Shuts off while driving

Tiny
JEREMY M
  • MEMBER
  • 1998 MITSUBISHI ECLIPSE
  • 2.0L
  • 4 CYL
  • 2WD
  • MANUAL
  • 203,000 MILES
When I am driving the car after about thirty minutes it shuts down loses complete power. It will crank over but will not fire. If I let it sit for thirty or forty minutes it will start again, but then shuts off again.
Wednesday, September 26th, 2018 AT 7:47 PM

1 Reply

Tiny
HARRY P
  • MECHANIC
  • 2,293 POSTS
Well, most likely what is happening is something is heating up and then quitting. When the offending part cools off, it is able to function again. Often times, this happens to ignition coils (which supply the sparks that ignite the gas), or to the fuel pump. Either way, the car will not run correctly, if at all. So here is how to start the diagnostic process:

If the service engine light is on, it would be a great idea to stop at the local auto parts place and have them scan the vehicle and give you the code numbers. Yes, I would need the actual numbers, not just their descriptions. Otherwise, continue on.

Engines need several things in order to start. They need (1) fuel, (2) air, (3) compression, (4) sparks, and (5) 1-4 have to be on time, in the correct strength/amount. Unfortunately, when you get over 150,000 miles on any vehicle, any of those could be the problem. The most common causes are with (1) and (4).

I would start with simply listening for the sound of the fuel pump coming on. When you turn the key on, without turning the engine over, the pump should come on for two to three seconds. It makes a humming sound. If you can, get a helper to turn the key on while you listen for it. If you do not hear it come on, try tapping on the bottom of the tank with a hammer or other blunt object immediately after the helper turns the key on. If you then hear the pump come on, then you need a new fuel pump. Simple as that. You freed up the brushes in the electric motor inside the pump. This is a very temporary fix (might give you an hour or two of running time).

If you still do not hear the pump come on, then you need to check the fuses. There is a fuse box diagram attached below. The fuse box to look at is the one that is under the hood, along the left side. In particular, look at the fuses for "fuel pump", "ECM/TCM," "PWR Train," and "ENG Ign."

Just because the pump receives power and comes on, does not mean that it is pumping enough. We will circle back to checking the pressure output later on, if necessary.

If the pump is coming on, the next easy thing to check is for sparks. You can do this with a tester that is available at AutoZone or any other auto parts store. Here is a link for one on Amazon: https://www.amazon.com/Lisle-20610-Inline-Spark-Tester/dp/B0002STSC6/ref=sr_1_3?ie=UTF8&qid=1501325755&sr=8-3&keywords=spark+tester

Basically, you pull the plug wire off of the ignition coil (also pictured below) and plug in this tester between the coil and the plug wire. Then get someone to turn the key while you observe it. If it flashes, then you have spark. Check all of the cylinders.

Let us know and we will go from there. There are more advanced tests that you can do for free or very cheap. We will go through them if needed.

Our guide on checking for sparks: https://www.2carpros.com/articles/how-to-test-an-ignition-system

Our guide on fuel system checking: https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator
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Wednesday, September 26th, 2018 AT 9:00 PM

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