Hi guys.

About three months ago my truck's engine quit on me while driving, then it also suddenly quit while idling outside of my garage. I am located in Perú, so I ordered some parts from Rubber Duck 4x4 in the USA.

The car did not run for almost three months while I waited for the parts. I ordered a new fuel filter, a high output lift pump, a remote mounted PMD with a #7 resistor and new batteries.

As soon as i got the parts i started the engine to test how it was behaving before i changed the parts and it took a lot of cranking for the engine to start. After about 15 minutes the engine suddenly quit. i cranked it again and it started but quit after a few seconds, so my first choice was to replace the lift pump and see. I replaced it with the new one and purged the air from the fuel system and started the engine again, then after some minutes the engine quit again. So this time i replaced the fuel filter. The old filter was kind of dirty so i discarded it and installed the new one. I cranked the engine and it started then quit after a minute or so. Finally i decided to install the new remote mounted PMD, then i cranked the engine and it started right away and let it run for almost 4 hours and it never stalled, it was running perfectly.

I shut off the engine check the fuel lines for leaks and stuff and then tried to start the car again and it did not start, i kept it cranking many times until the batteries ran out of charge. The next day after recharging the batteries, i cranked the engine and after a few tries it started, i let it run for almost two hours, shut it down and tried to restart it again and same thing, it kept cranking but not starting. After 6 hours or so, i tried again and after a few attempts cranking it, the engine started. This time i went driving around the neighborhood and the car drove perfectly. Went back to the house , shut it down, tried to start it again, and i cranked it 'til the batteries died again with no success.

I have no clue what is going on. The PMD never gets hot since i mounted in the right side of the truck, opposed to where the batteries are bolted, right on the access door to the air conditioning hoses besides the radiator. It get plenty of air when the car is driven and is very far from engine heat.

I have to wait until the engine is cold and after many attempts cranking the engine it finally starts, it seems that when the engine get a little hot i get this problem but again when it cools down it takes a lot of cranking until the engine starts.

Could this be fuel related and not electrical? please help, there are no Hummer dealers in Lima and this H1 is one of the two that were sold to someone in Peru.

 

There have been 3 variants of FSD's:
1) FSD's with a 30214 on the case are the worst. This is the first generation and the most prone to fail.
2)***FSD's with a 34264 are second generation, they will either work, or won't work.
3) The third generation number 34583 was designed to allow you to "limp home" by operating for a short while and then fail.

Which one did you you replace it with?
Did you remember to remove the old transistor?

note: New FSD’s don’t come with resistors. It should be #5, you could replace with #9 for higher performance.

Did you use silicone grease instead of the heatsink pad compound?

 

Hey Palmid,

I got a whole new PMD with an incorporated heat sink that i mounted on the side of the radiator, the kit comes with #7 Resistor. I did not have to remove the old PMD, i just left it in place but i connected this new PMD box to the connector where the old one ( the one attached to the injector) was connected.

 

...most likely fuel related, have you checked the fuel solenoid and the fuel shut off solenoid.?

 

Send Hummech a PM. He will respond with a diagnosis or ask you more questions to help determine one.

 

...does it blow any white or excessive black smoke when started or running?