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/genosgaragestore/images/d_images/FuelFilterCapWFuelPorts.jpg

http://www.genosgarage.com/CoastalData/showdetl.cfm?&DID=30&Product_ID=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

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.

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 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! :cool:

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

Wes,

Check all 4 screws holding the isolator together, and of course the fitting for fuel in and out. There shouldn't be any leaks if everything is tight.

Mark @ DPPI

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.


In pic all the screws should be going the same direction being only one half of the iso has threads. The bottom screws (looking at the pic in my gallery) were threaded in from the front. I noticed this before I got it running so I dont know if it would have leaked or not. but better safe than sorry.

Your first setup with the needle valve is the best way to go, isolators are a total waste of money.
It sounds like you had the valve open too far.

99 cummins can you explain how you have your gauge held down or mounted?Bolted,clamped or duct taped?
thanks tony3542

99 cummins can you explain how you have your gauge held down or mounted?Bolted,clamped or duct taped?
thanks tony3542
Hey Tony,
Here is the way I have my two gauges set up.

http://www.dieseltruckresource.com/pics/data/500/17270100_0022-med.JPG (http://www.dieseltruckresource.com/pics/data/500/17270100_0022.JPG)
Click on picture for larger view.

Hey Tony I just used about a 4" peice of strapping metal and two short self tapping screws and ran the the bottom side of the hood where it wouldn't go through. real easy to do. I'l see if I can figure out how to put a picture on here, if you don't see it within the next hour or so I wasn't smart enough.

I think the best place to tap into fuel is the bottom of the fuel filter with a tapped banjo bolt. It also lets you keep the test port at the vp-44 to make a verification reading if necessary. I ran a isspro mech. guage with needle valve and ss/braided line. I was getting vibrations even with the needle valve almost closed. I added a 2 foot piece of fuel/hydraulic line to use as a snubber which solved all vibrations. I also was able to re-open up the needle valve.

I added pictures to my photo gallery but they are to small to see very well, if these don't show you what you want let me know and I will PM the larger shots.

From what I have found out ....the VP44 is not the reason that the fuel pressure gauges is getting pounded..The 44 does not push fuel backwards...when you have a lift pump trying to push fuel forwards. Here is the reason that I am saying this..
The fuel pressure gauge that is in my wifes truck would rattle so bad when the needle valve was open too much. But it does not make a sound since I did the FASS system and got rid of the stock lp. The connection to the gauge has not changed and I have not had to mess with the needle valve in a year.
I have had a couple of customers experience the same thing..Its not the 44 killing the gauges...its that stupid lp...

Rick

I agree. You can confirm this for yourself by noticing that the gauge rattle does NOT change with RPM, like it would if it was the VP causing the rattling.

I got rid of my gauge rattle by using two grease gun hoses (18") and a needle valve. ONe GG hose is right at the VP. The other is right at the gauge. The needle valve is plumbed in between the first GG hose and the -6AN line that feeds the gauge.

The presence of the extra GG hose with the needle valve seems to eliminate all rattline. I think the extra restriction (the GG hose has somewhat small orifices) of the second GG hose damps out the vibes.

It helps to have a stronger, industrial-type FP gauge. While my Pyro and Boost are Autometer units, my FP is a Hewitt industrial gauge from Enterprise.

H

You think a Dipricol plumbed into the isolator plumbed to the VP44 will have these "vibration" problems or does that line from the isolator to the VP44 from geno's solve the "vibration" problem?

I turned the two screws facing the wrong way around and put everything back together. Now all four screws are tight and working to hold the two halves together like they should. I haven't had a chance to test it to see if it's leaking yet but just sitting idling there is no air in the lines yet like there was originally. I'll know tommorow if it's fixed or not.

Forgot to add, my gauge readings are about 1-2psi lower than with no isolator. Does this mean there is still air in the lines or is this normal?

How 'bout this...


http://www.geocities.com/rkizzle_homieg/1111111111111.jpg

http://www.turbodieselregister.com/user_gallery/displayimage.php?&photoid=20897&width=0

This is a link to the pic of the back of my Isspro mechanical FP gauge. That little pin-hole is really small and limits the amount of fuel to the guage. I have no rattling or any irregularities with my readings. It is steady and smooth all the time. No needle valve, yet, I will get one for safety reasons. The gauge came this way and is why I highly recommend Isspro fuel gauges. The insert could be removed with only a small screwdriver if it needed to be a different size.

I now have a $5 18" grease gun hose hooked to a standard black boost tubing kit which goes directly to the gauge. Quite cheap.

Edit: By the way, with the Vulcan big line kit, my original lift pump cannot be pulled below 10 psi at WOT. I won't post how little it cost.

Good fuel pressure through a good gauge.
What more can a guy ask for. :D

You are wrong though, the vp does the vibrations. This is what takes the regulator valve out of the lift pumps.

