98 GMC 1500 p/u z71 stalling problem

[kenmatt]

I have a 98 GMC 1500 p/u 6.5l its new to me 258k after I put 500 miles on it, it started stalling periodically..I read on here that it points to the PMD (it has already been relocated) How would I know for sure with no gages, also the price varies, depending on where you get it between $80. And $400 what's the difference?

 

[WarWagon]

Where is the PMD mounted now? Extension cable? A spare PMD with a quality extension cable and heatsink is a good idea from a reputable vendor like Leroy Diesel @Burning oil . PMD located on the intake manifold is out of the frying pan into the fire. Wiggle test on any extension cable can show problems.

You cleaned the grounds lately?

Without gauges ... You need a way to test lift pump pressure to see if it's working while testing. I test my lift pump PSI every oil change with a pressure vac guage.

How old is the fuel filter? Fuel smell like gasoline or have water showing up when drained into a jar from the filter water drain?

Air in the fuel system is the #1 troubleshooting step. Put a clear return line on the IP and see if it has bubbles. Or blow $400 on a spare PMD and then start looking for air in the fuel system... Just saying: Air, grounds, then start troubleshooting...

 

[Will L.]

PMD is the achilles heel of the truck. No testing procedures for it, only "replace with known good" if that fixes it, that was the problem- So a spare pmd is just as if not more important than a spare tire.

Leroydiesel.com , a vendor here sells lifetime warranty ones and heatsinks, extension cable also. I suggest mount the spare pmd on a heat sink next to your existing one, then just move over the wire whenever you are questioning it. If bad then send in the bad one under warranty. So start with buying 1 from him for now. Many companies sell some as "best, etc" just get lifetime warranty for this thing.

Things to check before spending $:
Clean airfilter and fuel filter- measure volume of flow out bleeder valve.
Remove and clean all ground wires on engine- they mess with pmd/ecm bad.
Check for air in fuel line with clear tubing inplace of 1/4" return line out IP.

 

[kenmatt]

Where is the PMD mounted now? Extension cable? A spare PMD with a quality extension cable and heatsink is a good idea from a reputable vendor like Leroy Diesel @Burning oil . PMD located on the intake manifold is out of the frying pan into the fire. Wiggle test on any extension cable can show problems.

You cleaned the grounds lately?

Without gauges ... You need a way to test lift pump pressure to see if it's working while testing. I test my lift pump PSI every oil change with a pressure vac guage.

How old is the fuel filter? Fuel smell like gasoline or have water showing up when drained into a jar from the filter water drain?

Air in the fuel system is the #1 troubleshooting step. Put a clear return line on the IP and see if it has bubbles. Or blow $400 on a spare PMD and then start looking for air in the fuel system... Just saying: Air, grounds, then start troubleshooting...

Thanks Ken

PMD is the achilles heel of the truck. No testing procedures for it, only "replace with known good" if that fixes it, that was the problem- So a spare pmd is just as if not more important than a spare tire.

Leroydiesel.com , a vendor here sells lifetime warranty ones and heatsinks, extension cable also. I suggest mount the spare pmd on a heat sink next to your existing one, then just move over the wire whenever you are questioning it. If bad then send in the bad one under warranty. So start with buying 1 from him for now. Many companies sell some as "best, etc" just get lifetime warranty for this thing.

Things to check before spending $:
Clean airfilter and fuel filter- measure volume of flow out bleeder valve.
Remove and clean all ground wires on engine- they mess with pmd/ecm bad.
Check for air in fuel line with clear tubing inplace of 1/4" return line out IP.

Thanks Ken