Fuel pressure gauge, with or without isolator?

[JGoss]

I'm getting a Isspro fuel pressure gauge and questioning the need of an isolator. What are your comments on them? It's about $110 dollars for the isolator and S. S hose, so is it worth it?? Thanks

 

[Blu-meanie]

I put one on mine, but I've run lots of oil pressure gauges on many vehicles without a problem.

If it was gas, yes, definitelly. Diesel, will just stink up the cab if it leaked. A copper tube would be a better choice for a direct hook-up.

 

[SMcGrady]

I'm getting a Isspro fuel pressure gauge and questioning the need of an isolator. What are your comments on them? It's about $110 dollars for the isolator and S. S hose, so is it worth it?? Thanks

I got the isolator and fuel line (not S. S. ) from Genos. Easy to set up and it works very well... Glad that I won't have to worry about diesel spurting in the cab if the connection ever comes adrift...

Scott-

 

[ENafziger]

I put one on mine. Fuel additives destroyed it in short order. Took it out, and things work great.

--Eric

 

[Pliska]

I put one on mine. Fuel additives destroyed it in short order. Took it out, and things work great.



--Eric

Are you saying the isolator failed due to fuel additives? Was it an ISSPRO isolator? If so, did you send it back?



Thanks,

Michael Pliska

 

[hsmith]

I put two without the isolator on my '96. Both leaked at the bezel in short time. Had the snubber really choked down too.

 

[SMcGrady]

I put one on mine. Fuel additives destroyed it in short order. Took it out, and things work great.



--Eric

I'm curious about this too... What brand of isolator and what fuel additives??



Just talked to Geno's about the isolator that they sold me. The guy I spoke with said he saw your post too, and he was curious to see what Pliska says... (Me too!)



He also told me that diesel fuel will ruin your gauge if you don't use an isolator, and if you choose not to use one, it will void the warranty for ISSPRO gauges (and at least one other MFG that I believe he mentioned).



Finally, he said that he had never seen one of these isolators fail (due to fuel additives).



I would really like to hear from anyone else that has had a failure of their isolator (for any reason)...



Thanks,

Scott-

 

[hsmith]

So does the isolator keep all fuel from the gauge? If so, I will install mine and see what happens.

 

[ENafziger]

Are you saying the isolator failed due to fuel additives? Was it an ISSPRO isolator? If so, did you send it back?

Maybe I should've clarified. I was speaking of isolators in general, and not necessarily ISSPRO.

I ordered a bunch of DiPricol Optix series gauges from Diesel Manor, and also purchased the fuel isolator as recommended. I'm not sure what brand it was... it was recommended as a safety feature, so I bought it.

It wasn't long after I installed it that my fuel pressure gauge became somewhat erratic, and then showed "0" pressure. I assumed it was the Walbro lift pump gone bad, and so I ordered a new one.

Meanwhile, I hooked up a manual pressure gauge under the hood, before the isolator, and pressure indicated the normal 18 psi. Thus, I determined the problem was not with the lift pump, but was with the gauge. I left things like this for almost a year. One day, I decided to bypass the isolator just to see what would happen. The DiPricol fuel gauge immediately started working, and has been fine for the last 4 months. I am not using an isolator or a snubber, and I get no needle fluttering on the gauge.

The isolator originally failed soon after the introduction of the new '07 ULSD fuel, and I thought that was the cause. However, several other people who also are using an isolator from DieselManor have not had problems, even with the new fuel. Thus, the only thing I could come up with, is the additives I was using at the time contributed to the failure.

Up to the point of failure, I religiously used a mixture of Power Service and Marvel Mystery Oil as fuel additives. However, after reading the report that came out on lubricity of different additives, I immediately ceased using both of these products. FWIW, I now use Schaeffer's diesel treat, and also try to run around 5 - 10% bio.

--Eric

 

[SMcGrady]

So does the isolator keep all fuel from the gauge? If so, I will install mine and see what happens.

Yes it does. . The way I understand it, the isolator has a flexible diaphram in it that seperates the fuel (supply) side from the antifreeze (gauge) side.



I don't need/use a snubber with this set-up and it works very well.



Scott-

 

[hsmith]

So my guess would be now that my gauge was leakin diesel, with the isolator it would probably leak antifreeze? May have to replace the gauge again, getting a little irritated having to pull the a-pillar again.

