After 3rd consecutive stop, my focus will not stay running It turns over but shuts off promptly. AFter one hour it starts again without a problem. IT does this only in the summer, but it has never overheated,and it has never left a code.,
I replaced the following
Battery, alternator, fuel pump,
fuel pump relay, themostat and housing, crank and cam sensor, oxygen sensor
What could the problem be?
Why did you replace those parts?
I take it the starter turns but the car doesn’t start, when you say that it doesn’t start?
It would help greatly to know the year, mileage, and maintenance history of the Focus.
It sounds like you have an ignition component becoming heat sensitive. Coils will often do this, as well as igniters. It typically shows up in hot weather and when you shut a car down, becaue your underhood temperature rises after you shut the engine off. The exhaust manifold, the exhaust pipes, and areas around the cylinders are far higher than the spot where the temp sensor is, by hundreds of degrees, and once the coolant stops flowing and the fan stops blowing that heat migrates out of the exhaust system and the engine and heats up the areas around them.
Any tech worth his patch shoud be able to easily diagnose this problem, but we can’t accurately do so over the internet. It’ll take measuring equipment to check the ignition signals, or at least a hands-on look-see to see if you’re getting spark.
My guess is fuel pump, but why guess, make your second stop a mechanic, so they can diagnose it failure mode and pinpoint the problem.
The focus has 169,000 miles and the problem started approx. 25,000 miles ago. It has been well maintained ie. oil change every 3,000 miles. In addition to the repairs mentioned above, the coil pack, ignition wires and plugs have been changed too. The water pump is new and the cooling system is working perfectly.
Could it be the temp sensor, fuel pump relay, the ignition switch, or the two fan relays? The car doesn’t overheat, but I should also note that the fans typically don’t come on when I come to a stop after it’s been running.
Numerous mechanics have checked it out and hooked it up to their diagnostic computers, but they have not gotten a code or made a correct diagnosis.
PS. It’s a 2001 Focus