dodgeguy71

My fuel pressure gauge has been acting a fool lately. Seems everytime I think I can actually sit back and drive some fuel pressure issue arrises on this truck. Fuel leak, 1/4 tank issue, fuel gauge issue....always something and has been that way since I've owned this truck.

Finally, I think I might have it all worked out. Fuel Boss on the front, been there for a year or so, works great. Replaced my intank pump that was Dodge's cure with the original style pickup and fuel level sensor. Re-worked the hoses that connect my pickup so I can install an original style block mounted electric pump as a backup, priming pump in case I do work on the Fuel Boss.

Next issue, mechanical fuel pressure gauge. Always toying around with the coolant in the line, getting the air out and so on. So with the addition of my Quadzilla a few months ago I picked up a tranducer the other day. Screw it in and plug it up, accurate fuel pressure! Why did I wait so long to do this!? Thinking I'll ditch the isolator but my concern is destroying the fuel pressure gauge. My Diprocal EGT has died recently for some reason so as I tend to keep things for a very long time I don't want to kill a fuel pressure gauge every year or every other year.

What are you guys running that will handle the fuel in the gauge without destroying it? Is there a ready made hose that I can buy that will run from the fuel filter, thru the firewall and up to my dash mounted gauge?

KATOOM

Sorry to hear you've been having troubles but changing any factory design to aftermarket means we're the test Guinean pigs for the aftermarket manufactures.

The transducer you're talking about is what most electric fuel pressure gauges use now because of the additives in diesel fuel they've been using for the past few years are giving fuel pressure senders trouble. So now they all use solid state senders. I'm going through the same trouble right now too with my fuel pressure gauge. I was running a Dakota Digital which recently started reading inaccurately. So I'm now installing an Isspro mechanical fuel pressure gauge with an isolator. Running fuel into the cab just isn't an option for me since running 15-20 psi, it would only take one leak to destroy everything in the dash and cab before I could stop the leak. And after researching, everyone seems to be having great luck with their isolator. The only thing I'm doing different than some is using 1/4" DOT air brake line from the isolator to the gauge instead of 1/8" line. I feel its more reliable from potential damage or kinks and the fittings look like they will seal better since 1/4" compression comes with the internal reinforcement that fits in the line where 1/8" doesn't. As for bleeding out the air in the lines, well the isolator has a bleed screw for purging air out of the fuel side and I understand that trying to purge "all" the air out of the isolator side isn't necessary.

Either way you choose you need to use a snubber or you will eventually destroy any gauge or sender because of the constant dynamic pulses from the VP. Geno's has one that's specific for fuel pressure for only about $10. Its a fitting and not a needle valve and you just put it in line before the sender or isolator.

Shovelhead

I've been using the same Isspro mechanical fuel pressure gauge sitting on my dash, plumbed with stainless braided line (no isolator) and a needle valve from Grainger since 2000 with zero pressure gauge problems.
Many transfer pumps , but still the same gauge setup.

kawi600

I run westach gauges with a remote sender for fuel pressure. Its fine as long as you put a snubber in front of it, and dont run biodiesel.
One of these days im going to take one apart and see if I can repair it.
Another option is to use an isolator so that pops before the sender does.

dodgeguy71

I'll have to check out the snubber. Got the isolator but have not fooled around with it. Been getting the differential back under the pig. Should have some time tomorrow to mess with the gauge side of the fuel pressure line. I'm also not a big fan of the fuel in the cab. I can just see that turning bad while tooling down the highway!

nickg

I ran a mechanical gauge for a long time, with a needle valve turned all the way down it only will drip fuel if the line breaks, most think they will soak the cab in diesel...not the case

disclaimer, fuel is not susposed to be plumbed into the cab,

Shovelhead

And the Cummins engines in Dodge Diesel trucks are not supposed to be 'enhanced' by changing injection parts..........

infidel

If you use a needle valve turned almost closed any leak will be nothing more than a very slow drip.
Fuel doesn't really flow though the line to the gauge, it just changes pressure.
I've had fuel into the cab of both my trucks with boost gauge type tubing for over 15 years without one leak or problem.
And that's with 12 valves that run about 35 psi pressure.
Then again if you can't fix the plumbing in your house without it leaking it's probably not a good idea to do the plumbing on your truck either.

