Ok, I have a Westach 0-15 PSI Fuel pressure Gauge on my 2000 CTD.

I am trying to determine if I have a LP going out or if my Sending unit is to blame.

It will Occasionally read 9 psi at Idle and 7 at WOT.

But most of the Time it will read what it has always read 13-15 PSI at Idle and 9-12 at WOT.

Do lift pumps work good sometimes and bad at others when they are on their way out or is this a case of a failing Sending unit?

I have an aftermarket warranty and occasional lack of power (Injection pump?) so if it is going I am going to let it go all the way and have both replaced.

Dan

 

My bad lift pump was coming and going. I replaced it with a FASS II yesterday.

 

I have heard of people having this problem. They have good pressure and then it will drop. These are signs that the lift pump is going bad.

 

I would suggest using a manual gauge along side your electric gauge. I was having strange readings with my westach when I first installed it so I hooked up a manual on the other shrader valve on the pump and noticed a huge difference at times. The electric gauge would drop to 5psi and then to 0psi and back up to 13-15 . The manual gauge never skipped a beat so I knew it was the sending unit.

Hope this helps.... Doug