Adding Fuel PSI Gauges questions

CurrentSea

CurrentSea

Active member
Member
Joined
Sep 23, 2002
RO Number
10265
Messages
9,958
I bought a bunch of PSI last year and never installed. I was going to add them when I change my filters but wanted to ask some questions first. I know some of you have these installed.

1) Does this get installed before or after the first filter or does it matter?

2) When threading this on, I remember someone saying don't use teflon tape, do you use anything on threads?

3) What is the risk installing this? I know on my motors there is a warning about the high PSI for fuel lines, could this thing get blown out if pressure is too high or is that pressure more after the filters and into the motors?

Any install advice is appreciated. My plan was to install one on the dirty filter, run it, see what it reads, then change the filter, so I can get a feel for before and after readings. I usually change filters after first tank of new season.

Thanks!
 
Usually used to measure vacuum between the first filter and the tank. Installed on top of the racor in place of the T handlenot on the on engine filter. Yes your common rail engines have very high pressure after the fuel pump. teflon is never used because it can clog injectors. A little rector seal is what I always used and keep it off the first or front threads of the gauge.

Unless it has a read and hold feature it wont help much because you would have to watch the needle at speed.
 
Does not have the read and hold feature, so is it a waste to add?
I don't have racors like that.
So I was going to install sideways in one of the extra ports. Filter has 2 ports in and 2 ports out.
So I would install on 1 of the in ports?

I thought I read that the hold feature was nice but not needed since a dirty filter will show high pressure at idle as well?
 
the ones I know are used to measure supply vacuum. with racors. I am not as familiar with your system.
 
On most engines, there is no pressure before the fuel pump, only vacuum.

If these gauges only measure pressure, they will not register if installed before the fuel pump. I would not recommend installing anything on the pressure side of the pump.

If you install a vacuum gauge that does not have a hold feature, it may not tell you if you have a problem. While it may register higher at idle, you really need to track the vacuum under load. By the time you notice it at idle, a clogged filter is already affecting your engine big time under load.
 
The vacuum pressure gauges is generally installed just after the filter/separators whose condition they are intended to help indicate. Normally that is just after the primary remote filter, though an elevated reading can be caused by a restriction anywhere upstream of that gauge . It wouldn't alert to a restriction farther downstream but that happens less frequently.

Nothing wrong with installing one after the last main filter in the system , but an elevated reading would include a little longer list of suspects upstream. That would still be very helpful in providing confirmation an upstream issue must be addressed before possibly having to deal with fuel issue downstream on the engine.

Vac gauge use is fine and a very good idea on diesel engines but most vac gauges are not approved for gas I/B ot I/O use due to their glass lenses and vulnerable seals.

You are correct Teflon thread tape should best be avoided for fuel fittings.Mostly because any fittings which are disconnected may leave tape streamers to flow downstream to screens , and small passageways or injectors . Apparently the suitable pastes tend to be less problematic in that way.
Gasoila is one suitable sealant for diesel and gasoline including gasohol:

paste:http://www.gasoila.com/products/pipe-thread-sealants/gasoila-e-seal-thread-sealant.html

Permatex and others make several suitable sealants for threaded diesel fittings.

https://www.jamestowndistributors.com/userportal/document.do?docId=563
 
Its a vacuum gauge I saw on ebay.
Stainless steel with brass fittings.
No name brande
 
FWIW- At least one of the Racor vac gauges ( and probably other brands too) have a max vac re-settable needle that Capt Steve noted above, so the engine doesn't need to be running to check whether upstream flow has been restricted since last re-set.

Here's one:
http://www.parker.com/literature/Racor/Racor_Fuel_Filtration_-_Vacuum-Gauge_-_7700.pdf

It even has a "change-out line" on the inside of the lens and the bezel can rotate the line for user preference for his engine max restriction specs..
 
You must log in or register to reply here.
Back
Top