2001 cummins transfer pump voltage

[wagntagn]

Does anybody know the voltage when starting .When I turn the switch to on I m picking up 12 volts for 2 seconds & then it drops to 8 volts? Then when I turn the switch to start & let go I get 12 volts for 25 seconds then voltage drops to 8 volts? Why does it drop to 8 you would think it should drop to 0 volts.These test are done at the transfer pump connector.

[Blueox01]

does anybody know where to go to check voltage specs when turning ignition on & then start position,my voltage never drops to 0 it goes down to 8 volts only?

Not sure of your question.

[wagntagn]

what happen is I wanted to check the pressure between transfer pump & vp44 ,my gauge was reading 0 psi so I unplug connecter on transfer pump & check voltage with my meter and the results were with key on 12 volts for 2 seconds then voltage went down to 8 volts ?then I turned the switch to start & let go I was getting 12 volts for 25 seconds & then the voltage dropped to 8 volts until I turn switch to off ,voltage dropped to 0 ,why is it staying at 8 volts you would think it should drop to 0 volts.Afterwards I pull the pump out and it s seized so ordered a FASS pump as replacement,Ijust want to make sure of the good voltage before I do the switcharoo.

[volkswagon]

Sorry I can't help with your problem but welcome to the forum and what part of Canada are you from?

[wagntagn]

Up in the" BOONIES" northern Ontario,just bought the cummins with a defective transfer case,I did those repairs & now I want to make sure I have enough fuel press. before I start on the modifications.0 psi is not enough ,I ll replace the transfer pump,I m worried about the 8 volts I have when I flick the switch,this can be hard on a 12 volt pump

[Mopar1973Man]

Either its 0 Volts turned off or 12 Volts turned on... Full controlled by the ECM...

OFF should 0 Volts

Cranking should be modulated 12 Volts (Square wave)

Running should 12 Volts solid.

No there is no relay or other controllers. Either the ECM has a bad ground, poor power supply, or ECM is starting to fail.

[Mopar1973Man]

It's all ECM controlled... Normal pressures from a lift pump while cranking.

http-~~-//www.youtube.com/watch?v=NCJjMzRImpA

[wagntagn]

Great ,thanks for the info I ll check the ground to start:)