cummmins 5.9 fuel pressure gauge

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billy

Motor mouth ratchet jaw!
Joined
Nov 15, 2009
Messages
3,935
Location
helifino USA
ok fellas
i tried asking this on 2 different cummins forums
and either there is zero traffic on those sites
the question is so elementary they dont bother answering
or they hate newbies;)
i have a 2001 ram 5.9 HO cummins
with FASS DRP 02 block mounted lift pump
no other mods
i have a 0-30 PSI liquid filled mechanical fuel pressure gauge, a threaded banjo bolt and 25 feet of 1/8 OD nylon tubing rated for 250 PSI max
i dont want to use an electrical sender
just simply run the gauge into the cab
should i replace the banjo bolt on the bottom of the fuel filter canister and run it like that or?

normally i prefer copper line but with the vibrations this engine produces i dont think it would last long.
before anybody warns me about fuel in the cab
i would like to point out that for generations airplanes and semi trucks as well as all sorts of heavy equipment have been doing it all along:D
as always
i thank you
my mother thanks you
my father thanks you
etc.......[cl
 
It sounds like a good idea. I would think that there is a port for testing the pressure between the primary and injector pump that you plumb into but don't know this for sure. try googling primary or lift pump pressure test port location and see what comes up. good luck
 
It sounds like a good idea. I would think that there is a port for testing the pressure between the primary and injector pump that you plumb into but don't know this for sure. try googling primary or lift pump pressure test port location and see what comes up. good luck

there is a schrader valve for testing
but i want to leave that free for gauge verifying
 
Diesel would not be as bad in the cab as gas, but it would stink and be greasy. They make an isolator for fuel pressure gauges, it contains a fluid that won't burn or stink up your cabin. It goes inline, outside of the firewall to the gauge. I'm not sure where to get it, Jegs or Summit maybe. It would be as safe as mounting it on the cowl using the isolator.
 
my past builds /projects all had mechanical gauges and never a leak
i realize there is a first time for everything but i dont see a need for an isolator
 
i figured it out
tapped snubber bolt goes on the input of the vp44 with a needle valve (in case of leaks) then run the air brake tubing to gauge
 
i removed the banjo bolt from the botom of the fuel filter housing and replaced it with a tapped one from TORK TEK
12mm banjo bolt pressure gauge snubber #BBS010
then ran my tubing straight through the firewall to the gauge
i ran it through an existing grommet
and since i have to pull the dash soon to replace the heater core
i put a hunk of velcro tape to the bottom of the gauge and stuck it to the dash rug.[cl
 
Last edited:
If I remember correctly' if your installing on the vp44, the snubber valve is also to help minimize pressure surges (hundreds per minute) the vp44 creates. I know on electrical senders, that pulsation would kill them. Went through 2 or 3 on my 98.5 before I traded it in.
I'm a 3rd gen guy now and use a banjo bolt on top of the fuel filter canister. Until I got the airdog. Need to install on the airdog someday.

Just out of curiosity. What pressures are you seeing with the fass?
 
If I remember correctly' if your installing on the vp44, the snubber valve is also to help minimize pressure surges (hundreds per minute) the vp44 creates. I know on electrical senders, that pulsation would kill them. Went through 2 or 3 on my 98.5 before I traded it in.
I'm a 3rd gen guy now and use a banjo bolt on top of the fuel filter canister. Until I got the airdog. Need to install on the airdog someday.

Just out of curiosity. What pressures are you seeing with the fass?

16psi at idle
never below 11 at WOT under load
 
Billy this is a bit lengthy but, worth the read.
This came from the Diesel Bombers website by the way.
http://www.dieselbombers.com/diesel...et/72316-01-cummins-fuel-pressure-issues.html

BOSCH VP44 INJECTION PUMP AND LIFT PUMP FAILURES EXPLAINED

"The best way to start this explanation is to quote an e-mail that was found on the Cummins website. “The Bosch VP44 has not been as reliable as we had hoped”. Depending on who you talk to and who you think is being honest, you will most likely get only some of the information you need. I will endeavor here fill in the gaps and get you up to date and informed; the reason I can tell you more is because Bosch had not, until 2004, allowed any franchised dealer to do anything except to send defective pumps back to the remanufacturing facility. Long before that Blue Chip had dismantled many pumps to figure them out and diagnose what failed and what caused the failure. We do not pretend to be any where near as smart as Bosch, but since there was no experience or information or truth out there, we felt we had to get the best information we could any way possible. Probably the most informative source were the applications for the patents applicable to the VP44. It was this dismantling and learning process that allowed us to get a patent and a performance product to market first.

The most common MECHANICAL failure with the VP44 pump is the cause of the code 216. This is when weak lift pumps with low fuel pressure over a perioid of time rupture the diaphragm in the front of the injection pump and the timing piston then vibrates and wears the housing of the pump until fuel bypasses the piston and full advance can no longer be attained. When full advance can't be attained for more than 5 seconds the code 216 is set. This means your pump has lost a lot of its power and fuel mileage and needs to be replaced and upgraded.

