To check fuel pressure on a 12 valve

illflem · 04-03-2009, 02:15 PM

Drill and tap the top of the injection pump banjo bolt to 1/8'' pipe
thread, then install a male x female 1/8'' needle valve with 1/8'' tubing
compression fitting in it. Boost gauge or oil pressure tubing pushed
though some 1/4'' tubing to protect against cuts and kinks to the gauge.
For a 12 valve the gauge must be at least 40 psi, 60 psi is best. The gauge can say boost, air, water, fuel or nothing on it,
they will all work excellent.

Use no Teflon tape, it doesn't work with diesel.
Instead use anti-seize or Permatex #2. Remember you are
working on the clean side of the filter, keep everything spotless.
Compression fittings with a ferrule that slips over the tubing will leak
if overtightened, finger tight with one half turn of a wrench is plenty.
The ferrule should be replaced if the fitting is ever removed.

If you can tap your manifold for a pyro tapping the banjo bolt is a piece
of cake. Just drill from the inside to keep the hole straight and tap from
the outside.

You can also connect to the bleed screw on top of your fuel
filter with the appropriate adapter to tubing if you don't want to tap.
The adapter is available from TST for $25 they say it is for temporary use only Fuel Pressure Adapter .
I can see why it's not for permanent use, seems like the small bolt would break easily from engine vibration.

After the install start your
engine with the needle valve closed then open it slowly till someone in
the cab signals you that it's just reading pressure. If you tighten down
the packing nut under the valve handle the setting can't move. The valve
will control pulsation and buzzing and can also be shut down in the
unlikely event that you have a leak. Without a valve to restrict the flow
the gauge will pulsate so badly that you won't be able to read it in the
short time before it self destructs.
Cummins' pressure specs are 17-22 psi at idle, 25-35 at 2500 rpm no load,
Pressure should never drop below 25 psi under load.

Parts list; 1/8'' needle valve - $2.50 from the hardware store, plastic
oil pressure tubing kit that comes with the compression fittings - under $10
from any auto parts store. 1/4'' tubing for protective sleeve - less than $2.
Gauge is your choice and may come with tubing. The pressure gauges I
use cost around $10 from here Surplus Center
Check back if you don't see a gauge you like, their stock changes weekly.
From Grainger, needle valve Valve,Needle,1/8 In

It won't cost you much at all for a gauge that besides keeping you from walking
will eliminate unnecessary fuel filter changes, paying for itself rapidly.
I can usually go at least 30k between changes.

Needle Valve Installed On Injection Pump

__________________

__________________
Bill
'95 2500 4wd auto
'95 3500 5 speed heavy hauler
Not stock

Last edited by illflem : 04-18-2009 at 09:48 PM.

BBRam · 04-03-2009, 02:16 PM

Thank you Bill !!!!!!!!!!!!!!

__________________

03-3500, DRW, QC, 4x4, R850 BD Twins, BD IC Boots, BD Billet Flexplate, Full Billet DTT Trans, Lockup Switch, SMARTY TNT-R / TS MP-8, Wicked Diesels Eliminator Fuel System & Coolant Bypass, Floor It Stage 3 CP3 & Rail Cap, BIG Stix's by FTE, ARP Head Stud's, Springs, Fluidampr, ATS ARC-FLOW, Mag-Hytec, AFE, Boost, Drive Pressure, Pyro, Fuel Pressure, Tran's Temp, Rail Pressure Gauge, GDP Ladder Bars, GrandRock 7" Miters. (R/T .021, 60' 1.76, 1/4 ET 13.03 @ 102.05 mph)

July 2009 Cummins Forum ROTM Winner

95 1500 Sport 2wd Cummins Drag Truck under construction.

"In search of the Magic Dyno"

04-03-2009, 02:15 PM	#1 (permalink)
illflem Moderator Join Date: Nov 2005 Location: Montana Posts: 4,961 Thanks: 4 Thanked 143 Times in 131 Posts illflem's Truck Pics	To check fuel pressure on a 12 valve Drill and tap the top of the injection pump banjo bolt to 1/8'' pipe thread, then install a male x female 1/8'' needle valve with 1/8'' tubing compression fitting in it. Boost gauge or oil pressure tubing pushed though some 1/4'' tubing to protect against cuts and kinks to the gauge. For a 12 valve the gauge must be at least 40 psi, 60 psi is best. The gauge can say boost, air, water, fuel or nothing on it, they will all work excellent. Use no Teflon tape, it doesn't work with diesel. Instead use anti-seize or Permatex #2. Remember you are working on the clean side of the filter, keep everything spotless. Compression fittings with a ferrule that slips over the tubing will leak if overtightened, finger tight with one half turn of a wrench is plenty. The ferrule should be replaced if the fitting is ever removed. If you can tap your manifold for a pyro tapping the banjo bolt is a piece of cake. Just drill from the inside to keep the hole straight and tap from the outside. You can also connect to the bleed screw on top of your fuel filter with the appropriate adapter to tubing if you don't want to tap. The adapter is available from TST for $25 they say it is for temporary use only Fuel Pressure Adapter . I can see why it's not for permanent use, seems like the small bolt would break easily from engine vibration. After the install start your engine with the needle valve closed then open it slowly till someone in the cab signals you that it's just reading pressure. If you tighten down the packing nut under the valve handle the setting can't move. The valve will control pulsation and buzzing and can also be shut down in the unlikely event that you have a leak. Without a valve to restrict the flow the gauge will pulsate so badly that you won't be able to read it in the short time before it self destructs. Cummins' pressure specs are 17-22 psi at idle, 25-35 at 2500 rpm no load, Pressure should never drop below 25 psi under load. Parts list; 1/8'' needle valve - $2.50 from the hardware store, plastic oil pressure tubing kit that comes with the compression fittings - under $10 from any auto parts store. 1/4'' tubing for protective sleeve - less than $2. Gauge is your choice and may come with tubing. The pressure gauges I use cost around $10 from here Surplus Center Check back if you don't see a gauge you like, their stock changes weekly. From Grainger, needle valve Valve,Needle,1/8 In It won't cost you much at all for a gauge that besides keeping you from walking will eliminate unnecessary fuel filter changes, paying for itself rapidly. I can usually go at least 30k between changes. Needle Valve Installed On Injection Pump __________________ __________________ Bill '95 2500 4wd auto '95 3500 5 speed heavy hauler Not stock Last edited by illflem : 04-18-2009 at 09:48 PM.

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04-03-2009, 02:16 PM	#2 (permalink)
BBRam Super Administrator Join Date: Jan 2006 Location: Chelsea MI Posts: 23,419 Thanks: 173 Thanked 248 Times in 162 Posts BBRam's Truck Pics	Thank you Bill !!!!!!!!!!!!!! __________________ 03-3500, DRW, QC, 4x4, R850 BD Twins, BD IC Boots, BD Billet Flexplate, Full Billet DTT Trans, Lockup Switch, SMARTY TNT-R / TS MP-8, Wicked Diesels Eliminator Fuel System & Coolant Bypass, Floor It Stage 3 CP3 & Rail Cap, BIG Stix's by FTE, ARP Head Stud's, Springs, Fluidampr, ATS ARC-FLOW, Mag-Hytec, AFE, Boost, Drive Pressure, Pyro, Fuel Pressure, Tran's Temp, Rail Pressure Gauge, GDP Ladder Bars, GrandRock 7" Miters. (R/T .021, 60' 1.76, 1/4 ET 13.03 @ 102.05 mph) July 2009 Cummins Forum ROTM Winner 95 1500 Sport 2wd Cummins Drag Truck under construction. "In search of the Magic Dyno"