I am planning on buying an Isspro EV fuel pressure gauge to match my other Isspro EV pyro, EV Turbo Bost, EV Trans Temp, and EV tach. When I went to the website, I see they offer a 30 psi, and also a 60 psi unit. I am assuming the 30 psi unit is the one I want, but I have never had to troubleshoot the fuel system on my trck and am totally unfamiliar with what the fuel pressure is between the lift pump and the injector pump. I did a search on fuel pressure, but I can't find those specs. I did see that the pressure at the injectors are around 8,000 psi. .......As Frank Barone would say "Holy C##P!!!!!" I had no idea it was that much. Anybody know what the normal fuel pressure should be between the lift pump and injector pump?

 

When a stock diaphram pump on a first gen is brand new it will make about 7PSI at idle and drop to about 5 or 4 PSI under a load depending on how much power your making.
If you update to the piston pump for a first gen they make about 15 PSI. you should not run much more than that with our VE pumps.
0-30 is the right gauge.

 

Thanks Frostie for the quick answer. I thought the 30 psi gauge was the one I needed. I have a new lift pump(about 7,000 miles on it now). I am assuming it is the stock type. I went to NAPA and told them what I needed, and they didn't tell me there was any option for a piston pump. What is the piston pump? Is that for a newer year model(2nd gen), or it just a high perfomance model for the first gen? Is there any benefit to having the piston pump and the addtl pressure(15 psi)?

 

I see them on eBay all the time. That's where I got mine. I believe the only benefit is if you need more fuel for bigger injectors. A piston pump might let it run longer with a clogged fuel filter. Other than that, dunno.

 

I'd suggest a Westach electric fuel pressure gauge if you want a permanent FPG. Mechanical FPG's won't last too long, even snubbed. Plus Isspro FPG's aren't very reliable. Just my experience.

 

I'm past a year on my $10 mechanical "water" pressure gauge.

 

I have a Westach 16psi gauge, and it works great. Have it mounted where the ash tray once was. I see 7.5 at idle and cruise. I can suck it down to 0 in 4th & 5th at higher RPMs (60+ in 4th 80+ in 5th) and load (30+ psi boost). I think I'll see what she does after the injector pump rebuild, and maybe get a piston LP if I still have issues. I would not recommend less than 4-5psi for very long.

The piston LP is a low flow design, for some 4B P-pumped industrial engines, and some 6B VE'd engines. Or so I've been told. I know CaseIH 4391T power units have a piston lift pump.

Daniel

 

Daniel, don't waste money on the piston lift pump. For a little more than Cummins wants for the parts to do the piston pump, you can tack a Walbro onto the stock system. I could drag my piston pump down to 5 psi but I can't get the Walbro under 15.

 

How much is a walbro 391 or 392 pump? Where can you buy them?

 

I got most of the pieces to put my system together from Glacier Diesel Power.

http://www.glacierdieselpower.com/

Here's the thread I posted about installing it, feel free to post any further questions on there so we don't hijack Scott's thread any further.

https://www.dieseltruckresource.com/...d.php?t=120066