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the filter pictured is the last of the filters before the v44. The pressure shown is way to low for good service. I use a combination remote electronic pressure gauge to monitor the fuel pressure. About ten years ago we had issue that required the replacement of the lift pump, v44 and filters. I also had a vacuum on the fuel tank that led me to find the fuel cap was not venting and the overturn valve on the top of the tank was stuck shut causing the pump to work overtime. After the above replacement, I had to run home with a rag in the filler neck.
More recently, After I had installed the glowshift gauge, I saw a low pressure reading. I checked it with a manual gauge like your and found about three pounds. Below the minimum 5 pounds according to cummins. I replace my lift pump with a factory OEM pump and I got my 17 pounds static and 11-12 pounds at highway speeds. the factory pump is considerably less expensive than the after market variety and works just fine.
I also added a ball valve and hose after the final filter to help bleed the filter and also supply filtered fuel to fill the new filter at replacement time.
click on my blog below to see the setup.
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La Dagobago
99 36 FL Winne Chieftain 5.9 ISB Turbo Cummins DP, 24' box with HD Sporty Hobby of 1970's Suzuki dirt bike restoration. Visit my blog.
the filter pictured is the last of the filters before the v44. The pressure shown is way to low for good service. I use a combination remote electronic pressure gauge to monitor the fuel pressure. About ten years ago we had issue that required the replacement of the lift pump, v44 and filters. I also had a vacuum on the fuel tank that led me to find the fuel cap was not venting and the overturn valve on the top of the tank was stuck shut causing the pump to work overtime. After the above replacement, I had to run home with a rag in the filler neck.
More recently, After I had installed the glowshift gauge, I saw a low pressure reading. I checked it with a manual gauge like your and found about three pounds. Below the minimum 5 pounds according to cummins. I replace my lift pump with a factory OEM pump and I got my 17 pounds static and 11-12 pounds at highway speeds. the factory pump is considerably less expensive than the after market variety and works just fine.
I also added a ball valve and hose after the final filter to help bleed the filter and also supply filtered fuel to fill the new filter at replacement time.
click on my blog below to see the setup.
Thanks for the input.
I have a stock pump on order to see if it will make a difference. I'm pretty sure the LP is bad and an $80 risk is a no brainer. If it works then I'll factor in a better quality unit in the off season and put the factory unit on the shelf as a spare.
I only have one short trip for the rest of the season and don't want to dump the $$ on a high powered replacement pump/system.
I'd rather save for the complete kit (either FASS or AirDog) and run it to the rear of the coach. I think I have room near the rear propane fill port for the module, filters, and space to easily change the filters.
My stock lift pump puts out 11 lbs pressure.....Carter brand......when I had to replace the VP 44, went with one from Blue Chip Diesel....not to bad of a job changing one, if you have the gear puller....I went with one of their better pumps, and what a difference.....got 200,000 out of factory pump....
Sounds like your crankshaft position sensor is failing. I had the same symptoms as what you are describing. It took Cummins in Los Angles 3 days to diagnose. They said fuel pump failed. Then They said it was ecm had failed. That took 2 full days and still not running properly. So they put an experienced mechanic on it. 15 min found the problem. Crankshaft position sensor failing. They put motor home on the dyno . Runs great now. Crankshaft position sensor never gave a failure code. It came down to a mechanic with old fashion mechanical experience.
Good luck
I've had 2 fail, and they throw a code.....also had a boost/map sensor fail that one minute was good and the next not.....first crank sensor was a Napa replacement for the original, now has one from Auto Zone with a lifetime replacement thing....it or mine? lol.......crank sensor on mine is behind starter, and takes a 10mm wrench to pull starter and sensor retaining bolt....
I also had low fuel lift pump pressures. Cummins installed 3 new lift pumps and said that all 3 failed. Which is impossible. That’s when they said the ecm has failed. Installed new ECM one same problem. Then an older more experienced mechanic new what was wrong. Computer did not know where the crankshaft was so it would not supply full fuel. Engine was in limp mode. No fault codes for crankshaft position sensor.
I have a stock pump on order to see if it will make a difference. I'm pretty sure the LP is bad and an $80 risk is a no brainer. If it works then I'll factor in a better quality unit in the off season and put the factory unit on the shelf as a spare.
I only have one short trip for the rest of the season and don't want to dump the $$ on a high powered replacement pump/system.
I'd rather save for the complete kit (either FASS or AirDog) and run it to the rear of the coach. I think I have room near the rear propane fill port for the module, filters, and space to easily change the filters.
Be sure to get the compression washers too. The old ones should not be used over. Also, after installing the new replacement pump you may find that you are satisfied with the operation. I do not feel that the expense of the upgraded pump is worth the money. Pushing 11 pounds of fuel to the V44 is sufficient for max operation unless you have a pressure change of more than 5psi at WOT COULD ALSO indicate restrictions in fuel lines or filter too.
Correction to my previous post ::: Minimum pressure out of the final filter should not be below 8 psi for the V44.
__________________
La Dagobago
99 36 FL Winne Chieftain 5.9 ISB Turbo Cummins DP, 24' box with HD Sporty Hobby of 1970's Suzuki dirt bike restoration. Visit my blog.
First video is bumping the starter. Second is it running.
Fuel pressure is tapped from water sensor in the fuel filter housing.
Good thing is that it is greater that 0. I don't really trust the accuracy on my HF sensor since it is at the very bottom of the scale.
I find it odd that the pressure goes to 0 in the second clip with the engine running.
I cant drive test it at the moment due to the exhaust downpipe being disconnected from the muffler. I have to get a marmon joint remade so it will stay in the vband on the other side of the pacbrake.
Banjo pick-off port is on order and I'll tap off of the upper port of the filter housing to get "after filter" reading just prior to the VP.
The scale of the gauge should be 30 but still the pressure appears very low.
__________________
La Dagobago
99 36 FL Winne Chieftain 5.9 ISB Turbo Cummins DP, 24' box with HD Sporty Hobby of 1970's Suzuki dirt bike restoration. Visit my blog.
The scale of the gauge should be 30 but still the pressure appears very low.
Agreed.
Spoke to a friend and long time diesel mechanic tonight. He says that pressure there is "good" given the wide range of the gauge, but it going from some pressure to no pressure (at engine start) is not good.
He said that there should be **some** pressure on either side of the filter housing while the engine is running. (most of my research confirms this)
He suspects that there might be a leak prior to the lift pump that will not show a leak under normal circumstances and that putting some pressure in the tank will expose it.
Next goal will be to seal off the vent on the top of the tank, plug the second fuel port, and use a tennis ball with a hole in each end to force some air in the tank and see if a pinhole leak in the supply line will expose itself. 5-10 lbs should do it (if possible) and hopefully I'll be able to see the pressure at the filter housing showing a complete circuit.
Another though is the possibility that the fuel pump is shutting off when the engine starts. After testing the tank I'll hook up a meter and see if the pump is getting stable voltage while the engine is running.
The only other thing I can think of is a bad pressure relief valve that doesn't allow pressure to build up. (VP44?) That doesn't make much sense though as it is clearly shown during a bump start that there IS pressure.
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