 

[SMcGrady]

So my guess would be now that my gauge was leakin diesel, with the isolator it would probably leak antifreeze? May have to replace the gauge again, getting a little irritated having to pull the a-pillar again.

If I remember correctly, I believe that the guy at Geno's told me that not using an isolator will cause to the gauge to fail and leak, sooner or later... and it won't be covered by the warranty...

If that is true, your gauge could be ruined and would probably continue to leak even if you put in an isolator... kind of like closing the barn door after the horse has gotten out... Hope you get it sorted out.

Scott-

 

[hsmith]

Kinda what I am thinking. I used someone else's info on not using the isolator. Not trying to raise a warranty issue here, but would like to have a dependable unit. Have read where some leak antifreeze from the isolator too.

Oh well, will be a couple of weeks before I can get behind the wheel or even open the hood, so will do something later. Think a chat with a Isspro rep may be in order.

 

[Pliska]

ENafziger,

did your isolator actually leak (visible fuild coming out of it), or did the gauge just quit working? I wonder if the antifreeze leaked out through a fitting?



hsmith,

Were these ISSPRO gauges which started leaking? Did you return them? I am interested, as I had not heard of this failure more. Bourdon tubes are typically pretty durable, as long as they do not get significant overpressure. The gearing mechanisms will wear out, though, if you don't use a snubber to eliminate the pulsations from a mechanical lift pump.



Regards,

Michael Pliska

 

[WStephens]

I use an isolater for my fuel gauge and last summer on my way back from Wyoming it was showing low pressure. I though my filters needed to by changed but found that the antifreeze has gone. I refilled the isolator and it has been working ever since but the pressure is a little lower than it was when it was first installed. So now as part of my maintenance I will check the fluid in the isolator and make sure that the diesel side has all the air bleed off.

 

[SMcGrady]

I use an isolater for my fuel gauge and last summer on my way back from Wyoming it was showing low pressure. I though my filters needed to by changed but found that the antifreeze has gone. I refilled the isolator and it has been working ever since but the pressure is a little lower than it was when it was first installed. So now as part of my maintenance I will check the fluid in the isolator and make sure that the diesel side has all the air bleed off.

The antifreeze should not just disappear. What brand of gauges do you have? I understand that some brands have better connection fittings than others... Any idea where the leak occured? Gauge side or at the isolator? If your antifreeze is disappearing, you have a leak at one place or another or your gauge itself is leaking... Double check all the connections and try to determine if/where any further leaks are originating...

Scott-

 

[RDyson]

I have Isspro gauges that I also bought from Diesel Manor. They have been in the truck for 4 years with no problems. I have the isolator on my fuel pressure gauge and would not run one without it. I wouldn't want a fuel leak in the cab.



I have ran Powerservice and 2 stroke for additives--no problems here.



Randy

 

[hsmith]

Yes Michael, both were Isspro. First was the 30# from Geno's. Started leaking at the bezel within 500 miles. So I said I should have not used the 30# on a 12 valve, and ordered the 60# from Diesel Manor. Same story. I did not use the isolator, but did have the snubber really choked down. Also, have not raised any warranty issues with either, since I figured it was my fault for not using the isolator.

Thanks for the input.

 

[hsmith]

Just went to DM site and it said the isolator was to be used only if installing the gauge inside the cab. Tells me it is only for safety and not performance or durability of the gauge.

Oh well, as soon as I am able function again, I will do some more checking.

 

[ENafziger]

ENafziger,
did your isolator actually leak (visible fuild coming out of it), or did the gauge just quit working? I wonder if the antifreeze leaked out through a fitting?

I didn't notice any visible leaking of the isolator. The gauge simply quit working. When I bypassed the isolator (just connected the lines coming into and out of the isolator) the gauge worked perfectly.

If there was a leak that allowed the antifreeze to escape, I'm sure I would be noticing leaking diesel fuel, as the same lines and connections are still in place.

If I recall correctly, the installation instructions said that antifreeze wasn't even necessary on the downstream side of the isolator if the run to the gauge was 6' or less.

I've not spent much more time looking into the isolator, as my gauge is working fine without it, and there are alot of other things on my to do list. Maybe one day I'll pull it apart and inspect...

--Eric