Why does everyone mess with the schrader valve for FP?

I am reading about setting up a fuel pressure guage, and it seems most people are messing with the VP44 itself, and having problems with it. We just installed a fuel pressure guage in my dad's ram and just drilled and taped the filter bowl top. Worked like a charm, don't understand why people even mess with the VP.

 

Most of the guys I see installing FP setups are doing it on there fuel filter housings. On early 24v motors you can use the post filter test port. On later 24v motors you can use a tapped banjo bolt to use as the test port.

I am going to install mine on the post filter port on the filter housing.

Harley

 

I finally got my Juice after having to pick it up myself at my local UPS distribution center, and in the directions they show hooking the supplied fuel pressuer sensor to the shrader port too, so I guess I spoke too soon.

 

It's simple to hook it up to the VP...........with a hose and the isolator mounted elsewhere. Why wouldn't you?

As to 'why', because some of us want to know exactly what the VP is seeing FP-wise.

Incidentally, does your father have to unhook stuff to change his fuel filter?

 

Agreed.....I don't see what you have to mess with to hook the hose up to the schrader valve test port. It couldn't be any easier. Just remove the valve core and screw on a #4 SAE fitting (45*) or many guys just use the more common 37* -4 JIC fitting....at these low pressures, the difference in flare angles won't cause leaks.

If you happen to have a 98.5 or 99, there are already two 1/8" NPT ports in the filter housing (pre and post filter) that you can use.

This is the way I did it on my 98.5....I have a prefilter gauge on the housing and the hardline connects to the needle valve which in turn connects to braided hose that goes to the gauge.

 

I use tapped banjo bolts (2 each) on the fuel filter housing to measure pre-filter and post-filter fuel pressure using a Westach dual combo gauge (2 gauges in one housing).

Rusty

 

I just remember guys having problems with ruining sensors due to the pulses from the VP44 or something, may be from a different spot, who knows.

I hooked my Juice's sensor up to the schrader port today, wasn't as a PITA as I thought. I stand corrected.

 

That's the reason for the isolator I mentioned. It's from the engine vibration.

 

That is what the needle valve is for - to dampen the damaging pulses to the gauge or sender (in the case of the electric gauge).

 

Like mentioned, that is why guys are using the needle valves to dampen the pulses. You barely open the needle vavle and it will let enough pressure threw to read your FP but it won't let the fuel surges threw enough to hurt your gauge.

I picked up a 1/8" NPT needle valve, 2 female NPT fittings, and some pipe tape from my local Ace Hardware the other day for $12. I got an 18" greasegun hose from Napa for $6. So after the price of the gauge I am only going to have $18 invested and all the parts for the install are cheap and pretty easy to find. The needle valve itself took a little finding. Home Depot didn't have it. But my local Ace did.

Harley

 

A lot of these problems can be eliminated by getting the
Vulcan big line kit. It comes with a threaded "T" that can be installed anywhere. Between the filter and the VP44 is best.
No drilling or taping and a much better fuel flow
vulcanperformance.com

 

The way we installed Bobby's dads sending unit was we drilled and tapped the hole in the middle of the filter cover. This then mounted an electric sending unit that is simply disconnected by a snap in connector and then a deep socket can be used to remove the cover assy. It was a relatively simple way to install the sending unit with mininmal extra parts needed and zero leaks.