For Lift Pump Pressure . You can leave this gauge permanently in place so  you can check your pressure anytime to get on top of diagnosis of problems.

Includes a 1.5" Liquid Filled stainless case gauge and with brass internals.  Also includes a solid brass in-line fuel gauge adapter to mount on TOP of the shrader valve - after you remove the core  to mount it right on your fuel line on most 6.5's.  GM epoxies those Schrader valve in and they sometimes twist off instead of unscrewing.    We recomend you install a ball valve also  so you can block of to the gauge ore want to remove it put anything elese on like a fuel tap to draw of fuel for testing etc.  You will need at minimum a 1/8 NPT coupling if you are going to direct mount it under the hood

The 6.5 GM diesel is particularly finicky about fuel pressure and GM has actually spec'ed the lift pump which is too small in spec of 6 to 9 psi.  A 6.5 :"may"  run with low or no pressure, but you are damaging your Injection Pump if you allow it to do so.  the DS-4 Injection Pump on that motor uses "immersion lubrication" and depends on 5 PSI to force fuel oil into and through moving parts internally to keep it cool anr running properly.  Loss of supply pressure will produce a hesitation or "hiccup" or be just plain FLAT on acceleration. Also hard starting and stalling. Without supply pressure, the injection pump is forced to try to  "suck" fuel from the tank instead of being "fed" fuel by the supply pump, which puts undue stress on the injection pump by overheating and providing inadequate internal lubrication and will lead to pre-mature injection pump failures. Normal supply pump pressure according to Stanadyne is supposed to be 5psi idle thru full rpm.

NOTE: This gauge will not work in any  pillar pods unless you make a spacer to bridge the gap to 2 1/16...

1) it will not fit, it is just 1.5" in diameter and the pods take 2-1/16" gauges

2) it is technically not wise and in some places is illegal to mount a mechanical fuel filled  fuel pressure gauge inside the cab.

This gauge has 1/8" NPT male threads which come out the back of the gauge. This gauge is a top quality gauge made with a black steel case.

0-15 PSI air pressure gauge with a 1.5" dial plate.
Liquid filled for steady readout
Made with a black steel case, durable for use.
1/8" male npt threads, which measure about 3/8" outside diameter.

Material: Steel
Pressure Range: 0-15 PSI
Threads: 1/8" NPT
Dial Plate Diameter: 1.5"
Item Weight: 51g / 1.8oz
Package Size: 4.5 * 4.5 * 4.2cm/ 1.77 * 1.77 * 1.65in
Package Weight: 58g / 2.05oz

Package List:
1 * Pressure Gauge  ONLY
Electrical items are not returnable


Put any special requests in the notes section at checkout - if it cannot be done your money will be refunded immediately

See also and  for a non-mechanical version that can  be lawfully mounted in the cab


You need dual alternators to run any decent sized Hydrogen Generator system and the pump required to feed it at idle as a single alternator will not put out enough amps - even a high amp one