Airdog quality

[diesel4life]

Anybody ever have any EXCESSIVE fuel pressure issues? It seems that whenever we see sub zero temps my fuel pressure will slowly but steadily climb up to about 26-27 psi before "something" gives way and the pressure just drops back to normal pressures and runs perfect. It has happened 7 or 8 times this winter and every time its been below zero out. I can't see how temps could cause the spring/ball to freeze, if in deed they were frozen that would mean I have moisture in the fuel system and would have bigger problems.

Any thoughts?

[Mopar1973Man]

So is that groove in the ball where the spring had stretched around the ball? Or from being pushed into the pump housing?

 

I would say pump housing marks. Too wide to be spring marks.

[Mopar1973Man]

Anybody ever have any EXCESSIVE fuel pressure issues? It seems that whenever we see sub zero temps my fuel pressure will slowly but steadily climb up to about 26-27 psi before "something" gives way and the pressure just drops back to normal pressures and runs perfect. It has happened 7 or 8 times this winter and every time its been below zero out. I can't see how temps could cause the spring/ball to freeze, if in deed they were frozen that would mean I have moisture in the fuel system and would have bigger problems.

Any thoughts?

 

Possibly a kinked return hose?

 

Possibly a check ball is sticking?

[rancherman]

I'd say it's  where  the  ball  strikes the housing.   over and over and over... 

 

Those  impulses  that  destroy the  FP  gauge  are  most  definitely    making the way  back to this  ball..     

[diesel4life]

Possibly a kinked return hose?

 

Possibly a check ball is sticking?

Possibly a kinked return hose?

 

Possibly a check ball is sticking?

Logic says it has to have something to do with the check ball/spring, I just don't understand how cold temps could affect those parts. I first had this problem back in December when we had a week of sub zero weather, and every time I ran the truck after a good cold soak the pressure would slowly climb up to the mid-upper 20s and then drop to normal pressures. Once things were warmed up a bit I never had the problem again. I even drove to upstate NY where it was -20 and the issue never repeated itself but I never shut the truck off either. Then the weather warmed back up and the problem went away until this morning when the temps were about -7 and the problem came back. I'm going to pull the spring and ball and have a look but I don't expect any problems, I just replaced both over the summer.

[Dieselfuture]

About groove in ball, I believe it's from the spring but I could be wrong both surfaces are about same, spring and housing. I did talk more with fass today and they have oring kit for putting motor on other than that not sure. Fass was nice enough to me to day they send out new ball and spring after I told them I had issues with psi spikes and I moved ball and modified spring, and problem went away. They said its common problem and sometimes it gets bad enough where pressure will change as much as 10 psi. So yeah I would say modifying that spring somehow helps, and new surface on ball to seal against. I think they need to redesign it an do something like valve and seat like in a head. It will be metal against metal and if done right will last a long time.

[Dieselfuture]

Logic says it has to have something to do with the check ball/spring, I just don't understand how cold temps could affect those parts. I first had this problem back in December when we had a week of sub zero weather, and every time I ran the truck after a good cold soak the pressure would slowly climb up to the mid-upper 20s and then drop to normal pressures. Once things were warmed up a bit I never had the problem again. I even drove to upstate NY where it was -20 and the issue never repeated itself but I never shut the truck off either. Then the weather warmed back up and the problem went away until this morning when the temps were about -7 and the problem came back. I'm going to pull the spring and ball and have a look but I don't expect any problems, I just replaced both over the summer.

I think you were close to jelling and viscosity of fuel was higher, so pump has gear rotor to pump fuel so it's kind of positive displacement. As fuel got thinker pump keeps pumping but can't get through lines fast enough so pressure goes up, that would be more likely especially if your return from AD to tank was reduced less than 1/2". Like if you're using fitting on module that is 3/8 for return. I had similar issues until I switched to 1/2" all around, I never had problem with return to filler neck but I had problem sucking air at 1/3 of tank if I slam brakes or get on it, so I switched to module in and out.

[diesel4life]

If fuel gels, you lose volume and therefore pressure.

The first place fuel will gel is in the filters, and your gauge will reflect that.

Edited February 4, 2015 by diesel4life

[rancherman]

I can't see how a groove on the backside of the ball (caused by the  ring on the spring)  would cause it to  hang up.     I noticed  the ball in your pic being  almost black..   is it really that color in 'person'?

