So i bought the gauge with the gauge kit and am getting ready to hook it up, Do i need to use the pressure gauge isolator shown in the pics? and if so what does it do? also i have a schrader valve coming off of my vp44 can i plumb the gauge in there?

Well that depends. How comfortable are you with fuel going directly to the gauge in the cab? Some people are very against setting up their fuel pressure gauge that way in case there's a leak, whereby you could have a lot of fuel pumping in the cab until you have the opportunity to shut the engine off. Then there's the people who have it setup that way and are happy.Electric gauges are so popular because you dont have that variable. The problem with electric is they can be unreliable and potentially inaccurate because of the dynamic fuel pulses from the VP and how corrosive ULSD is to the senders.The fuel isolator is not hard to install and removes the fear of fuel in the cab. It just takes a couple more steps in the installation process.

I guess im not opposed to fuel in the cab lol, ill have too see how i feel when i hook it up i suppose.

Most don't use an isolator. One draw back with an isolator is that it can gice you a false reading depending on the diaphram not being properly positioned at the start of the install. Regardless, you are putting a gauge on your truck and that is a smart thing to do!

I have a mechanical gauge install in the cab with no isolator. I prefer it that way. It is installled in a 3 gauge pod on the A pillar. I use a needle valve installed into the fuel line as an isolater, and it is barely cracked open for the gaguge to read the pressure. Like Katoom says, it is a personal prefrence. The needle valve does give me the option of turning the fuel oof to the gauge if a leak starts. I also have drilled a small hole in the pod for the gauge in case it does start leaking. This allows me to see it before I have to smell it leaking into the carpet and behind the dash. Pure mechanical is better in my opinion, but fuel in the cab is a personal choice.

Here's another tip.....I ran an electric fuel pressure gauge for years and I liked it, that is until the sender failed. For multiple reasons not related to this topic, instead of replacing exactly what I had, I chose to go mechanical but I was afraid of fuel in the cab so I used an isolator.I always research something to the level of neurotic obsession, so I feel the isolator is the right choice for me. But my point is..... No matter what gauge brand or type anyone uses, I highly suggest plumbing in a test port to have the option of comparing your gauge against another gauge without tearing everything apart. So many times I read of guys confused by their gauge readings or wonder if what the gauge is telling them is right, but obviously they have no way to confirm anything since the only way would be to remove the gauge. Really guys, that's not being proactive at all. I say that sheepishly because I was in the same boat too when my electric gauge started acting up. So knowing from experience, when I changed to a mechanical gauge, I simply purchased a cheap T fitting, plumbed it in just before the isolator, and placed one of the original OEM schrader test valves in the T. This way I can hook up a test gauge and know whether my gauge is telling the truth. Matter of fact, just because I'm me, I tested my current gauge against a test gauge and the two gauges were within about 1 lb of each other. I was happy with that.Here's a picture of the T and the schrader valve pointing up. Its brass and really the only thing in focus in the picture.

I tapped my gauge into a tee in the big line kit I installed a while back and capped the outlet on the 90* fitting so I can bleed the low pressure side easily and connect a test gauge to it also. It works well.

Just installed a ISSPro today in a 2002 Dodge Cummins with a stock fuel system...ISSPro Fuel Pressure Gauge, 1/8" Air Brake Line (rated at 600-800 PSI), WH6820 Needle Valve, Compression Fittings (Male and Female), and Tapped Banjo Bolt

Edited February 11, 20223 yr by Mopar1973Man

Your truck Moparman?

Nope... A friend on the local fire Dept. I stopped in to check out a performance problem and found a P0216 code. So doing the next step we installed a fuel pressure gauge and so far he's got 15 at Idle not bad but I didn't drive it. So He'll report back his finding by next fire meeting.Katoom you must of not seen the tapped banjo bolt?

Oh I did..... And I also saw '02 Dodge in the post, and you have an '02 Dodge so I was confused since I couldn't imagine you were changing things up on your truck. I was going to have to question your logic.

Oh I did..... And I also saw '02 Dodge in the post, and you have an '02 Dodge so I was confused since I couldn't imagine you were changing things up on your truck. I was going to have to question your logic.

Please do... If I'm dumb enough to re-install my stock 6mm lines and banjo bolts please beat me with a stick.

Some one should sell these kits pre-made and ready to bolt onto the truck.

Some one should sell these kits pre-made and ready to bolt onto the truck.

The only reason why not is because it doesn't have the isolator and its not desired by the gauge manufacture either. Also it really couldn't be pre-made because of the location of the tap point. It might be all the way under the truck at the AirDog / Raptor or it might be in this case at the stock fuel filter. But get the bit and pieces isn't bad it just most gauge dealer shove the isolator in the kit too.

I "think" the reason you see an isolator comes with all mechanical fuel pressure gauge kits is because its not legal for them to sell a kit which plumbs fuel directly into the cab. I may be wrong but I remember hearing that before.

I bought a stainless steel case,oil filled 2 inch guage with 1+- psi accuracy 0-30 guage from a hydraulic supply. 1/8 npt back port.($35.00) I mounted it on the floor just left of the center consol near the accelerator pedal. Drilled hole in floor,1/8in conn,1/8X1/4 compression 90deg elbow, 1/4in air brake quality tubeing and fitting to the vp44 inlet banjo. Lots of room under floor to work. Hi quality and quick to install. On the floor but how often do you need to ck fuel pressure.

I have had a mechanical in the dash for 10 years now with no issues. I run a stainless braided line from the bottom of the fuel filter canister directly to the guage. Have a small needle valve just slightly cracked opened working as an dampener. It also is my insurance to remove the fuel from the cab in case of a leak.Do it right and there won't be any issues with leaks or problems. Mechanical gage setups will better take the pulse abuse of the VP than an electrical.Jeff

So i bought the gauge with the gauge kit and am getting ready to hook it up, Do i need to use the pressure gauge isolator shown in the pics? and if so what does it do? also i have a schrader valve coming off of my vp44 can i plumb the gauge in there?

THEGOLDPRO, do you happen to remember where you purchased your isolator? I have the same exact one but.....cant seem to remember myself and am curious about replacement parts. Thanks.

THEGOLDPRO, do you happen to remember where you purchased your isolator? I have the same exact one but.....cant seem to remember myself and am curious about replacement parts. Thanks.

thats a vulcan kit....bought the same kit a week ago

thats a vulcan kit....bought the same kit a week ago

Thanks KY. It seems we're all visiting the same few good Cummins forums. Also, Geno's has the same kit, which they probably get from Vulcan.

Thanks KY. It seems we're all visiting the same few good Cummins forums. Also, Geno's has the same kit, which they probably get from Vulcan.

glad to help.... it came with 1/8 line and im gonna swap it with 1/4 soon as i find the right fittings... i went ahead and mocked it up tonight and when i first started it up...i read 11 psi at idle... then it bled down to zero....while it was running...??? dont know why, but i thought maybe some air still in it....sooo bled the guage line again and got all the air out..put it back together fired it up....reading 5psi at idle..WTH?? not really sure but im gonna upgrade to the bigger line and also pick up a test gauge so i can compare