got a 0-30psi. Isspro FP gauge bought for the 01' & it doesn't come with an isolator, I've read that you really need one, & also heard that it doesn't matter???? so what should I do??? & if I need an isolator where's the best place to get one & about how much should I expect to pay for one??? thanks alot, Dusty

 

Use an isolator only if your goal is to have a gauge that reads wrong and isn't reliable.

 

10-4 thanks, what about a needle valve?? think I've read somthing about some guys using a needle valve?? I've never ran a FP gauge before, just the FP on the Juice I had on my other 01' & it was simple enough!!!LOL thanks alot, Dusty

 

I have to disagree with ya here Bill. I don't think either is a bad way to go as long as it's done right.

The DiPricol with isolator I have on my truck has been very accurate. I've checked it against a gauge without an isolator a half dozen times in the past two years and it has always been within 1lb.

It's all a matter of personal preference. Do you want fuel in your cab or not? I didn't so I chose an isolator and haven't had any issues. I probably wouldn't have any issues if I didn't have the isolator either.

 

smokin, most likely the reason your gauge with isolator is working so well is because the diaphragm in the isolator ruptured in the first 1000 miles or less and diesel is in your cab without your knowledge. I've checked quite a few isolators of different brands on different trucks, every single one of them had ruptured isolators. My only conclusion is isolators don't work on diesel engines, the isolator turns into an expensive coupling.

 

I use a needle valve with no isolator.I never had a problem.Your pressures are not going to be that high.(We are not talking high pressure Hydraulics) I never had a fuel leak.If I did ,I would just shut it off at the valve. What ever you do put a valve in.

 

thanks john, that's kinda what I was thinking, I'll let ya'll know how it goes when it gets here, thanks again, Dusty

 

Bill, I've removed my gauge to reposition it a couple times to accommodate other gadgets and each time it dumped antifreeze out, never fuel. I actually disassemble it at the firewall and refill it with antifreeze. Maybe I got lucky.

I do remember questioning Mark Chapple about the isolator when I bought it a few years back. He assured me that it would not fail because it was specifically for use with diesel fuel. Is it possible that many of the isolators that are issued with a fuel pressure gauge are just a generic variety that were not intended to be used with diesel?

 

Dont do it Dusty

the above statement is correct.... I had one, ditched it, problems solved... Just run the fuel straight into it.. Ull be glad u did, dont worry about leakage, just use a good permatex or gasket maker...

as stated do the needle valve instead...

Rick

 

that's the plan Rick!! thanks for the input though, I'll just do the needle valve & leave it at that!! Dusty

 

i have an isolator on mine. I know the diaphram is good because i have a clear nylon tube running from it to the gauge.

anyone running a isolator know how to get the nylon tube full of antifreeze? i used a needle to fill it when i installed it, but couldnt get it completly full. i have probably ten or so inches of air.

 

That doesn't mean anything, most of the broken ones I've found still had antifreeze in the gauge side of the isolator. Only way to know for sure if the diaphragm is cracked is to loosen the gauge side line at the isolator with the engine running. If fuel comes out the isolator is shot.

 

Have done this check a couple of different times and no fuel coming out yet. Course it's only been on there a little over a year. I'm wanting to go to an electric FP gauge but I want either the lunar or NV autometer and havent found one except 0to100 psi, wouldnt that be a useless parameter? Since at idle I'm only at 25 psi WOT around 12psi

 

When I was fighting with my isolator (before I threw it out) I thought my problems were due to air in the antifreeze line so I removed the line from the fuel guage and put it in a bottle of 50/50 mix antifreeze and water, blew all the old antifreeze mix out of the line and sucked the other end of the hose until I had a mouthful of antifreeze using my finger on one end of the hose I reattached the other end to the isolator. Oh yah, I had completely filled the isolator with a syringe before this. Once I had the isolator installed again I was only missing a few drops of antifreeze in the end of the line, again with the syringe filled it full. Still had problems with the readings so I pitched it.

Good luck.