Fuel Pressure Isolator

[jlwelding]

I am still running a isolator on my fuel pressure gauge and I don't think its reading right. I remember some sort of needle valve, is there a brand or size I should look for ?

[Mopar1973Man]

Ditch the isolator. Install a WH6820 needle valve from NAPA. Warning the price jumped up on them. I would look towards a snubber from ISSPro which is a sintered metal snubber.

[Bullet]

I run diesel straight into the cab with no problems...via snubber and needle valve like Mopar1973Man says.  Gauge has always read perfectly with very little if any water hammer. 

[Mopar1973Man]

I ran the first 10 years with a DiPricol fuel pressure gauge direct plumbed for 10 years. Just a needle valve (NAPA WH6820). Now in my second 10 years of ISSPro EV2 fuel pressure gauge with air brake line from the tap point to the sensor on the fender. Using ISSPro snubber. Looks similar to this.

 

[Haggar]

Sorry I don't like the ISSpro  snubber.  They don't tell you any of the relevant information.  (and the price is a BIT excessive....)

 

Look up Gauge vibration Dampers in McMaster Carr.  Pick one with the smallest orifice size, in the pipe thread you need.

(I took a quick snip of the page from them below.) (I used 1/8 in NPT   0.004".  I did go with the stainless, but I don't know that that is completely necessary.)

I didn't get the filter disc.  I used the plain hole.  I figured if my fuel filtering goofed up that bad, I was going to have to clean more than an orifice.

 

I have an 18" hose from the VP to the snubber to the pressure sensor.  That's it.  ( I have to confess, I use grease gun hose.  Have been for years, but a bunch of womenfolk get their panties in a wad when they hear that.  somehow grease doesn't have lubricating oils in them or something and so they fall apart on the inside like they do on my grease gun all the time...)

 

 

HTH 

 

Hag

Edited April 15, 2019 by Haggar
wive's tail.

[Mopar1973Man]

1 minute ago, Haggar said:

I figured if my fuel filtering goofed up that bad, I was going to have to clean more than an orifice.

 

Not that I would be worried about dirt but how about water and the hole rusting shut? Diesel fuel can have water in the fuel. I'm thinking of more people on the southern state in general here. Where like myself I would also do possibly a small hole damper too. 

[Haggar]

Mike,

 

Unless you have a leak, there is no flow on this line.  I expect that some of my fuel from 5 years ago is in this line.  The only change in that line is due to thermal expansion and pulsing.  I suspect that the pressure sensor moves maybe 0.005" total travel.  That line is stagnant after you do the first bleed.  Most people probably don't bleed the line, so it is probably actually trapped air near the sensor.  This is not a bad thing, just would make the response a tad more spongy, but that is probably never noticed with the damping in the gauge.

 

If rust or solids tried to move down the line, it would stop in the lowest place since there isn't enough flow in the line to be carried by fluid velocity, and most of the contaminants are heavier in density than the diesel, so they don't float up the line.

 

Hag

 

 

 

[Mopar1973Man]

I was just looking at the number of times my system has been dry and the reprimed. The snubber is at the tap point not at the sensor/gauge. So the chances of water being in contact with the snubber is a good chance. This depends if the truck has the factory fuel filter or not. Then if the addon fuel system has a water separator or not. I'll admit even mine has had some water at the AirDog but nothing at the stock filter can. Like my fuel up here is drier than most where biodiesel has more water because of washing the fuel. Then southern states with high humidity have had algae issues which is water in the fuel issue again.

 

Just thinking a wider scope that all.

[Haggar]

That's a great point.  If you install your snubber that close to the vp, it could see flow.  I chose to install it near the sensor, so other than bleeding it will never see flow, only pressure.  So it would be a function of where you installed it.

 

Thanks!

 

Hag

 

 

 

[Dieselfuture]

I think you both have great points and great setups

[jlwelding]

On ‎4‎/‎14‎/‎2019 at 7:50 AM, Mopar1973Man said:

I ran the first 10 years with a DiPricol fuel pressure gauge direct plumbed for 10 years. Just a needle valve (NAPA WH6820). Now in my second 10 years of ISSPro EV2 fuel pressure gauge with air brake line from the tap point to the sensor on the fender. Using ISSPro snubber. Looks similar to this.

 

So this is all I need? I am still running the DiPricol, same as you had.

[Mopar1973Man]

59 minutes ago, jlwelding said:

So this is all I need? I am still running the DiPricol, same as you had.

Needle valve for a shut off then stack the snubber on the valve. You'll be good.