I have a few questions about VP44 failures. As I understand it the electronics are what normally fail not mechancial problems. I have seen alot of VP44 fail even when the get the proper fuel pressure and fuel flow.

I know on mine when the VP44 started to fail I could go in and monitor the voltage with a DRB and I was getting less than 12V at the pump and it was hard to start. If I hooked a battery charger up and had more than 12V at the pump it would start just fine.

Also when I worked at Dodge I had several trucks coming in throwing the P0216 code because the relay that supplied power to the VP44 was failing.

Has anyone tried monitoring the voltage at the pump to see if it might be causing the electronics to fail because of improper voltage?

 

as I understand it. (copied from a post at another forum)

The housings on the VP44 wear out due to bad lift pumps causing the diaphragm in the front of the pump to rupture and the result in a short time is the housing wears to the point that fuel bypasses the piston and full advance cannot be accomplished which causes the code 216 and causes the truck to run erratically. This makes perfect sense to me as it explains why as 24 valve trucks get older the fuel mileage goes down steadily, and when we replace the injection pump with one that has a new case we get the mileage back! In a typical rebuild, if the case isn't worn out completely and the timing can be reached on the test stand then it passes the test and a partly worn out case gets to the customer, just to fail sooner.

The other issue is the computer on the top of the injection pump. The computer gets intermittent and eventually dies because of too many heat cycles. When you shut the truck off the latent heat in the engine heats up the computer and after many heat cycles the solder that holds the electrical components to the circuit board becomes crystalline and no longer makes a good electrical connection causing intermittent drivability issues, and eventual pump failure.

 

Yeah what he said,and some kinda fuel treatment for the truck aint a bad Idea,thanks to the low sulfer fuel,my two cents

 

Try mixing 1 quart of 2 cycle oil to a 35 gallon tank of fuel... The results are a quietier engine, lube for both pumps, and better MPG numbers.