Seems every gauge seller warns you to always use an isolator, but I've heard you get better readings not using an isolator. I like the diPricol gauge but every advertisement has that stinking warning (liability maybe?).

So is the tube breaking and spraying diesel into the cab such a remote chance I've no need to worry? I'd like to just find a long enough SS braided line to snake it up to the pods and just attach a 90 at the fuel filter and be done with it.

 

I just bought gauges, bought the isolator. Going to take a reading reading with and without the isolator. Don't like the possibility of having diesel fuel being sprayed into my cab. Even though its a slight chance, my luck....

 

Most people don't like the isolator because they seem to go bad after time because the diesel eats them, thereby causing them to replace them. Some people have had good luck with isolators. Not sure if one brand is better than the other.
I had rubber fuel line run into the cab of my truck instead of braided SS. I used the same setup that member Moose10 did.
Check out his pics here: Click This
If you look through his pics, there are some excellent ones of the parts needed to run the fuel line up to the cab. This includes a needle valve to isolate the gauge from the high pressure pulses of the VP44, which can also be used as an emergency cutoff valve. There are also pics of the connections at the lift pump. I used the pushlocks and hoseclamps as shown and have no issues with leaks.
Yours is a '99, so your setup at the lift pump will look a little different, you have test ports on the top of the fuel canister to which you can hook up a gauge to rather easily. See Rattlinram's picture gallery.

~Rob

 

In the past 4 years I have used both the isolators and non-isolator connections to the fp gauge inside the cab. I also have used products from SS braided line to Areoquip rubber line to my current choice which is fuel grade boost size line with a needle valve under the hood. There has been only 1 truck that I have mounted the fuel pressure gauge in the A-pillar and it was plumb'd with the SS line. It has been over 2 years and its still doing fine. All the other trucks the fp gauge is installed in a single pod below the dash,just above the edge of the tunnel. The gauge can been seen easy by the driver but also of any leaks does develope you wont have fuel running down the A-pillar into the fuel panel.
Do you need an isolator..that is a call for the owner/installer. All the customers that I have delt with have no problems with this once I explain my procedure for the installation. There are 2 reasons for the isolator IMHO, first is that is isolates the gauge from the pulsation of the lp(with the FASS or AirDog you wont have) and second is that you keep live fuel out of the cab.
The above 2 reasons is why I do install a needle valve inline. The needle valve buffers the pulse of the pump and also its a way to shut the fuel off if a leak developes inside the cab. But it comes down to who writes the check as to what is the best in their world.

hotdram...
For a long time I though as you that the VP44 was pulsing the gauge..but I do believe I have change my mind. Once I put the fass system on my wifes truck.. the pulsing went away. The gauge connect did not change! I had problems with the gauge up until I added the fass and they went away. The stock lp is a rotary type which causes a pulse. I am not sure if the FASS system pushes the fuel thru the filters or draws it from the filters but it does not pulse the gauge..


Rick

 

I would venture to say that after a few years 90% of the isolators in use have failed and the owner is none the wiser. The diaphragm in the isolator gets a crack in it and allows diesel to the gauge. They just can't stand up to the pulsations a diesel engine produces. If you have the choice not to get one with your gauge save yourself some money as the isolator often costs more than the gauge.

 

I run high and low pressure isolators in my Jeep and have done so for years without a failure or a leaking diaphram in the isolators.......I run them in the Jeep because it operates in a harsh and competitive enviroment and I don't want to run the risk of gasoline leaking into the driver compartment - no matter what....some sanctioning bodies require them.

That said, I see no need for them on a CTD.....a FP gauge properly plumbed with good quality hose and fittings shouldn't have a problem ever with failures or leaks.......and the worst case is if it does leak, diesel is MUCH less dangerous than gasoline..... the needle valve arrangement can still be used on the fuel side of the isolator to dampen spikes to protect the diaphram if that is what is desired.

 

I decided to skip the isolator and install an electric fuel pressure gauge. The only thing going through my firewall is an electrical harness, no muss no fuss. Also, if you go this route you will need to remotely mount the transducer on either the fender or the firewall. The vibratory environment of the engine will eat that sensor for lunch.

 

I have no isolator and no problems. It comes with no surprise that the companies want you to buy an isolator: 1) liability: oh, I got diesel fuel smell in my truck! - We are not responsible, we sold you the isolator, and 2) the gauge = $30, the isolator = $180. Very simple.
To me - fuel pressure is very low. Any decent hose can hold 15-20 psi, and of course a 3,000 psi steel braided hose is a nice investment
-P

 

i used a copper line, fittings fit well and deff strong enoff for the pressure, thinking about cutting that out and hooking a ruber hose to it just cuz that copper line is a pain. the worst thing that can really happen is a little fuel leak, if u smell diesel in your truck just check the line. diesels not as flamible so fire risk is very minimal, if i was doing this for a gas or alcohal motor i deff would invest in the isolator though.

 

Almost 5 years now with the the same piece of SS teflon line with NO isolator and no problems. Nuff said

 

One issue not mentioned: Does your state require that no fuel line be run inside the passenger compartment?

Second, why not do as all the hot rodders do; place the fuel pressure guage on the cowl outside the windshield.

 

I think that's the reason no one (AFAIK) sells the gauge without an isolator. Eric @ Vulcan has told me it is not legal to allow fuel into the passenger compartment.

 

If you don't want to use an isolator, then just use SS braided line with AN fittings. Unless ur a , it's pretty hard to make it leak. I used -4 line with AN fittings inside the cab and put a needle valve out on the pump to shut it off if there would happen to be a problem.

 

My isolator leaked and made my VP swallow a bunch of coolant (it was filled with glycol). It wasn't isolating anything!

Ditched and went direct and haven't had a problem, nor have I looked back.

Save yourself the hassle.

JMO

 

I was using an isolator. After a couple months of putting it on it went from showing 21psi at idle and slowly dropped until it only showed 5psi at idle. I figured it has to be the isolator since I just put the FASS on it a little while ago. Took it off and it shows a little over 21psi all the time now and now less than 15-16psi at WOT.

IMO, ditch the isolator. Not like it won't be obvious if there is diesel in the cab...A lot of people run no isolators for years with no problems what so ever.