Non starting hot H1
 

I have a 1994 H1 and have owned it for several years. Recently it has developed a SEVERE starting problem...which is worse when it is hot out, than when cold. When the engine is cold, the wait light/start sequence will work properly and the engine will start. In hot weather (or when the engine is hot), the engine will NOT start after the light goes out....if it even comes on. I have to wait.....sometimes for hours....until ithe engine cools off enough, and then the light/start sequence will work just fine. I have spent almost $1000 on this problem at the local "certified" repair shop and yet the problem still persists. In New Mexico sumer heat typically is in the ninetys or more and I have had to wait until evening to even think about getting the machine to start. This is not a good thing obviously. Has any one else experienced this behavior? Let me know on this forum please. signed...Desperate In The Desert. (ElRover47@ msnm.com)

I have the same problem with my 1994 H1. It won't restart until it cools. Did you ever solve it?

I would look at replacing the PMD first. If that doesn't solve it, then possibly the injector pump (less likely to be the problem). I have heard many occasions of this same issue. There was one other odd situation I saw where another H1 owner had a starter that was causing the problem only when hot as well. I guess it couldn't create enough RPMs when hot, only when cooled down.

I would recommend purchasing a new PMD if you haven't already. You can leave the old one mounted where it is (because it is a pain to remove), and just disconnect the harness from it, and get a remote mounting kit with heatsink for the new one and install it in a cool area near the batteries or windshield washer tank using an extension harness.

Check for engine codes, and look at this post: http://www.predatorinc.com/hummer-bl...m-dan-fsd-pmd/

PMD and remote mounting kit: http://bluehummer.com/pmdrekit.html

A 94 doesn't have a PMD.

I thought they started using them on the 94's? Are you sure?

They only went on the turbo diesel motors and they didn't go into H1s until 1996.

Oh, I wasn't aware. Maybe I've just noticed because some people did engine swaps with newer engines.

One of the advantages of the older trucks is that they are mechanical and don't have the electrical issues the later models do. Downside is they don't have the power of the later models.

I had this issue and solved it
 

I have a 94 and it would not start when hot. You can test this by getting the engine hot, then shut it down, then pour tap water over the fuel injector pump. Does it start? If so, it is the fuel injector pump and it needs to be rebuilt.