Jay123

https://www.dieseltruckresource.com/forums/2nd-gen-dodge-ram-no-drivetrain-90/getting-air-fuel-return-line-295450/page3/

So there is the history of tiny bubbles from a very hard working ambitious cummins owner, I have the same problem but he never told is what the final fix was.
No high pressure at injectors. So did he change the vp lime so many before him only to find out it was not the problem, this guy was so on it and I know he fixed it because he has posted in 2014 with same truck needing "another" vp. Thanks guys, If you have bubbles please check the link for history.

KATOOM

First off..... Explain what year truck this is, what you've done to the truck, and ANY and ALL reasons or problems you're facing. All I know at this point is you "think" you have tiny bubbles in the fuel. First off, the only way possible to know this is if you have a clear line section so you're visually witnessing those tiny bubbles. Otherwise you're just guessing at what you think is the problem. Have you checked for any codes too?

Explain whats going on with your truck in detail.

Jay123

I get it Katoom.
I could never so accurately reproduce the 3 page thread that covered the all that info.

Lary Ellis (Top)

This is why you NEVER have multiple threads on a problem...it confuses people as they only get half the story unless they get lucky enough to see BOTH threads.

KATOOM

Jay, I'm seriously trying to help you.....and help you get help from others too. But I've been around these diesel forums for around ten years and generally people have no interest to poke and prod someone for accurate info. Diagnosing a vehicles problems can be difficult enough while standing in front of it but.....trying to diagnose through computer screens and peoples ability to explain whats going on can sometimes prove to be impossible. We can talk all day long about the problems on that other forum and what that guys having trouble with but it may have nothing in relation to what your truck needs.

So if you want to fix "your" truck then simply explain whats going on.

Jay123

I installed the new vp. Truck runs better than it ever did, no smoke unless it's from the tires when I step on it. All the bubbles meant nothing.
I am looking for a cheap option to watch the LP pressure, $90 for a light seems too steep. Any ideas.?

KATOOM

Stay away from the low pressure light. The light will tell you only two things, if the pressure is above 5 psi or not and thats not enough information. Gauges will be the only thing which can tell you what the idle, cruising, and WOT pressures are and those are what you need to know all the time to assure you wont have to replace that VP very soon or at all. Fuel pressures should be between 15-20 psi at all times.

Jay123

This fuel gauge is measuring off the high pressure side I presume since the LP supposedly runs at 4psi is what I was lead to believe.
Is it?
OR
Does the LP hit 15 as well?
Thanks

Jay123

Is there a specific gauge "set" you recommend. Should there be one for low pressure side and one for high pressure side?

KATOOM

I will ALWAYS recommend quality gauges as relying on cheap inexpensive garbage will give you just that.....cheap and inexpensive results. Gauges are to be trusted, not hope they're reading correct.

ISSPRO, Autometer, Dakoto Digital, and Westach are all good gauges. There may be one or two I missed.....

There are electric gauges which use a sender or there's mechanical which run fuel to the gauge. Since running fuel into the cab is technically illegal, mechanical gauges will use an isolator which is like a sender but not electrical.

How you connect the FP gauge is by tapping into the supply side fuel line somewhere after the fuel filter. Generally that location is the outlet fitting on the filter housing outlet line. Then you run a small "T" fuel line to the sender or the isolator which then runs wires or isolator line through the fire wall to the gauge. I'm being very non-specific because everyone has their own way of setting this up.

All you really need to be specific about is using a snubber in the gauge line and keeping the "T" as far from the VP as possible but remaining on the post side of the filter. This is because the VP sends very strong hydrodynamic fluid pulses back up through the supply fuel line and those pulses will destroy senders and gauges over time.

There is only one pressure side of the supply fuel pump system. We cant measure the pressure within the VP injection pump as its too high and thousands of psi. The OEM fuel lift pumps are terribly inadequate and are notorious for failure. Over the years its been figured out that the VP works best with running fuel pressures between 15-20 psi all the time. The OEM lift pumps generally have a hard time pumping up to 10 psi and also cant hold offer enough volume when the throttle is applied so the pressure quickly drops off. This is very bad for the VP since the VP requires adequate fuel volume and fuel pressure to run properly and remain cool. For this reason people use aftermarket fuel pumps like the FASS or Fuel Boss. Something you may want to think about since you just replaced your VP and I'm sure you dont want to again soon.

Jay123

Schooled. Thanks great info to help round out my knowledge of this fuel system.
I will hopefully apply it before disaster.
There are 2 unused plugs in 1/8 on the top of my fuel filter, looks like an and an out port can be tapped as they are located at different distances from centre.

Jay123

Ok I get everything but snubber.

Jay123

Found it "Note: A Snubber Valve is required when installing a 30 PSI Fuel Pressure Gauge into a 1986-2012 Dodge Ram Cummins. The Snubber Valve regulates, normalizes and eliminates fuel pressure spikes that are present during the initial ignition and startup on the Dodge Cummins Diesel Engine through the use of a regulator. High pressure fuel system spikes during startup are harmful and may cause early and unexpected failure of electronic fuel pressure sensors and/or sending units for fuel pressure gauges.
- See more at: http://www.glowshiftdirect.com/MaxTow-30-PSI-Fuel-Pressure-Gauge.aspx#sthash.WzU17OjY.dpuf"
Glowshift is this any good. Nice looking anyway.

KATOOM

I'd suggest staying away from GS. They look cool and plenty of people have tried them but if you do a simply Google search regarding GS gauges, you'll find there's far too many negative threads about all the inaccuracy and problems.