I ordered the Dipricol gauges the other day for the truck.The fuel pressure gauge says it comes with a mechanical isolater.But I dont really know how to hook the gauge up.I have heard of using the schrader valve and tapped banjo's.How should I go about doing this.Does the gauge not come with everything you need for installation?It sounds to me like the npt fitting is not the right size,so you have to buy or make a hose for it to fit to the schrader valve.I am having my brother help me(former pro mechanic)so I bet we can figger it out.But he didn't work on diesels so any info would be great.Also,were on the vp is the schrader valve?

 

To find the schrader valve, just follow the fuel line from the bottom (outlet) of your fuel filter housing towards the front of your truck to the VP44. You'll see it protrude from the banjo bolt on the VP44.

gud luk,

Casey

 

Do I need to get the little hose that has the npt fittings on each end?And thats it?And what is a needle valve?Is it the same as a schrader valve?

 

If you use the isolator, you don't really need the needle valve. If you send raw fuel into the cab, to the gauge, it's better to have a way to shut it off. So the valve comes into play. With the isolator you don't have fuel in the cab at all.

 

The Schrader valve uses the same geometry as the old R-12 AC refrigerant hoses. Find an old R-12 AC service hose and it screws right on.

 

So,all I need to do is get the hose and connect it to the schrader valve and then to the isolater?And with the isolater is there going to be a fuel line running to the gauge itself or is it going to send a signal for the gauge to read?These are Dipricols.Thanks for the help,I'm kinda confused.

 

On the gage side of your isolator, you need to fill it with antifreeze. Read over the instructions for the isolator again, I believe it says something about using a dull instrument to push the dimple toward the fuel side (?). Then fill it with the antifreeze and screw the tubing onto it and the gage. I also mounted the isolator right by the hinge for the hood, Made a bracket and set it up that way. Now the engine vibration is isolated from the isolator so to speak. I can maybe take a picture of it tomorrow, would that help?

 

There is a separate line from the isolator to the gauge. This line also has liquid in it, but not fuel. The whole point of the isolator is to keep the fuel out of the cab for safety.
So, line from the Schrader valve to the isolator has diesel in it. The diaphram in the isolator allows the pressure to transfer from the fuel side to the safe side. The safe side runs into the cab and attaches to the gauge. So, even if you have a leak it isn't as dangerous... fuel stays in the engine compartment and if the leak is in the cab, it's a safe liquid.

 

OK,so there is not going to be any fuel in the cab?That is what I was wondering.I just need to figure out what hose to run from the schrader to the isolater.The schrader is 1/8 I believe and the isolater side of the hose is 1/4 for some reason???Aren't most of them 1/8 as well?Thanks so much for the help,not as confused now.I dont even have the gauge yet so I havent read the instructions.Probally would help.Just trying to figure it out before hand.Thanks again.

 

Also,what about vibration?I have heard alot about this messing up the reading.Is why you mounted the isolater away from the engine Mtn. Camper?

 

Yes, Exactly, I just did the install today with a very good friend, who happens to be an excellent mechanic. He has done a few of these and has never had a problem. Works for me. Tomorrow I'm off to Napa, to get the adapter to go from the Schroeder valve to my tubing. All lines are run, isolator is mounted, and the gage is in place. But we didn't have a nut to fit the valve.

 

I think its a better idea to use a tapped banjo on the bottom of the fuel filter and leave the schrader valve free as a secondary test port.

 

Done a little rethinking, after Dr. Evil's post, decided to order a Banjo Bolt from Jeno's. Should work fine. I should be able to just replace the one at the VP44, correct? It's easier to get at than the one under the filter.

 

I've done the prefilter method, on the front of the fuel filter housing, and more recently after a FASS II install the post filter, underneath the fuel filter housing. I prefer the post filter method as you can gauge the flow through the filter. I'd leave the schrader valve as is secondary test port as in the Dr's advice previously. But the cool thing is, its your truck and you can do whatever the **EDIT** you want. .


Have fun.

Casey

 

I like using the one under the filter, that way I can connect another gauge at the vp44 to compare the readings.