Community Forums

Jon_C · 09-12-2019, 11:58 AM

I have a fuel pressure gauge right at the inlet to my injection pump VP44. At idle i have my raptor lift pump set at 20 psig. With fresh filters and engine pulling grades pressure drops to around 16psi.

After a year the pressure was dropping to 12psi under load. Even tho this is still ok, i decided to change and inspect the old filters.

The 10 micron filter is the cardboard colored filter thats only dirty near the bottom. The 2 micron filter On the motor just before the injection pump is the other one with the hole cut in it.

The 2 micron filter was the culprit, the outer media supposed to be white was working its way to black.
I cleaned a portion of it to make sure and laid it next to a dirty piece that can be seen in pic.

So my takeaway is the 2 micron will need service possibly twice as often as the 10 But i may just change both yearly unless i get a bad batch of fuel.

And i pressurized my fuel tank with air thru the vent hose to force fuel and bleed all air out thru a hose fitting I connect to the downstream side of the 2 micron filter. I cycled the lift pump probably 50 times first and never got it to pickup fuel.

Next time im thinking ill just fill each new filter with ATF from a new bottle that should be easier.

Ray,IN · 09-12-2019, 01:05 PM

Automatic Transmission Fluid/ATF, or motor oil are NOT designed to be burned in an engine, in fact it is formulated to withstand high temperatures; then there is the issue of unknown additives which may damage the pump and/or injector seals.

Simply carry a bottle of diesel fuel for this purpose.

Jon_C · 09-12-2019, 01:31 PM

Ok thanks Ray i know a fella who ran atf and even used motor oil in his truck mixed with fuel but I didn’t know it would cause damage.

Ivylog · 09-12-2019, 03:54 PM

Guess I’m confused??? Cycling the key 50 times is 25 minutes...lift pump runs aprox 30 seconds assuming you leave the key on that long?

twinboat · 09-12-2019, 04:00 PM

I would check the engine fuel system specs.

Are you sure you need a 5 micron filter ?

Also, change one filter at a time and run the engine in between to get the air out.

Quote:

Originally Posted by Jon_C

I have a fuel pressure gauge right at the inlet to my injection pump VP44. At idle i have my raptor lift pump set at 20 psig. With fresh filters and engine pulling grades pressure drops to around 16psi.

After a year the pressure was dropping to 12psi under load. Even tho this is still ok, i decided to change and inspect the old filters.

The 10 micron filter is the cardboard colored filter thats only dirty near the bottom. The 2 micron filter On the motor just before the injection pump is the other one with the hole cut in it.

The 2 micron filter was the culprit, the outer media supposed to be white was working its way to black.
I cleaned a portion of it to make sure and laid it next to a dirty piece that can be seen in pic.

So my takeaway is the 2 micron will need service possibly twice as often as the 10 But i may just change both yearly unless i get a bad batch of fuel.

And i pressurized my fuel tank with air thru the vent hose to force fuel and bleed all air out thru a hose fitting I connect to the downstream side of the 2 micron filter. I cycled the lift pump probably 50 times first and never got it to pickup fuel.

Next time im thinking ill just fill each new filter with ATF from a new bottle that should be easier.

153stars · 09-12-2019, 05:18 PM

Mixed 200to 400 to one is different from filling a filter. Many truckers swear aft would clean certain injectors and such on some years of motors at one time or another.
I'd stick to formulated cleaners at specified dilution.
Fill filters with deisal follow directions for post filter change starting.

Jon_C · 09-13-2019, 09:59 AM

Quote:

Originally Posted by Ivylog

Guess I’m confused??? Cycling the key 50 times is 25 minutes...lift pump runs aprox 30 seconds assuming you leave the key on that long?

My pump only runs for a few seconds with key on unless ecm senses engine crank then it runs longer (30 sec i think) and if engine runs pump stays on.

Jon_C · 09-13-2019, 10:10 AM

Quote:

Originally Posted by twinboat

I would check the engine fuel system specs.

Are you sure you need a 5 micron filter ?

Also, change one filter at a time and run the engine in between to get the air out.

Ill check again but im almost certain the manual calls for 10 micron/ 2 micron filter setup.

And even with fully purging the system, she took a bit to fire, and i changed them 1 at a time a few days apart. normally 2 seconds and shes running took about a minute and i was starting to have flashbacks of purging injectors which is a real pain.

My concern is pour filling the 2 micron filter without getting any contaminants as what gets poured in goes straight to the injection pump. Thanks for all the replies!

Ivylog · 09-14-2019, 05:46 AM

A lot of bad info in this thread.

Crasher · 09-14-2019, 07:51 AM

I have all of the filters changed once a year by the same trusted shop. Usually it's the same tech that services it. In six years and 64,000 miles no issues with fuel or oil. I've been buying fuel from FJ most of the time, but will be switching to Loves with the TSD discount. It's just my opinion, but have always felt that the high volume truck stops should have the freshest, cleanest fuel.

Jon_C · 09-14-2019, 08:47 AM

Quote:

Originally Posted by Ivylog

A lot of bad info in this thread.

Kindly let us know what your referring to so we all can learn. Thank you.

Ivylog · 09-15-2019, 09:56 AM

Quote:

Originally Posted by Jon_C

Kindly let us know what your referring to so we all can learn. Thank you.

Fair enough although it’s been a while since I’ve worked on the VP44 system ...sounds like you have been proactive on protecting your injection pump with a Raptor pump and pressure gauge. Yes, not enough fuel pressure is harmful to the VP44 injection pump but it’s in the less than 5 psi range. The EVM should de rate the engine if it’s not getting enough pressure. Cummins wants the 2 micron first and the 10 second. It’s hard to suck fuel through a 10 micron (lift pump between the filters).

Just because a filter has a little black on some of it does not mean it needs changing. Guess it gets down to are you a change every year person (regardless) or based on miles. Not going to hurt changing annually other than your wallet. Granted I have a % power readout so I only change my fuel filters when I cannot maintain 100% power (while on a trip) starting with the 2 micron first because it’s easier on my rig. Would have been easier last week if I had not forgotten my strap filter wrench...had to go 15 miles and buy a $8 one. I usually get 30,000 miles out of fuel filters buying at the cheapest places only. Love GasBuddy, not Love’s or FlyJ.

Usually the lift pump will run 5-6 seconds when turning the key on and closer to 30 seconds if you just bump the start position. 2 minutes of lift pump operation (4 bumps of start) should fill a dry filter, especially if you moved the lift pump closer to the tank.