Well, I think I fixed it!

My truck is a 2002 Ram, 85,000 miles. I have twin Edelbrock 160 GPH lift pumps with check valves so by just flipping switches in the cab, I can run either pump or both pumps.

I had been getting the dead pedal and the P0216 code. Not often at first, but over the last 10,000 miles it became so frequent that I couldn't drive more than a mile without dead pedal.

The P0216 code is related to pump timing, so I suspected the timing piston.

First I removed the top computer box together with the two solenoids on the rear of the pump so I didn't need to cut any wires. Mind the delicate ribbon cable when removing the computer sensor from the black metal piece.

I noticed the wires from the computer to the small solenoid were losing their insulation, as if heat had made it brittle and it was just falling off of the wires.
It was so bad, I was really surprised that it hadn't already shorted out and fried the transistor inside the computer. I repaired the wires using teflon insulation and heat shrink tubing.

Shame on Bosch for using such poor quality wire.

Then, with the pump vertical, delivery valves up, pry evenly on two opposite corners of the square rear plate to remove the high pressure pump and distributor. Keep this assembly vertical as you remove it and be careful not to let the three pistons fall out of the shaft. I used a rubber band to keep them in, then put this whole assembly aside. Note the rotation, the pistons ride on the three rollers. Remove the three rollers and note the two ends of each roller are different, so you can reassemble the rollers as they were, not upside down.

Next remove the large bearing, it comes out easily as long as you work it out straight and evenly. Then the top and bottom guide plates for the rollers.

Now you can see the wavy ring and piston. Remove the piston cover from the side of the case. Then pull or pry out the plug and large spring.

The wavy ring has a bulb shaped dowel on the bottom which engages the timing piston, so when the piston moves, it rotates the ring. Note that the ring also has a pin which engages the black metal piece that the computer sensor mounts on. The piston and dowel must be centered in order for the wavy ring to come out. The piston was stuck so I had to use a bit of force to center it so the wavy ring could come out. No further dis-assembly is required, no need to disturb anything forward of the wavy ring, vane pump, brass gear, etc.

Now the piston can come out, but it did not move smoothly.
I could feel sharp ragged edges of the ports inside the brass cylinder. They had left brass fused to the surface of the piston. IMHO there is no excuse for this poor workmanship by Bosch. I guess it would have cost them a couple of dollars per pump to properly finish the parts in manufacture. Using 2000 grit paper, I cleaned and polished the piston and the inside of the brass cylinder, taking extra care to smooth and polish the sharp ragged edges of the ports.

Then I used WD-40 and lint free cloth to clean the piston and cylinder very well. You want to make sure you clean any residue from the 2000 grit. Replace the piston into the cylinder using a small flat blade screwdriver to compress the piston ring.

Now the piston should move as smooth as glass.

I reassembled the pump, put it back on the engine and it fired right up.
Test drive had no dead pedal and no codes, the truck runs perfectly now.

Not only did I save big bucks, but maybe now that I've addressed the root cause of the P0216 code, this pump will run for a few hundred thousand miles instead of the usual 50,000 ~ 80,000 miles typical of a new pump (with exceptionally poor workmanship courtesy of Bosh).

I'll try to update this thread after I've put some more miles on the truck, but so far so good.

Some pictures, not mine: http://www.turbodieselregister.com/u...&albumid=17275

My pictures:

 

THAT is a sweet write up. Congrats on your abilities and craftsmanship.

 

Nice work.

How did you end up with a vp44 on a 2004?

 

Kurt,

Good catch.
Sorry it's a 2002, confused it with my car.

 

Great info & pics

 

Nice job on the write up and work.

At 85K was that the original pump?

I also am not impressed with the wiring coming off the solenoid...what cheap work on a device going on a diesel engine and underhood.

Not impressed with Bosch....

 

Sixslug,

Yes, it's the original pump.
Aside from the timing piston issue, I couldn't tell any difference from how I would expect the inside of a new pump to appear.
No sign of wear whatsoever.

I read about another guy who fixed the timing piston and his truck ran fine for a few months until his computer fried, so then he replaced his pump.
His post gave me the confidence to even try this fix. But now I wonder if it was the solenoid wiring that fried his computer, and how many other computers have been fried by this cheezy wiring, given that I've always heard that most pumps fail because of the electronics.

I've put almost a thousand miles on it since the fix and so far it's still running like new.

 

Most of the mechanical failures are due to water in fuel or poorly filtered fuel...

I think the other big reason is the solder going soft after a few thousand heat/cool cycles, or so I have read.

OR, maybe its just the wiring failing as you found.