Archived Dead Tach, and poor running engine.

[Diesel Freak]

truck is a 2001 automatic. Has injectors, turbo and COMP box.



Today we hooked up the COMP wire and took the truck for a spin. All was great untill we went WOT, the tach went dead, but the truck pulled great, 43 PSI of boost and plenty of heat in the exhaust.



Pulled over to the side of the road, and the truck idled rough,, and wanted to die whenever you put it in gear.



We shut down the engine, and restarted it. The tach started working again, and it ran like it was brand new again.



We then went back to the garage and doublechecked all our wirng connections and disconnected the COMP wire.



We then took the truck for a spin, and the tach went dead again, and the rough idle reapeared.



We have not yet unplugged the COMP completely, but we think it could be a bad COMP Box, or a faulty CPS.



any assistance would be greatly appreciated!

 

[Sticks]

How's your fuel pressure? Some VP44's will die with in minutes of the wire tap.



Any codes in the ECM or PCM?

 

[Diesel Freak]

fuel pressure is good

 

[willyslover]

did you check the factory connection at the pump to make sure it was still tight . . the factory connectors aren't the best



did you almost cut the pump wire in half when you tapped into it ? [if you used scotch locks you might have]

 

[Diesel Freak]

The truck is fixed!



It was the CMP



Funny thing, on the Cummins box it says "Censor POS"