Major problem I had today, if anyone can help. I installed a mechanical psi gauge
and used a PDR diesel performance type isolator http://www.piersdiesel.com/techisolator.htm with a 3/8” rubber line running from a needle valve at the VP44 inlet area to the base of the isolator and a very small nylon type line through the firewall over the steering column and down to the gauge just over the trans hump at the floor. I followed the isolator charging instructions that said nothing about putting fluid in the line to the gauge, just in the top of the isolator. Well I fired the truck and bleed the isolator on the fuel side adjusted the needle valve, but never got over 8psi. When I turn the key and the pump cycles (hums) the psi hits 10, then drops to 8 or just a bit over when the truck starts. If I stomp on it WOT, it stays at 8 and doesn’t move, the gauge only moves when I shut the truck down.

I know most of you advised that I not run the isolator, but my young kids ride with me and its better to be safe. But I need some help. I ran out of day light so I was thinking I’d open the top of the isolator tomorrow and put in more glycol. Other than that I don’t know unless I put some down the line to the gauge. It acts like the line has air and isn’t getting the psi it should have with the big line of 13 plus. I do have another newer Carter (the one without the wire leads) and I can try that one once I fix the frame mounting bracket.

Thanks for any input. I know I can swap the rubber/nylon line for a diesel line to the gauge, but I paid quite a bit for this thing and it should work.

Thanks for the help.

 

I filled my line up antifreeze even though i didnt have to per the instructions. Figured it couldnt hurt. When I redid the fuel system I got rid of the needle vavle and noticed my FP quit reading. The nylon seal got smashed and actually blocked the fuel. It started before I took the schrader valve out as well.

 

I just got done installing an Issopro fp guage in my truck and I installed the isolater. According to the instructions you are supposed to fill it within 2 threads from the top with anti-freeze. I did that and my guage works perfect.

 

not to hijack the thread or anything but why is it that people say not to have diesel fuel in the cab...."better safe............" I've heard that a few times, whats the reasoning there?

Diesel fuel is not gasoline, its not exactly dangerous like gasoline? Just curious.

 

I don't know I was told by a big rig driver that it will not burn like gas and that there are cleaners to get it out of the floorboard and such. I'll try to fill the line did the fill to two threads like hdgauge said and tapped the glass and it was reading about 10psi. I'll pull the line from the gauge and fill from the top down install the line and max out the isolator, if it's the same I'll bypass and run the diesel. I've spent two days messing with this and the LP's.

Thanks for all the info.

ed

 

Granted I've only removed isolators from about ten rigs but every single one of them had ruptured the inner diaphragm and fuel was going all the way to the gauge without the owner's knowledge. I highly doubt any isolators make it even 1000 miles.

I wonder if people who worry about fuel in the cab also worry about their house plumbing being in the walls. Never know, your plumbing might be leaking in the wall and you wouldn't know until it's too late.

In both cases just a few common sense plumbing practices and you won't have any leaks. Main problems people get into is overtightening and using teflon tape.