while driving to work my engine light came on, after work i stopped at advanced auto and let them check it, a p1688 internal fuel injection pump controller malfunction, everything i've read says the pump is out or going out, other than the engine light my truck runs great, 2 days ago i replaced the turbo, it has a fuel pressure gauge but i'm not sure if it is working right, it was install per manufactures directions, at idle it reads 30, at road speeds it's 24-25 psi, anyone have any answers, thanks

 

If you haven't go to Blue Chip Diesels site and review his trouble shooting guide. Then if you still have questions, give them a call, I found them to be very helpful.

 

Is this the original factory VP? How many miles on the VP? What fuel pump do you have? What gauge set up are you using?