93-12Smoke

Installed my new Isspro fuel pressure gauge today and found out my 2 year old lp is making a whopping 4psi at idle and pulls down to about 1psi at 1/4 throttle.. Guess I'll be spending more money now!

Would just injectors cause that low of a fp reading?

thrashingcows

Think those number are about right for a diaphragm lift pump. Go to the low flow piston lift pump. Can't recall the flow numbers but I know it was way better then the stock diaphragm units

93-12Smoke

Thinking maybe air dog or fass.....

j_martin

The VE pump just needs to be able to fill to run. Theoretically anything from 0 to about 10 psi will work fine. Also theoretically, it can actually run with a low negative pressure. (no LP, decent low lift fuel feed)

So, if your gauge is off the peg at WOT, you should be fine. More pressure won't deliver more fuel.

A little more pressure, however, compensates for a marginal fuel filter, cold fuel, etc.

93flatbed

J, although I agree with nearly all of your comments I'm going to have to disagree with you on this one with his truck. In stock form I kinda sorta agree with your above comment. With more fuel demand from the pump the more it likes higher pressures and flow, it returns what it doesn't need. I've spent several hours with different inlet pressure settings and found what works best for the pump I'm running now, being more than "what is accepted" by the general 1st gen crowd.

Lots of factors play a role in inlet pressures, but for his pump and injectors I'd suspect that 12 psi would be a good starting point. I'd also like to add that having an electric pump that you can turn the pressure up on is kinda nice. Or if you want to stick with mechanical then a belt driven pump or a second gen pump with a return regulator would be good. I've never ran a mechanical set up like that just what I've read and seen. I was going to go with a belt driven set up until I came across a deal I couldn't pass up on my 165. But note that I'm still wanting to do a belt drive pump if I come across something then I will put the 165 on the crew cab.

dieselJon

Look up the Hungry Diesel. He has P-pump lift pumps (larger barrel diameter) with a low pressure spring. Something like $250 for the whole getup.

Rick 12v CTD

ya hungry diesel is a guy on cf named rccummins. He has a cummins powered Ram charger, hence the name. He seems like a decent guy and knows a good amount of stuff about the first gens

93-12Smoke

Anyone tried the raptor 150? Looks like a good price and not much more than a low pressure lp set up

j_martin

I can see a need for more supply pressure at high flows. 12 PSI might be a bit hard on the seals, though.

93-12Smoke

I've always heard 12-15psi is where you wanted to be and 7psi was the minimum

93flatbed

Green lock tite has held mine into the 30's. There was a guy on 1st.org going by the screen name of ford(and a bunch of numbers) that pushes into the 70's and his problem was the fuel started to leak past the seal on the shaft side. He also stated the vein pump imploded in the high 70's. Brian pushed a huge amount of pressure into his pumps too. I don't think either of them did any work inside the ve for inlet passages either though. I know the ford guy tried to do some vein pump work but it didn't turn out well for that pump, but that was back when guys were trying to rock the 14mm and 4mm cam plate. Which as we know don't work out very well.

Back to the op, I've seen a 150 on a very nice truck that did some big numbers for a 12 mm Giles built pump. Also seen them on common rails. But I have never ran them so I can't give personal advice. I'm still going to tell you to look at the belt driven pumps.