Engine shuts off when the weather is hot outside?

Hello, I'm Danny.

It sounds like you might have a weak or failing fuel pump not providing adequate fuel pressure. I would suggest performing a fuel pressure test. Here is a tutorial showing what is involved:

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

After performing this test get back to us with the results and we'll go from there. I've attached a picture below showing the proper fuel pressure for your truck. Hope this helps and thanks for using 2CarPros.

Billy,

This could be a couple of things, but where I suggest starting is at the crankshaft position sensor (CKP). When these sensors start to fail, they are adversely affected by heat. The engine actually will lose spark. Once the sensor cools and contracts internally, it will work again. The excessive heat causes them to expand internally and lose contact.

First, take a look through this link and let me know if it seems to mirror what you experience.

https://www.2carpros.com/articles/symptoms-of-a-bad-crankshaft-sensor

Now, if that seems to mirror what you experience, the easiest thing to do is this. When the engine stalls, check for spark to the spark plugs. If there is no spark, the sensor is the most likely cause. Also, if you have a live data scan tool, you can check for an RPM signal. One last thing, if you have a tachometer in the vehicle, see if there is any movement in it when cranking the engine when it doesn't start.

Now, because of the model year, the pick-up coil, in the distributor, functions as the CKP. There is also a TFI module on the outside of the distributor, but they either work or they don't. If it's bad, it won't run even after cool down. That leaves the pick-up coil.

I attached a pic below of the distributor. I highlighted the pick-up coil and the TFI. At this point, what I need to know is if spark is lost to the plugs. If you don't have a tachometer in the truck or a live data scan tool. here is a link that shows how to check for ignition spark:

https://www.2carpros.com/articles/how-to-test-an-ignition-system

Try that and let me know what you find.

Joe

See pic below.

Okay, thanks. I will check, but the thing is; after it shuts down on me, if I hear only one fuel pump kick in when I turn the key on,it won't start , but I know it's going to start when I hear two fuel pumps kick in. That's why I was thinking it was a fuel issue.

Interesting. That does sound fuel-related. Try this so we can confirm. When it won't start, see if it starts and then stalls when you use starting fluid. If it does, we know it's fuel-related. Also, try cycling the key on and off a few times to see if that changes things.

Let me know.

Joe

Hello again.

Just an FYI. Just because you hear the fuel pump working that doesn't necessarily mean it's performing at its optimum capacity. As I suggest in my prior post I would perform a fuel pressure test to verify the fuel pressure to see if the fuel pump is providing the proper fuel pressure. I've attached the fuel pressure specification below again for your truck. Get back to us with the results and we'll go from there. We're here to help. Hope this helps and thanks again for using 2CarPros.

Danny-