KATOOM

I think that even though some have had great luck by doing so, its still illegal in some situations to run fuel in the cab. I wouldn't trust a fuel leak to only "drip" either. The hole in the snubber is .004 and if for some reason all broke loose, thats large enough to pass quite a bit of fuel in a short amount of time. But if there was a small weaping leak then sure, you'd think you'd catch it before anything was damaged.

Many years ago in a different vehicle, I had an aftermarket mechanical oil pressure gauge in the cab. It was plumbed with the same 1/8" plastic line as the fuel pressure gauges today. The line cracked at the back of the gauge while driving during the night. The only way I knew anything was happening was that my feet got very warm. By the time I pulled over and could tell what was happening..........you can imagine how much oil was everywhere. Caused lots of damage and ruined a good pair of shoes.

dodgeguy71

Ohhh, not good Katoom! I've been hashing it over, more so now that I'm driving and my mechanical gauges(egt,fuel pressure) don't work. Thinking I'll get a backup fuel pressure with backup transducer and electronic gauge. Then get a "T" to plumb into my lines for the Fuel Boss and call it good. Sad I've got $600 worth the gauges just to monitor this thing!

nickg

katoom

unhook the line stick it in a bucket start truck and see what happens, I bleed mine one time and it took forever to get a teaspoon of fuel out of the line, I had to go open up the needle valve to get it to move any amount of fuel,

you cant compare the 1/8 oil pressure line to the fuel line with a needle valve

still each to his own

infidel

My understanding is running fuel into the cab only applies to gasoline and is only in some states.
My feeling is it's vendors trying to make an extra buck selling isolators who pass on the rumors that they're required everywhere.
Some won't even sell you a FP gauge without an isolator.

KATOOM

Hey nickg, I'm not trying to downplay your opinion but just a friendly conversation here. My take on it is in reality the needle valve is something adjustable where as a snubber fitting is not. The snubber orifice is .004". I can blow enough air through that to feel so without dissembling my gauge setup, if I can blow air through it then I'm sure it can flow enough fuel to create a healthy little stream while under 15 psi. In saying that, there's no way for me or you to know what size the needle valve opening is in relation to the snubbers .004".....or whether or not how far you adjusted your needle valve is actually right, wrong, or otherwise. If it took you a long time just to get a TS out of your gauge line then I'd think that your setting is way too small since the gauge has to be able to read pressure fluctuations reacting as fast as you stomping on the throttle. Yes as long as there's any amount of opening then the pressure will change but its more important to know what the FP is doing now, not what it was doing. The reason for the snubber (or needle valve in your case) is to limit the "rapid" back and forth bouncing from the pulses.....not shut the flow off so much that it would take 10 seconds to respond. But really, it doesn't even matter to me since ANY amount of fuel in the cab is too much.

And just curious but why do you say that the 1/8 oil pressure gauge line doesn't compare to the 1/8 fuel pressure gauge line? Its the same exact stuff.

I may be way off base here and yes, you're right on the money by saying, its all to each is own.

nkennedy

I don't have an isolator, but my fuel pressure gauge is on the bottom of the dash. I removed the lower power plug, below the lighter, and put the gauge there. I ran 1/8 inch SS tubeing in to it. I do understand your resistance to fuel in the cab; however, I am willing to take the chance.

nickg

needle just cracked enough to make gauge read, gauge reads quickly, no delay time, volume is not important as the pressure is.

what I meant about the 1/8 line is that that oil line has no snubber/needle valve and would make a HUGE mess, as you described above compared to a 1/8 line with a restriction in it.

one day when your bored try leaving the line open with a catch can just for fun....

actually I might be able to do it easier on my 3rd gen as I have to replumb it any way, I'm set up with oil line and a needle valve, I'm off for the next 10days so I might have time to experiment