The truck won't run over 4500 rpm. Appears to run out of gas.

Fuel pressure was 50 at idle, didn't measure at any other level. It leaked down immediately after building up. Guage went to 50 and was down to 5 by the time I shut the key off and looked back under the hood. Suggestions as to why?

 

intank pump dead. Inline dead(assuming you are a return fuel system). Fuel Filter clogged. FPR somehow screwing up. Low voltage to pumps.

I'd go with dead intank.

 

The o-ring on the fuel pressure regulator is pinched, or somehow damaged otherwide.

Fual pumps are fine.

 

The FPR is the quickest and easiest thing to check. Run the truck for a while and after you turn it off, pull the vacuum line off the FPR. If it is wet inside you need to replace it. This was wrong with mine but all it only made the truck hard to start.

 

It's my understanding that to replace the o ring I need to remove the C clip and then what? Thanks, Jim (was installing that o ring part of the Radix install procedure... it rings as bell but I didn't do all the install work)

 

Yes, pull the C clip off, the regulator out and the o ring may or may not come out with it. It's very small, and green. It goes on that sall little nipple that goes into the fuel block.

 

Thanks for your help. Have to work evenings all week so I might not be able to make any progress until the weekend. Could this little o ring really be behind all these problems? Or just behind the "won't start on the first try" problem. I'm thinking fuel filter or the inline pump or or or or. One good thing.... it sounds like the problem is something I can work on as oppossed to some piece of computer technology that is beyond my ability to mess with. I can change a fuel filter or pump but to reprogram something or mess with the wiring.... lost puppy fits well.

 

In one word ... yes.

Check the o-ring, if I were a betting man, that's where I'd put my money. It won't take you but 20 minutes tops. Tale the O-ring out and replace it with a new one.

 

Keep an eye on your afr while "waiting" to take care of this problem. I don't remember you mentioning a starting problem, if you have issues with starting then the fpr is definitely up for being the culprit. Did you just install the radix? recently? Usually a bad fpr install comes into the equation pretty quickly. Keep everyone posted!! Get it fixed nevertheless...radix+low fuel=unhappy piston tops.

 

I'm with Flyer on this one. I bought my kit used. It already had a regultor installed, so I didn't check it out. After having some fueling issues, I checked the regulator and found the little center O-ring was pinched and cut.