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Dead Truck

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Well I just had a bad day! While driving my truck passing someone up hill I lost all power so I coasted to the shoulder!:banghead: After checking for fuel at the injectors with #1 and #3 lines cracked loose and getting nothing I then went with the inlet line and broke it loose fuel sprayed everywhere! I called my buddy with his 2008 Chevy 1500 and with a tow strap we made it home!!!:banghead: Broke out the scanner and found a P0251 YIKES!!!:doh::banghead::doh: From what I found on this site that means I need a new VP44?!?!? :spend::shrug: Can someone please tell me I'm wrong??? If I'm not where is the best place to buy a new IP from? Thanks for the help in advance!

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Mine was more of a 24v swap than a p-pump swap. All the parts came off my 268k original 12v that sprung an oil-water leak somewhere in the block. Swapped the timing case, pump, lift pump, cam and some other bits onto a $440 24v in unknown condition with some crash damage out of a wrecked school bus. The stock cam swap was a mistake. Too little lift, it doesn't breathe well and runs hot for it. Stock untouched ISB 205 injectors in it. May do some RV275s at some point but I really have plenty of power already and I'm sure a Big Stick won't hurt it at all. I read that the pop pressure difference results in retarding the timing about 3*, I set the P7100 to a bit over 18* aiming for 15 effective. It starts in cold weather like it's timed at 18 though.

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so the stock 12v cam wasnt right? and I dont quite understand the timing just yet with a ppump? should the injectors be repopped? or just adjust timing accordingly like you did?

No issues with just adjusting timing that I've read. 12v cam doesn't have enough lift to flow well. Run the stock 24v cam of you're keeping an electric lift pump, that'd be fine.

  • Owner

so the stock 12v cam wasnt right? and I dont quite understand the timing just yet with a ppump? should the injectors be repopped? or just adjust timing accordingly like you did?

Yes you injectors have to be re-popped because of the lower pressure of the p-pump.

As for the p-pump where the gear is place on the pump shaft that is the timing its get all the way across the RPM span... As you see the pump shaft is nothing more that a camshaft.

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Now on the VE pump and VP44 pump they have a adjustable cam ring that move forward and backward in time to allow for timing changes. The VP44 is fully electronically controlled from ECM sensors and feedback and the old 12V had a single sensor for controlling the advancement cam and the rest was mechanical.

But the P-pump its static fixed. So if the initial timing is 13* BTDC thats the timing for all the RPM span...

VP44...

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Vp44 has a very dynamic timing table that is adjusted through engine coolant temp, Intake temp, boost pressure, throttle, and engine load. Yes I know the VP44 stock table is rather weak for MPG's why most people plug in a chip of some sort and get instant timing upgrade.

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    $1900.00 on a kit ,$1700.00 on a pump = 3600.00 plus miss and labor if you cant do it yourself . vp44 pump under a 1000.00. unless you got lots of cash the vp is the way to go for most who need there trucks for everyday trans for work ect. we do 2-3 converts a month here at the shop ,but it is for a very small group of guys looking to make the bigger numbers on the rollers or who are going pulling play toys . getting a 1000.00 for your old vp stuff i could use that phone number i got 30-35 cores here i would sell.

    Diesel Auto Power is a vendor on this site
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    Me either, my apologies. Maybe dealers/vendors should have an identifying mark.

    • Owner

    dont think he knew you were a dealer. i didnt know until your post above :)

    Me either, my apologies. Maybe dealers/vendors should have an identifying mark.

    Sorry guys during the change over of the ad banner software there was vendors that came up for renewal and the old software was diabled and the new software was in-complete. So I'll take "My Bad" for that one... :duh:
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