M939A2 Adjustable return fuel check valve.

[maccus]

Got done with the 4th parade today so I got back to the truck fix. Replaced all fittings/hoses/and the first fuel filter holder and a good CAT filter installed. Also added the ball valve directly to the input of the filter holder. Will wait a few days and see if I did good or what.

 

[maccus]

It has been 7 or 8 days since I last tried to start the truck. Turned on the ball valve and started the engine. Blew a little smoke for about 20 seconds or so and then went into a good smooth fast idle (I use 900 for fast idle). Ran very well and did not have to prime. I am going to call it a fix. Glad to get done with monkeying with the truck.

The last things I did (post before this one) did something that removed the problem. Were I to guess I would say that the new filter holder/filter did the trick.

 

[RobertoGatos]

Just wanted to post a follow up. The check valves helped my hard starting trucks quiet a bit. Also, when you order 3 or more valves on the Tork site, the price drops down to 45 a pop.

 

[sandcobra164]

My truck doesn't have this problem but I like the ball valve. That's an Anti-Theft device to someone who doesn't know what they're looking at.

 

[SETOYOTA]

So where does this valve go?

 

[infidel got me]

starting issue

I had the same problem with my923a2. I ran through all the tests ( pressurizing tank, checking lines, vents, etc.) It would start right up sometimes, sometimes it wouldn't start after shutdown and only sitting 10 minutes. It was really frustrating.
I thought it maybe a bad ip. I talked to a buddy of mine and he said it sounded like a bad lift pump. I called napa for a price $290-ouch. So, I called my ford dealer for a cummins lift pump price $90. What the h***, what a difference in price, so I got it. I figured for $90 I had nothing to loose. That was over a year ago and never had another starting issue yet. My right thumb is still bigger than the left one ( from priming this thing) lol . Hope this helps.

 

[idbankrman]

I pulled out what I think is my return fuel check valve. It is towards the forward end of the pump with a fuel hose attached to it that goes straight down and then behind the frame rail of the truck. It seems to have no guts and really has no valve in it? It has a small bolt in the end of it that is shaped somewhat like a cone inside but really its not doing anything to block return fuel. So Im not sure Im taking out the right part. I did look this up in the TMs in two places. In the parts and tools manual it is called a check valve. In another diagram I found its not a check valve. So what gives? Im seriously confused. Can anybody confirm that Im looking at the right part? Also is it possible the guts of my valve headed for the fuel tank?

 

[idbankrman]

Ok I've confirmed that I have been examining the right part on the injection pump (IP. I didn't think the truck would run without this valve at least providing some back pressure to the IP?

 

[tractors0130]

I had the same problem with my923a2. I ran through all the tests ( pressurizing tank, checking lines, vents, etc.) It would start right up sometimes, sometimes it wouldn't start after shutdown and only sitting 10 minutes. It was really frustrating.
I thought it maybe a bad ip. I talked to a buddy of mine and he said it sounded like a bad lift pump. I called napa for a price $290-ouch. So, I called my ford dealer for a cummins lift pump price $90. What the h***, what a difference in price, so I got it. I figured for $90 I had nothing to loose. That was over a year ago and never had another starting issue yet. My right thumb is still bigger than the left one ( from priming this thing) lol . Hope this helps.

I only paid $52 for a few Cummins lift pump from the dealer, someone is sure marking them up.

 

[infidel got me]

Tractors0130--- don't forget I live in Floridaduh-- the prices are highhhhhh and so are most of the people!!!

 

[Coffey1]

Can someone show me in a picture where this check valve is
Thanks
Ken

 

[idbankrman]

Look at the Parts and Tools Volume 1 figure 58. It's part number 1 in the figure. The manual is TM 9-2320-272-24P-1 Page 0059-2 03/15/2011 Rel(1. root(plwp) wpno(R00059)

 

[idbankrman]

I put the Torks OFV020 check valve on my truck after finding the check valve installed on the truck without any guts ie just a straight through hole. It didn't make any difference at all. Truck still loses prime after 24 hours and doesn't run any different. So I'm still looking for the culprit.

 

[idbankrman]

I also tried a new lift pump ( no help there) but I only paid $56 from Highway and Heavy Parts online. I also changed the canister filter gasket and O ring as well as the Schrader valve on top of the filter canister.

 

[MtnSnow]

If you are still losing prime I would say you need to pull the fuel tank feed line and check the solder joint (can also do this on the return line) They are known to crack & then you suck air/lose prime. I actually had the pickup tube completely fall out of the joint while driving down the highway on one of my trucks.

 

[Tornadogt]

It has been mentioned, but Selector valves on trucks with twin tanks (Wreckers,Tractors,Dump trucks) is a common place to suck air and cause this problem..

 

[Coffey1]

I pulled my check valve on front of ip return line and it looked good shiny ball good spring. I replaced lift pump due to leak around plunger but still loses prime overnight not so bad that I have to bleed it primes itself after I crank it for awhile going to try out o ring on top of fuel canster.
Then the pick up tube.

I had to prime truck one morning drove over to Andy house around 45min drive.
Got there shut truck down then started it move closed to shop to weld flange onto muffler to put stack back on.
So we decided to pressure the tank and look for leaks found none but it caused the truck to lose prime why would it do that.

 

[Cape Coastie]

MtnSnow, aka Mike, described my issue to a tee. I have the NHC250 and it kept losing prime. Finally pulled the pickup tube in the tank and with a slight touch the tube fell out of the fitting. Glad it didn't happen while driving the truck. Resoldered the tube to the fitting and the problem was solved. No more priming and the truck starts and actually runs better. No more sucking air I believe.

 

[maccus]

What I finally did on my M931A2 after chasing the loss of prime problem for way to long was to shotgun the fuel delivery source. I replaced everything from the tank to the engine block. Lines, fuel filter and filter holder. Added a ball valve also. You can read more in post #21 which includes pictures

Absolutely no problems since the shotgun procedure.

 

[Plane Fast]

I also tried a new lift pump ( no help there) but I only paid $56 from Highway and Heavy Parts online. I also changed the canister filter gasket and O ring as well as the Schrader valve on top of the filter canister.

Do you have the part number highway and heavy parts uses for the lift pump?
Thanks