Car Experts! What causes a car to not start in the heat?

Question

I have a 95 Ford Explorer and it runs just fine except when the weather gets hot, sometimes it has trouble starting. It starts and immediately dies. Sometimes it'll start if you put it in neutral and rev up the engine for a minute or two. It only does this when the weather gets hot outside. Any other time (Fall, Winter, at night, etc.) it starts just fine with no problems. It did this to me again today (it was about 90 degrees today). I made 3 stops previously in the day and it started fine and then I went to the post office, wasn't there 5 minutes and I came out and it started this. It's almost like the engine didn't have time to cool down or something, which shouldn't matter I wouldn't think. Everyone else's car at the post office started! Any ideas on what could be the reason?

Answer 1

It sounds like vapor lock.

http://en.wikipedia.org/wiki/Vapor_lock

Answer 2

Causes Of Car Not Starting

Answer 3

Could be a leaking fuel injector which causes the engine to flood with gas and be hard to start when the engine's real hot. One way to test for a flooded engine is to hold the accelerator pedal all the way to the floor (puts ECM computer in the "clear flood" mode and opens throttle plate all the way for max air intake) while cranking the engine for 10 seconds or so. If this helps start the engine, you will know that your engine is tending to flood in hot weather. A shop technician will install a fuel pressure gauge on your fuel injection rail and measure the fuel pressure both before and after you shut the engine down. The fuel pressure regulator is checked at the same time.

Answer 4

I'm surprised no one has piped up with this suggestion already -- Fords equipped with one are positively **infamous** for having their Ignition Control Modules go south, and heat is often what starts to set them off. At the onset, letting them cool down gets things going again. Eventually they fail outright and you're stuck. They're most likely to fail after you've shut down the engine on a hot day and the heat from the engine soaks into this component. In some years, they even moved them off the distributor and into the firewall to the outside air intake area to try to keep them cooler. Didn't seem to help.

This device picks up the fainter signal from a magnetic (Hall) sensor in your distributor and uses that signal to drive the larger current needed by your coil. Module goes south and you get no drive to the coil. No coil drive and you have no spark.

The lack of spark is easily tested by someone handy under the hood -- providing you're in "failure mode" (and if I'm right, I'm sorry to say that you will be again soon enough). Have them pull one plug wire and with a screwdriver, give it a path within an 1/8" or so of the frame, engine or other ground. As you try to start your vehicle, see whether or not there's any spark. I'm guessing not. If not, I'd venture to say you've got at least a 75% chance of having a bad ICM.

It's easy enough to check the module for anyone handy with a meter. They will be able to see the control signal from the distributor at the input of the ICM, but see no switching on the output side that goes to the coil while you crank your non-starting engine. A meter at the "tach" side of the coil will show the same thing.

The little bugger should be bolted to the side of your distributor with two screws and here's a picture of what it should look like:

http://www.partsamerica.com/productdetail.aspx?MfrCode=GPS&MfrPartNumber=EL173&PartType=194&PTSet=A

Not difficult to swap. I'm a bit surprised by the price, though. They used to be cheaper. The good news is that they fail so frequently that every auto parts store will be stocking them.


Best of luck.

Answer 5

i'm going to pass alongside with poultry's answer regarding the leaking gasoline injector danger. to help instruct it, the subsequent time it occurs, push the accelerator all a thank you to the floor and notice if it starts off extra effective. That opens your throttle plate huge open to allow as plenty air as achieveable into the engine and places your pc into the "sparkling flood" mode the place it stops injecting any further gasoline into your engine. whilst the engine's flooded, you do no longer desire any further gasoline! you besides could have a coolant temperature sensor that tells your pc how warm the engine is. in line with hazard you have an blunders code on your pc to help diagnose the subject.

Answer 6

i can only think of two things: the computer might be getting too hot, try finding it and cleaning it of debris (least likely to be the problem). or the choke is set incorrectly, I'm really no expert with fuel injection and as far as i know the computer controls all that. when is the last time you had a full tune-up (plugs, air filter, oil change, injectors cleaned/replaced, EGR/PCV valve)?