I've had my gauges installed for several months now and they've saved me twice from having a bad lift pump ruin my VP44 but I haven't come up with a way to plumb the fuel pressure gauge to my satisfaction yet. The gauge is plumbed into the VP44 with a banjo bolt with a 1/8" NPT fitting. I originally had it hooked up with a needle valve in-line (barely cracked open) with fuel running all the way to the gauge. This worked great but even with the needle valve barely open the pressure spikes from the VP4 rattled two gauges apart in less than 6 months. Recently I re-did the whole hook up using a fuel pressure isolator from DPP. I was told the isolator would help "cushion" the fuel pressure gauge. Problem with this setup is that the fuel pressure isolator leaks seeping fuel and anti-freeze onto the engine and letting air into the lines. Did I get a rare bad isolator or is this common. Are there any other options to hook a fuel pressure gauge up?

 

Isolators are known to be troublesome. The direct method seems to work best for mechanical gauges. I think you need to relocate your tapped banjo bolt to the filter housing. That should help with the pulsations.

 

You could try something like this that will get your pick up point away from the heavy pulses of the Injection pump.



http://www.genosgarage.com/CoastalDa...D=1575&CATID=1

 

My roommate moved his fuel pressure line to the inlet of the fuel filter. Works a lot better there.

 

I ran mine from the outlet side of the fuel canister so I can tell when the filter needs changed and ran it in between the cowling and the hood so that it sits next to the windshield wiper. No fuel in the cab and I can see it from my seat. Just leave extra line so that you can hook it to the underside of your hood and when you raise it the extra line just flex's with it.

 

Moving the tapped banjo bolt to the output of the lift pump or to the bottom of the fuel canister might help lessen the harshness of the pulsations from the VP44. What is everyone using for a needle valve? I just picked up a rather cheap looking one from a local hardware store.

 

http://www.mcmaster.com/ just type in needle valve in the search box . I bought mine there its carbon steel with viton seals.

 

I bought the fuel line for the dipricol isolator from geno's. I put it on the bottom of the fuel cannister with the tapped banjo, but the banjo and the threaded part of the hose were put into a bing on that engine mount directly below the cannister. I ended up moving it the the VP44 to take it out of the bind. Are these injectors pulses really going to affect my readings?

 

I purchased the needle vavle from NAPA and have it on the back of the gage, perfectly smooth.

 

what does the needle valve do? I just spent all that money on a fuel pressure gauge and isolator, I would hate to have to redo it.

 

If you take your pressure before the filter it will read different and after the filter. I have two under hood gauges cause I tinker with the fittings and lines a lot, one pre and one post filter and there is a difference depending on the condition of the filter. Also I run them direct but I do use a small restrictor that I machine and put in line with the fitting to accomplish the same thing as tne needle valve. My opinion is not to have it right at the VP44 for the reasons stated in previous posts.
Eric

 

Dampens the pulses from the VP44, by allowing you to adjust the flow to the guage so it gets just enough to allow a reading, also a nice steady pressure reading.
Also gives you a quick shut off point, should you spring a leak in a non isolator setup.


phox

 

I got an isolator, and no problems and no pluses, pics in my gallery, and a link in my sig. built a custom bracket for it, and also, the 2 bolts on the bottom where the "L" brackets are were put in from the wrong side, so they never actually bolted the bottonm of the isolator together, I noticed it while installing mine. Might be something to check out.

 

I did notice that two of the bolts faced one way and the other two faced the other way. I didn't give it any thought but if it's only half bolted together that would explain the leaking. I'll give the isolator one more shot before I give up on it.

 

I've got the valve on the output of the filter. So far no problems. I'm coming up on a year now. No leaks, rattle, or failed parts! I love the nice smooth needle swings and quick reactions!

Pics Included - Links in signature... Or Photo Gallery...