How 'bout this...


http://www.geocities.com/rkizzle_homieg/1111111111111.jpg


That's ok, but how do you monitor it at WOT under load?


phox

That's ok, but how do you monitor it at WOT under load?


phox



I think he's trying to show that one gauge is pre-filter and maxxed out. The other one is post-filter and reads a little lower. Just a guess.

I'm a dummy, so for us dummies how do you get the pictures in there.

Cool Instrumentation Eric!

Well, it still leaks on the fuel side of the isolator. Everything is tight but it appears to be leaking from the large screw used to bleed the fuel side of the system. I'm sick of dealing with it so the isolator is hitting the trash can once I source a new fuel hose and needle valve.

So if the VP44 isn't creating the fuel pressure pulses won't moving the fuel pressure pickup point closer to the LP (i.e., canister) make the pressure spikes seen by the gauge worse?

If its the 44 why is that when I removed the lp and installed the FASS with all that rubber line that my gauge issues stopped! That gauge is as solid as a rock since the FASS install. I am even running a larger line inside the cab to the gauge which would mean a larger volume of fuel pulsations.
The truck is running -6 from the FASS forward to stock fuel filter and then -8 Aeroquip lines to the 44. Fuel pressure is pulled off of a block on the 44 inlet.

Rick

If its the 44 why is that when I removed the lp and installed the FASS with all that rubber line that my gauge issues stopped! That gauge is as solid as a rock since the FASS install. I am even running a larger line inside the cab to the gauge which would mean a larger volume of fuel pulsations.
The truck is running -6 from the FASS forward to stock fuel filter and then -8 Aeroquip lines to the 44. Fuel pressure is pulled off of a block on the 44 inlet.

Rick

You pretty much explained it. Larger lines and rubber. With the same lines mine vibrated as bad with the FASS as before, no difference. The same pulsation, larger lines to absorb more of it. How long has it been on? Give it a couple of months and the vibs start generally. As soon as the air works its way out that is absorbing the vibrations. I used to drain mine and blow it out to stop them.

So it the long and short of it is that one has to either:

1. Live with the isolator if they can get the air out, get it to work, and not leak.

2. Replace the entire fuel system so the gauge won't rattle. Didn't I buy the gauge to keep an eye on the stock fuel system to begin with?

3. Run fuel straight to the gauge and consider the fuel pressure gauge as a "routine maintenance item" just like the lift pump.

I guess the answer to my original question is NO, there is not a "good" way to run a fuel pressure gauge on a STOCK fuel system.

So it the long and short of it is that one has to either:

1. Live with the isolator if they can get the air out, get it to work, and not leak.

2. Replace the entire fuel system so the gauge won't rattle. Didn't I buy the gauge to keep an eye on the stock fuel system to begin with?

3. Run fuel straight to the gauge and consider the fuel pressure gauge as a "routine maintenance item" just like the lift pump.

I guess the answer to my original question is NO, there is not a "good" way to run a fuel pressure gauge on a STOCK fuel system.

It's really not complicated or involved. Run a line from a point past the filter to the gage, put a restriction like a needle valve in the line. Hook it up and like thousands of other systems, it works fine and is trouble free. Until electronics came into it, all big trucks and equipment did it just this way, with fuel pressure oil pressure even water pressure on some. It's no big deal.

It's really not complicated or involved. Run a line from a point past the filter to the gage, put a restriction like a needle valve in the line. Hook it up and like thousands of other systems, it works fine and is trouble free. Until electronics came into it, all big trucks and equipment did it just this way, with fuel pressure oil pressure even water pressure on some. It's no big deal.

I had it setup originaly with a rubber line from the VP44 to a hardware store needle valve (barely open) and plastic tubing from the needle valve to the guage. Even with the rubber line and needle vavle I am on my sencond gauge in 15,000 miles and this one is rattling.

I'm going to try moving the fuel pressure pick-up point to the bottom of the fuel filter canister and I'm also going to order a quality needle valve. Hopefully that will keep the next fuel pressure gauge alive longer.

I had it setup originaly with a rubber line from the VP44 to a hardware store needle valve (barely open) and plastic tubing from the needle valve to the guage. Even with the rubber line and needle vavle I am on my sencond gauge in 15,000 miles and this one is rattling.

I'm going to try moving the fuel pressure pick-up point to the bottom of the fuel filter canister and I'm also going to order a quality needle valve. Hopefully that will keep the next fuel pressure gauge alive longer.

I have an Isspro gage and half of its life it rattled. Still going strong. But it is fairly new, only been on for about 200,000 miles.