The next most common MECHANICAL failure is that the rotor seizes in the distributor section of the pump. I should note here that all previous rotary style pumps have had this problem too, to varying degrees. The most common cause and most accepted reason for this failure on rotary pumps is lack of lubrication due to running out of fuel or the possible lower lubricity of the newer low sulphur fuels.

In the case of the VP44 it is more common for the rotor to seize in the distributor because the pressures are MUCH higher and therefore mechanical tolerances have to be much smaller. Add the fact that the rotor was not "deburred" enough or correctly during manufacture, and these failures can be easily explained. Under the higher working pressure in the VP44, the edge of the slot in the rotor deflects and interferes with the distributor. Sooner or later the result is a galling of the two parts and then binding and then seizure. The seizure causes the "Drive Plate" to break and the truck stops running, never to start again until the VP44 is replaced. There is less than a half a thousanth of an inch clearance between the two parts, so it doesn't take much to make the rotor interfere with the rotor. Pumps made recently (since about 2000) are experiencing fewer of these kinds of failures, it seems to me.

The other reason injection pumps fail is ELECTRCAL issues and failures. These are the problems that cause 99% of the drivability problems. The computer on the top of the VP44 is susceptible to heat and many many heat cycles. The components on the circuit board develop bad connections due to crystallized solder over time and the result is intermittent hard start, white smoke and drivability issues such as the common " Dead Pedal". Rarely can these issues be verified or diagnosed by codes set in the ECM.

A lot of people have heard about bad lift pumps and think they are the cause of VP44 drivability issues and therefore electrical failures; NOT SO! Starting with the early 98’s, not only were they weak pressure wise, but also had exposed terminals on the bottom that corrode off in salt environments. The way to tell if you have a corrosion sensitive pump is to see if the electrical connection is a plug on a 6-inch pigtail coming from the bottom of the pump. If the plug is on the top cover of the pump you’re all set, for that problem anyway!

If the lift pump is not delivering fuel pressure the truck stays running because there is a gear pump in the front of the injection pump, which keeps the fuel flowing, albeit at a much lower pressure than desired, and hopefully maintains lubrication to the rotor. As long as there is return fuel flow from the injection pump there is lubrication to the rotor, so low fuel pressure and certainly less return fuel makes it much easier to starve the rotor for lubrication. The only accurate way to test a lift pump is to monitor pressure UNDER LOAD and if it is above 5 PSI, no performance is lost and the pump is OK. If pressure is less than this, a modest reduction in horsepower results. The usual scenerio is a customer puts a performance box on his truck and the lift pump can't produce enough fuel to make more horsepower, and the performance product gets the blame.This sympton is most always a "Buck" as opposed to a "Surge" under load.

Often people have mistakenly said that increased pressure from add-on performance devices causes the injection pump failures. This statement only indicates their lack of knowledge, because, unlike most pumps, the VP44 pump does not create more fuel delivery by increasing lift pump pressure. The VP44 creates more fuel delivery by holding the fuel bypass solenoid closed longer. Fuel delivery pressure is controlled by the “pop off pressure “ of the injector.

The reason any aftermarket device that hooks up to the solenoid wire is blamed for the failure is that the failure 99 times out of 100 (honest numbers here) the pump fails within 20 minutes of installing and running with power enhancement. The reason this happens is because the fuel solenoid is held closed longer, therefore using more length of the slot in the rotor. The slot in the rotor overlaps a hole in the distributor to allow for different timing and amounts of fuel to be delivered to the injector and when the solenoid holds the bypass solenoid closed longer, then the high “pop off” pressure is still there when the middle of the slot overlaps the hole. The middle of the slot is the weakest area and therefore deflects, interferes with the distributor and seizes. Pump failure with fuel enhancement devices is not CAUSED by the enhancement device, but PRECIPITATED by the device. WE think this is a “glass half full” scenario rather than a “glass half empty” one, because the potential, eventual failure can be determined within controllable parameters, namely on the test run at higher power, close to home or the local dealer. The other side of the coin is, honestly, if your truck is still running 20 minutes after the installation AND BEAT RUN, you have a 90% chance your pump will not fail for a mechanical reason and therefore last until electrical issues start to show.

Lastly the installation of bigger injectors; do they alleviate the high pressure or raise the pop off pressure and therefore cause many failures of the VP44? Absolutely NOT. They are a bigger hole so fuel volume is increased at the same pressure. Remember fuel pressure is controlled by “Pop off” pressure more than the size of the hole! Aftermarket injectors that DO raise the pop off pressure do not appear to cause any problems. Bigger injectors do get more fuel into the combustion chamber sooner, therefore giving the engine better throttle response.Bigger injectors are worth it but not for the reason of saving the pump."

