i'm thinking of buying a fuel pressure guage kit and it comes with the isolator. now i've heard people say not to use the isolator because it has failed, but i was told that it is not legal to hook it up without the isolator. soo, the question is, why or why not should i use the isolator? who all out there does, and who doesn't? if i don't use the isolator, i was told, then the fuel goes in the cab, what does this mean as well?

well that's all i got for now
thanks in advance

 

All they mean by fuel in the cab is that you have a line with fuel in it inside the cab, not that there is fuel spewing in the cab. IMO any mechanical fuel or oil pressure gauge should have a shutoff valve on the engine in case of a leak. That is how my mechanical in-cab fuel pressure gauge is set up.

The isolators use a rubber diaphragm with antifreeze on the cab side. Many people have reported that the diaphragms in these have failed, so there was diesel fuel up to the gauge anyway.

The legality issue is one I am not even going to touch.

 

ok that helped explain it a bit more, thank you. but, now here's the other thing. the company whom i was/am gonna buy the kit from said that they can sell it to me without the isolator, and without the isolator it's about $30 cheaper, so should i just save myself the trouble of having it fail and purchase it without the isolator?

 

My understanding is that it's legal for you to run fuel into the cab but in some states it's illegal to sell a fuel pressure gauge without an isolator. Most of this is related to the flammability of gasoline, something that doesn't really concern us.

Besides the diaphragm failing some folks have had problems with air in the antifreeze side of the isolator causing bad readings. Not something you need worry about without an isolator as air in the line will eventually work it's way out. Nowhere for the air to go with an isolator.

$30 is a good price for an isolator, they're usually twice that price.
Your decision.

 

the reason that most isolators fail is that they are installed without a snubber. The snubber reduces the pulses from the vp44. Some people use a needle valve for a snubber. They just barely crack the needle to contain the pulses. I bought a snubber from the place that sold me the gauge kit and it seems to work.

 

Andrew, the simplest setup is to use SS braided hose from a valve on top of the fuel filter; not having an isolator is one less thing to go wrong. It is highly unlikely that the braided hose would fail; more likely something inside the gauge. I have the valve on mine opened up 1/8 turn from closed to eliminate the pulsing and vibration of the needle, and it works great.

 

where can you find the ss braided hose at?

 

Mine came with the gauges, and it's been a few years ago, so I don't remember who I got them from. But if you check around with the various gauge suppliers, I'm sure you could get what you need from them.

 

i got mine from dieselmanor.com. It is sweet! The kit also comes with a banjo bolt.

Bob

 

Good advice but not for an 02 the fuel filter is different. In the interest of complete correctness, on an 01-02 you need to take the fuel off the bottom of the fuel filter housing or at the test port on the VP-44, or at the inlet banjo on the Vp-44. Your choice.

 

Dr. E...it's a good thing you're here to keep us on track!

 

well ya'll, the company i was gonna buy a fuel pressure kit from has been having problems with the isolators so they took them off they're site and are only offering the guage itself now.

so is what i wanna do is install a FP guage on my truck (check signature) and i want a parts list so i know everything i need to do the job and avoid unnessary/unexpected trips to the hardware and/or auto parts store.

so if i could get a parts list or something and have everything for a reasonable price i would appreciate it.

thanks all for the help.

oh and some detailed instructions too.

 

Ridiculous, all you have to do is hit the search button....the info is already here...pages of it.

 

dr. evil, i hit the search button and it led me on to a scavenger hunt that i did not enjoy. i couldn't find what i needed there. i just want a parts list and some instructions. could you help me out ppllleeeeaaaaassseee

 

Sure, I can help you but I dont really believe you couldnt find the info

This is fairly easy...But for the parts, it really depends on what kind of fuel line you want to run. There is a couple of options - regular 1/8" boost line, 1/8" DOT brake line, 1/4" bradied S.S. line, 1/4" hydraulic line.

In the most basic install (on an 01) you will need a tapped banjo bolt, a needle valve, and hose to run into the cab to your guage. Theres no real kits available (at least that I know of) where you can get this stuff. The tapped banjo bolt goes on the outlet side of the fuel filter (on the bottom), the needle valve screw into it, and from there the hose runs to the guage. It parts and install should look something like this:









The blue hose obviously goes to the guage. Thanks to Moose10 for the pics....

You should be able to get most of the fittings and stuff (including the needle valve) from Napa or you can get it from these guys:

http://www.dieselmanor.com/dm_products/dm-products.asp

Alternately, you can install a guage on the VP-44 test port (I wouldnt really recommend that route) or at the inlet of the VP-44 line.

Is that the info you are looking for?....I hope that helps. Happy to answer any more questions.

BTW, the needle valve should be just cracked enough so that you get a smooth reading. You need the needle valve to dampen the pulses from the VP-44 and save your guage from destruction.