fuel pressure for 12V?

gstanfield

gstanfield

Are we there yet?
Joined
Jun 27, 2006
Messages
777
I'm wanting to add more guages to my truck and thought I'd throw in a fuel pressure guage so I'd know when the overflow valve goes bad. What pressure is the 12V supposed to be running? Also, where would be a good place to feed a pressure guage off the P7100?

Thanks,
George
 
I'm not completely sure what pressures are "normal".. I've been told 22 or so at idle and 17-18 at 2500 free-rev..

Mine however, runs about 38 at idle and will hold 42 at 75-80 mph.. :rockwoot:

Alot of guys tap the supply banjo bolt on the side of pump and put the line there.. I chose the easy route and removed the bleed plug on top of the filter housing and put my valve in there, then ran the line off that to the guage.. Let me know if you want some pics.. got the head off right now so should have a clear shot..

Brad
 
Well, the 8 seems extrememly low to me. I had a 887 truck that got to 9psi and we had bad rack float. I don't know if that is normal for that psi but it was a major problem as it was falling flat on its face over 2500 rpms. I have always been told 25 idle, 15 WOT are good number to go by.
 
wildmanben said:
yeah I know, Still trying to figure what to do about that....
Click to expand...
Join the crowd, auxillary fuel pump though the mechanical pump is awesome at one point it just can't keep up.
 
ok..... i checked my fuel pressure at the line coming out of the filter housing to the pump. and i had around 40 at idle and about 15 at WOT.

But, is there a pressure difference betweent the two different spots (side of pump and filter housing) ?
Cuz i am hearing people with 40 something psi and some people with 20 psi. Why is there soo much of a difference?

Lance
 
the only different thing different that i have done to mine is stretch the spring in the overflow valve. Would that make the difference??

If not then what is the deal?

lance
 
stretching it will give you some more pressure but its only for a little bit. did it to a buddies truck and he saw 45 at idle.
 
oldsmokey97 said:
ok..... i checked my fuel pressure at the line coming out of the filter housing to the pump. and i had around 40 at idle and about 15 at WOT.

But, is there a pressure difference betweent the two different spots (side of pump and filter housing) ?
Cuz i am hearing people with 40 something psi and some people with 20 psi. Why is there soo much of a difference?

Lance
Click to expand...

There shouldn't be any difference.. Pressure at the top of the filter housing will be the same as pressure at the banjo bolt..
WOT no matter what RPM mine would not go below 30.. We'll see if it's the same when it's back together, but it should be as nothing with the inlet fuel system has changed.
All from the mechanical LP on the block...
 
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then why is my fuel pressure so much greater than wildmanbens??

i guess the stretching of the spring did make that much of a difference.

Lance
 
I would guess.. I stretched mine as well.. Maybe a bit more than I should of from the sounds of it, cause mine's higher than both of yours..
 
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