"Thanks for reading, Chip Fisher, owner of Blue Chip Diesel Performance"
 
Part 2

"HOW YOU CAN DIAGNOSE A LIFT PUMP

If your truck "Bucks" under hard load or towing this is an indication the engine is probably starving for fuel, due to low lift pump pressure. To test fuel pressure, install a fuel pressure gauge with a long hose on it after the fuel filter and before the injection pump. The long hose allows you to drive the truck and watch the gauge at the same time! Or..........if this is inconvenient for you come by, you can install our “Low Fuel Pressure Warning Kit” and it will diagnose low fuel pressure too.
To diagnose lift pump performance click the ignition key to the start function quickly, so the engine doesn't start, and let go, leaving the key in the run position; the lift pump should run 25 seconds. If you don't hear the lift pump, check fuse number 9 in the fusebox on the left side of the dash, and if that is good, test for 12 volts going into the lift pump and if it doesn't run with 12 volts going into it, replace it. If you do hear it run and it doesn't make at least 5 PSI replace the fuel filter. If, after changing the filter, it DOES make at least 5 PSI go DRIVE the truck UNDER LOAD. If it doesn't make at least 5 PSI UNDER LOAD after changing the filter, or if you have to pressurize the fuel tank to bleed the system to get the truck to run, then change the lift pump.
Please realize that revving it up proves NOTHING. If DRIVING UNDER LOAD the pressure drops below 5 PSI, replace the fuel filter (if you haven't already done so) and if that doesn't fix it, I am 99% sure you need a new lift pump.
Another possible cause of low pressure is rusty fuel lines, sucking air. The way to test for air in the line is to replace a section of the fuel supply line with a clear polyethylene hose, between the lift pump and the injection pump, and run the engine to see if there are any bubbles, indicating air as the culprit.
We proved on a dynomometer in 1998 that if you have 5 PSI, under load, you can make all the power available from a VP44, and 5 psi will provide plenty of return fuel for pump lubrication. We do not recommend running more than 12-15 PSI as that does NOT help the fuel system in any way. In fact higher pressures could diminish fuel delivery to the rotor and make the truck run worse at high RPM and possibly overheat and damage the fuel bypass solenoid.
This diagnosis is only for the lift pump, but is necessary for the successful diagnosis of possible injection pump issues. If you don’t have enough lift pump pressure it will ONLY cause low power or bucking under load. All other driveability issues are caused by the computer on the top of the injection pump, or by fuel contamination and stuck internal parts in the injection pump.
Replacement lift pumps that make more than 15 psi are in my mind overkill and not necessary. The FASS system is a dependable alternative and very popular, but not necessary. The "In Tank" unit sold exclusively by Dodge does NOT work as well as the old style on the side of the engine! Cummins still sells the exact replacement that mounts on the side of the engine and that is what we sell."
"Thanks for reading, Chip Fisher, owner of Blue Chip Diesel"
 
old iron
thanks buddy
i read conflicting stuff online till i got dizzy
one thing that most people agree on is that the stock lift pump WILL fail
and take the vp-44 with it.
thats the only reason i replaced it when i first got the truck.
and as far as the gauge goes
it gives me peace of mind and lets me know when to replace the fuel filters
 
You're welcome
It pays to know when our filters are starting to not allow fuel through.
The fuel we get now is so dirty that the ole mileage rule of thumb, as to when it needs changed, is out the window.
 
You're welcome
It pays to know when our filters are starting to not allow fuel through.
The fuel we get now is so dirty that the ole mileage rule of thumb, as to when it needs changed, is out the window.

i go to the main fuel station in my town that all the truckers use.
 
Having worked as a service manager at a diesel pump shop for 15 years. I saw a lot of VP 44 pump failures. The supply pump failure is the biggest cause of the VP 44 failure. Why does the supply pump fail? It is mounted in the wrong place! In my near 50 years of hot rodding, it has always been said to mount the electric supply pump as close to and below the fuel level. So the pump goes in the rear on the frame below the tank. Where did Cummins put it? Right on the side of the block, as far from the tank and fuel as they could get it. Oh and all the heat, electrical things don't like heat. We started making a simple relocation mount and moved the supply pump back next to the tank where any hot rodder would have put it. This seemed to take care of the supply pump failure and the the VP44 pump failure.

Looking for more power? Cummins made that same engine in 275HP and the only difference was the injectors. Then a bigger air filter.
 
if this FASS DRP02 ever dies (still 3 years on warranty)
i will mount the replacement on the frame.
i dont like working on this truck
i just want it to haul stuff which is what it was invented for.
i will leave the cummins hotrodding to the guys that just love to trash clutches
grenade trannys
etc.
 
since i hate wasting money because i am so poor.
instead of blowing $250 on a gauge kit
$25 jegs gauge
$8 for 25 feet of air brake line
$ 10 threaded banjo bolt snubber
then i put a hunk of velcro tape on the bottom of the gauge housing.
and stuck it to the dash rug

 

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