i have a 2002 cummins with a vp44 hot rod injector pump, a bd deisel max flow pick up pump, afe cold air intake and intake horn, edge ez, and recently added smarty s-03. the rough idle started after the vp44 hot rod pump. it smooths out with the a/c on when warmed up, and with the a/c off when cool. any help would be greatly appreciated.

 

That is normal for a hot rod pump. Same goes for the Dragon fire extreme vp44 and that pump uses the .093 Connector Tubes & .093 Injection Lines.

 

thanks. i didnt change the stock lines. shoul i have?

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Should I have changed the stock lines?

 

No leave the stock line's it will make it worst idle wise.

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Next thing to do is to protect the vp44 do you have a fuel pressure gauge and a good lift pump ?

 

yeah. i have a bd max flow that is acting up, the low pressure fuel gauge varies from 5-30 psi sporadically jumping around. the replacement will be here tomorrow. hopefully that fixes it. btw they said the new pump needs to be installed motor side up and fuel side down to prevent problems.

 

You need a snubber between your gauge and the vp44 the jumping around is the pulse's from the vp44. Don't let the fuel pressure drop below 10 psi at WOT.

 

Is that the piece that the sending unit threads into and goes through the banjo bolt?