The best needle valve is the NAPA deal, I don't have the number, but it is on one of the threads about the gages.

possibly try a pressure snubber through McMaster or the like instead of a needle valve. used one for my boost gauge and it worked great...never did try the fuel gauge (since i didnt need to) but i'd bet it would work. clean install as well. just throwing out another idea that i didnt see mentioned...

possibly try a pressure snubber through McMaster or the like instead of a needle valve. used one for my boost gauge and it worked great...never did try the fuel gauge (since i didnt need to) but i'd bet it would work. clean install as well. just throwing out another idea that i didnt see mentioned...

I'm one ahead of you. I ordered a snubber and valve from McMaster earlier.

That's ok, but how do you monitor it at WOT under load?


phox

To the left of those gauges is the sender for my in cab gauge. I tinker with the fittings an lines a lot for the systems I sell so I like having the gauges under hood as well.

The two gauges I have now don't bounce around and the one I had before did not either. I use small resrictors I made and I loop the rubber lines around to kind of buffer the pulses and my fuel line is all rubber from front of tank to the VP.

I re-installed the fuel pressure gauge system using a pressure snubber at the VP 44 and a rubber line to a needle valve, from there it's plastic tubing to the gauge. No more leaks and no rattling gauge but the pressure snubber really takes away from the "responsiveness" of the pressure gauge readings. To better relate, it's like the gauge is filled with molasses now. It works, it doesn't rattle, and it doesn't leak so I'm now happy.

I re-installed the fuel pressure gauge system using a pressure snubber at the VP 44 and a rubber line to a needle valve, from there it's plastic tubing to the gauge. No more leaks and no rattling gauge but the pressure snubber really takes away from the "responsiveness" of the pressure gauge readings. To better relate, it's like the gauge is filled with molasses now. It works, it doesn't rattle, and it doesn't leak so I'm now happy.

It would be nice if you could share that part number and maybe help someone else out.

It would be nice if you could share that part number and maybe help someone else out.

If your looking for the snubber go to McMaster Carr and do a search and you'll find it.

They have several different orifice sizes available at Mcmaster-Carr if I remember right. Which would you guys suggest to people?

my issopro fuel pressure guage is leaking around the thread to the guage, what can I use to stop it?? i know i can't use teflon tape but is there a tape I could use so its not eat'n up by the diesel fuel[eyecrazy] ?? thx

Permatex Number 2 or liquid teflon paste (Loctite) PST. In both cases make sure you clean the threads well (electronic parts cleaner will work)

Permatex Number 2 or liquid teflon paste (Loctite) PST. In both cases make sure you clean the threads well (electronic parts cleaner will work)

thanx Mr.E ...i mean Dr.E

my issopro fuel pressure guage is leaking around the thread to the guage, what can I use to stop it?? i know i can't use teflon tape but is there a tape I could use so its not eat'n up by the diesel fuel[eyecrazy] ?? thx


You can use teflon tape, but it has to be the "yellow" fuel rated tape.

You can use teflon tape, but it has to be the "yellow" fuel rated tape.

You can but if you ever got even the smallest chunk of teflon in yoiur injector pump...when I would think it would be a big expense

You can use teflon tape, but it has to be the "yellow" fuel rated tape.Sure you can and it will be fine until you have to take something apart and can't get the tape debris out of female fittings without taking everything apart.
Teflon tape is for plumbing, not for vehicles, I don't recall ever seeing tape come stock on any vehical, think maybe there is a reason for this?
Use Permatex #2 or anti-seize for thread seal, easier to find than yellow tape anyway.

Sure you can and it will be fine until you have to take something apart and can't get the tape debris out of female fittings without taking everything apart.
Teflon tape is for plumbing, not for vehicles, I don't recall ever seeing tape come stock on any vehical, think maybe there is a reason for this?
Use Permatex #2 or anti-seize for thread seal, easier to find than yellow tape anyway.


Thanks for the automotive/plumbing lesson. I've used the yellow tape without issue. As we all know, whatever comes stock on a vehicle must be the best solution.... [laugh] Use what makes you feel comfortable!

As we all know, whatever comes stock on a vehicle must be the best solution.... [laugh] Mike, I fully understand where you are coming from but when you consider one of the most important factors in vehicle design is to make sure it doesn't come in for warranty issues you can understand why manufacturers are picky about which materials they use.

As has been mentioned, the Loctite hydraulic thread sealer works well and is not too expensive as a tube lasts forever. Be sure to get the thread cleaner also from Loctite.

It would be nice if you could share that part number and maybe help someone else out.


The snubber is a McMaster-Carr part number 3820K42, the needle valve is a McMaster-Carr part number 4995K42.

It would be nice if you could share that part number and maybe help someone else out.


Also at NAPA... Wheather Head - PN# WH6820

More info in my photo gallery... In the description...
http://www.dieseltruckresource.com/pics/showphoto.php?photo=9753&password=&sort=1&cat=500&page=2