I have the walbro pump with the simflo bypass regulator on my 02. Fuel pressure is great except when I first start it up. It runs around 15 idling but when I take off it will go to 0. Once it settles down it will go up to 15 and stay. It seems to do it when it has set overnight but not during the day when it may set for a few hours. It has me confused, I had a different regulator on it and thought that was the problem but it wasn't. Any help would be appreciated!

 

Do you have an electric pressure gauge? Where is the sender plumbed in? In any case I personally would not worry about that as long as you get steady pressure under normal driving conditions.
-P

 

I have an electric with the sending unit coming off of the inlet on the vp. What bothers me is you may drive a couple of miles before it desides to stay at 15 psi. When it does get steady it will jump right up. I thought it might be the computer doing it so it is wired to a fuse that is on when switch is on. I think I'm going to get another pump and try that. I can use this one for a spare.

 

gwhammy,

I have the same set up as you except I have a mechanical fuel pressure guage and I have been have the same problem as you describe for the past 9 months or so. It has been driving me nuts because I can't track it down. I'm thinking maybe air is getting into the fuel lines at the Simflo pressure adjustment threads because I do get a drip of diesel from there but I can't seem to stop it even with a new rubber o-ring. I have no idea.

Mark

 

Mine did it with a different pressure regulator. If I let it idle for a few minutes the fuel pressure is fine. Do you think it could have something to do with the pressure regulator inside the pump?

 

Hmm. I would suspect the electric sending unit and test it out by connecting a mechanical gauge, and trust the mechanical one. If it duplicates the problem I would look at the LP, otherwise it is the sender.

 

I just bought a new sender for another truck, I'll try that this weekend. Thanks