Will not start when hot

CMJALLTHEWAY

MEMBER
1989 CHEVROLET SILVERADO
5.7L
V8
4WD
AUTOMATIC
153,000 MILES

Turn off ignition when hot and it won't start. Will start when hot with starting fluid. Vehicle has TBI. Starts fine when cooled off. Is vapor lock possible in this kind of fuel delivery system? I Don't know. Just hoping someone has encountered this issue before and was able to successfully diagnose and fix the problem. Thanks in advance for any information.

Friday, September 10th, 2021 AT 3:23 PM

1 Reply

JACOBANDNICKOLAS

MECHANIC
110,127 POSTS

Hi,

We need to determine if it is a fuel-related issue or an ignition system issue.

This vehicle has an Ignition Control Module in the distributor that may be going bad. Also, there is a pick-up coil in the distributor that can be going bad. Both of these components can be adversely affected by heat. Once it cools off, it will work again.

So, when it won't start, see if it starts for a couple of seconds using starting fluid. If it does, then we know it's fuel-related. If it doesn't, then it's likely ignition-related.

I attached an exploded view below of the distributor. I highlighted the two components I'm referring to. If starting fluid doesn't change things, check for spark. Here is a link that shows how it's done:

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

Let me know what you find.

Joe

See pic below.

Image (Click to make bigger)