Fuel Pressure

94.5stroker · Feb 26, 2012

Ok guys for a little background, I have been chasing a fuel leak for some time now. I couldn't really find out where it was coming from, and the 10-15 dollars for fuel bowl rebuild kit was a lot cheaper than the $100 for a fuel pump, so I bought all of the orings to reseal the fuel bowl. After I pulled the bowl and replaced all of the oring/fuel lines, it was still leaking. But this time I was able to see that it was leaking from the fuel restriction sensor at the back of the fuel bowl (94) so I pulled it and replaced it with an 1/8" NPT plug. I figured surely this solved the problem. Wrong, it is still leaking (although not as bad)

Now for the new stuff...... I built a fuel pressure gauge and hooked it up to the fuel bowl. From a little bit of research on here I found that it should be at 50-60 psi idling and should drop a little bit at WOT. Well the first time I hooked it up I got 42 psi idling (the engine wasn't completely warmed up if that matters) and instead of dropping it actually increases in pressure when I accelerate it. I wasn't really sure what to make of the number so I drove it around and got it good and warm and tried again. This time it started at 42-44 psi idling and then dropped down to around 35psi idling. And when I accelerated it once again increased in pressure to around 55-60 psi.

So what is going on here? Was the info about it dropping pressure incorrect? Or is my fuel pump about to say goodbye? I bought a telescoping mirror, and next time it is lighter I am going to try to search for the leak, possibly it will be around the weep hole on the pump.

Sorry it is so long I wanted to give as much background info as possible.

Thanks in advance,

Nick

purpleheart350 · Feb 26, 2012

Fuel pressure can be anywhere from 40-65 psi. When I accelerate my pressure will go up as well, depending on how hard I get in to it. So I think you are ok with you fuel pressure, as far as your fuel bowl goes... It could either be a cracked fuel bowl, lid not on right or oring not sitting right, or you have a leaking line between pump and bowl. It wouldn't hurt to see if the pump itself is leaking either.

Sorry I couldn't help you narrow it down better but at least you know you fuel pressure is ok.

davey99ps · Feb 26, 2012

I could be wrong, but I think the reason your pressure goes up while accelerating is because its a mechanical pump. Therefore the faster the cam spins, the faster the pump turns, unlike the sd that has an electric pump.

94.5stroker · Feb 26, 2012

davey99ps said:
I could be wrong, but I think the reason your pressure goes up while accelerating is because its a mechanical pump. Therefore the faster the cam spins, the faster the pump turns, unlike the sd that has an electric pump.

That's what I was thinking when I read that it should drop....... I can't remember for sure but I think I even read that in a couple places so idk......

I still don't understand why my pressure was 44 the first time and was 44 the second time for a little bit then dropped down to 30-35ish...... I wonder if maybe it is just an intermittent thing idk...... sure is frustrating though.

davey99ps · Feb 26, 2012

94.5stroker said:
That's what I was thinking when I read that it should drop....... I can't remember for sure but I think I even read that in a couple places so idk......

I still don't understand why my pressure was 44 the first time and was 44 the second time for a little bit then dropped down to 30-35ish...... I wonder if maybe it is just an intermittent thing idk...... sure is frustrating though.

Time for a rr an e-fuel.

94.5stroker · Feb 26, 2012

davey99ps said:
Time for a rr an e-fuel.

I'd love to but funds are kinda short right now....... bought to graduate college though so maybe sometime I will have the money....... I am gonna look into building my own kit though idk I just haven't done enough research to decide if I wanna tackle making my own yet...... and the 1000 plus for a prefabbed is too much for me