, fuel or spark. When it won't start, take a vacuum line off the intake manifold and spray a good, healthy shot of carburetor cleaner directly into the intake manifold. Use that thin red straw that comes with the carburetor cleaner, it makes it a lot easier.

Then try to start it. If it starts and runs as long as the carburetor cleaner lasts, you know it's a fuel problem. If it doesn't, then it's an ignition problem. Take an old spark plug and gap it to about 0.100". This will be your spark tester. Take a spark plug wire and put it on the spark tester and lay it on something metal so the spark plug has a good ground.

Crank the engine. You should have a nice blue spark. If there is spark, then we know the ignition system is good. If not, we have an ignition problem.

Once we know which it is, we can go on and troubleshoot the problem.

It is possible that with an engine that is borderline overheating and has a bad Coolant Temperature Sensor, the PCM will lean out the mixture to the point where it won't start.

I would begin by replacing the thermostat and checking to cooling system over.