Will the member please come forward that sent me the VP44...

So what causes the hard start when hot? Or better said what is damaged when you have low pressure that in turn causes hard starts when hot? My vp44 is a year old it started having hard starts in the summer. My fass has only given me 14 PSI at the most since it was new but since learning more about all this fass sent me a new spring and I'm at up to 18 now. I'm running correct pressure now and have rewired lift pump to kick off during cranking does my vp44 have a shorter life now?

Edited December 19, 201410 yr by lrhull

Ifhull

lack of fuel flow through the vp causes over time a transistor to heat up and fail. below is what many say is the fix but none of us has tried it yet.

 

at 3:45 on first vid he starts talking about it.  then 9:05 shows the transistor that fries.

https://www.youtube.com/watch?v=8Efwk_lER2g

 

funny thing is that his transistor has more wires going to it while the one below has less...

 

the second vid

https://www.youtube.com/watch?v=jUq-d_HbGu0

 

when mine goes belly up, i will attempt this repair as im very good in micro soldering and such.  But i will remove the whole pump and not take it apart like the guy in the first vid did.

Funny part after pulling apart a VP44 the mechanical part is really easy to rebuild its just the calibration that is the hang up.

Then why not by-pass the electronics and make it purely mechanical? Is that even possible though?

Less mileage perhaps but more reliable in the long run.

Edited December 19, 201410 yr by JAG1

The electronics are what control the timing advance & fueling, through EWM solenoids. If you want all mechanical, you need a P pump oe VE pump. It is just not possible. I am also getting skeptical about this "repair", as my spare PSG has a MOSFET that has 4 wires & the one in the picture has 3 wires. Also, the factory one is held to the heat sink by the plastic case to the aluminum case for heat sink purposes. What holds this one down?

 

Ed

Hey, what 'moves', rotates, or spirals to actually change the timing? I mean, what is moved in the head or rotor to do the actual 'work' of changing the timing??? And what is the force that does this change?

The timing piston slides in its bore to twist thee cam ring to new timing position either advanced or retard.

I've seen those videos before and I've 'fixed' a few control units that have had bad solder joints/connections. The job looks straight foreword. My question is what transistor is that and where do you get one?

The timing piston slides in its bore to twist thee cam ring to new timing position either advanced or retard.

Ok. I understand that now. thanks.

So, what is the 'force' behind the piston. What controls the pressure of the fuel that moves the piston. Is this where the solenoid shut off the flow of fuel, which increases the pressure, which moves the piston.. and when the solenoid opens, pressure is released and piston goes back to original.. Or vice versa.. depending on whereabouts of the solenoid?

I've seen those videos before and I've 'fixed' a few control units that have had bad solder joints/connections. The job looks straight foreword. My question is what transistor is that and where do you get one?

I understand that you just match the number of color bands, their location and colors the same, would be an exact match on the transistor.

It would be nice, if in an emergency, that you could just cross some wires... hot wired you could call it and get the truck back home.

That would be better than always driving round thinking.... ''Gee, I hope it makes it.''

Edited January 9, 201510 yr by JAG1

I have a VP44 apart & personally, I think it will be impossible to properly replace the MOSFETS. The plastic casing, which holds them down is riveted to the base.  Also, how to remove the silicone goo that's covering everything? Surely, you cannot get a good solder joint with it in theere.

 

Ed

Well Ed...

Could you just build a new board and stick it in there instead.

Be nice if it was just plug and play as well.

And while you are at it...put the electronics in a little box somewhere else that is easily accessed and repaired / replaced.

Chris

Ummm...been reading on some jetta forums and those boys in Europe have had the VP44s on a lot ov things for some time.

Some of them mention the 5.9 Cummins has lots of electronic mods available, this I understand.

Would a VP44 from an european engine share any parts with a VP44 on a Cummins.

Specifically the electronics...lots and I mean lots of those pumps around i could play with.

Chris

http://nearbus.net/wiki/index.php?title=File:Resistor_color_codes.jpg Resistors have the different color bands. The color coding is how many Ω of resistance there is in that resister. Transistors are marked differently.     

 

To clean the 'Silicon goo' off you can use a stiff auto detail brush but don't be to aggressive with it.

Edited January 11, 201510 yr by IBMobile