 

I can  tell you however...  immediately behind  any   pressure reduction  device   (this  particular  ball and spring)  is  a  prime spot  for   Ice  to form and grow.   I've seen RUSTED springs behind  these  kind of   ball valves  in  a lot of different   fuel systems.   Last time I checked,  diesel fuel  isn't that corrosive!    The  tiny wire spiral  would then  make a perfect  foothold for  h20 moles to  seed and grow  upon. 

 

They could very easily then  get  built up  enough to   really hang up the ball from the backside..  causing the  spike in  pressure.

[Dieselfuture]

If fuel gels, you lose volume and therefore pressure.

The first place fuel will gel is in the filters, and your gauge will reflect that.

You're probably right I was just brain storming, I would still check that ball out. Edited February 4, 2015 by Dieselfuture

[Dieselfuture]

I can't see how a groove on the backside of the ball (caused by the ring on the spring) would cause it to hang up. I noticed the ball in your pic being almost black.. is it really that color in 'person'?

I can tell you however... immediately behind any pressure reduction device (this particular ball and spring) is a prime spot for Ice to form and grow. I've seen RUSTED springs behind these kind of ball valves in a lot of different fuel systems. Last time I checked, diesel fuel isn't that corrosive! The tiny wire spiral would then make a perfect foothold for h20 moles to seed and grow upon.

They could very easily then get built up enough to really hang up the ball from the backside.. causing the spike in pressure.

That ball is black in color, and it's viton, also found some orings today that are viton one was dark greenish color and the other was black. I used to think viton was brown but not so. Also stopped at CAT and looked at their chart, it said nitrile or viton for diesel fuel.

[rancherman]

Just curious..    Now that I  know  the  ball isn't  steel!! 

 

we see    claims today  that  'this or that'  is   bio diesel  compatible..           What exactly is  IN  biodiesel  that  is  detrimental???   and  what  materials  are getting  affected  by it?

 

Viton and  Nitrile  been around   a long time,  with  great  results in  'normal'   diesel..      Is  this  one of  the   materials   talked about?

[Dieselfuture]

Just curious.. Now that I know the ball isn't steel!!

we see claims today that 'this or that' is bio diesel compatible.. What exactly is IN biodiesel that is detrimental??? and what materials are getting affected by it?

Viton and Nitrile been around a long time, with great results in 'normal' diesel.. Is this one of the materials talked about?

That's what I'm trying to figure out too, bio is vegi or some food oil, you would think that diesel would be more corrosive to rubber materials, maybe it's additives that's in it that make it eat regular diesel hoses and orings. On that ball if it was stell it would bit up aluminum housing that it's in, I thought why not make it like an intake valve on engine with harden seat and somewhat lose gide, and put same spring in front or even on back side, should last for years. IMO. I bet someone can even make it so it fits in the same hole, screw right in, might stick out a bit more. And on that seal they should use one that rubs on it self and not on the tiny shaft, that way seal wears out but shaft and housing don't. Edited February 4, 2015 by Dieselfuture

[Dieselfuture]

speaking of bio, this is 5-20% bio look at all ice particles in it. in regular diesel I never drained ice particles out of separator.

[rancherman]

well,  in  homemade  diesel (using  restaurant  grease)    LYE  is used to  break down the fatty chains..   which  keeps  them  homogenized.      Perhaps   it's  this  process that  adds  the  caustic effect to  some   materials?

 

also known to  readily absorb water..

Edited February 5, 2015 by rancherman

[Dieselfuture]

I found some orings for between  base plate and motor CAT #'s  small 8L2746 $2    big 5K0227 4$  I believe they are both Viton. Also found seal at local BDI bearings 13$ and bearings 13$ each. Will post some pictures when I get them. That should be all unless other oring look bad and need changing. Honestly I think all orings could be reused.

[cbrew]

I would say pump housing marks. Too wide to be spring marks.

 

I have been away on Business and was unable to reply but here is some observations and experiences from manufacturing ball check valves, and yes, this is a spring biased ball check valve. 

it is common practice after machining the seat, to use a ball, pounce and hammer to create the seat on the valve body, during this process, the ball will have a mark just as it is pictured, it should be discarded and replaced with a new ball, then assembled and tested. 

i would bet, this ball was not discarded. 

 

another note to consider, these pumps that are capable of supplying fuel up to 400 to 600 HP, that said, the ball should never see the seat while running under normal conditions, the ball will float just off the seat as it is maintaining the set pressure, 

 

 

just some thoughts of someone that has machined these type of products 

[rancherman]

This isn't a hard steel ball.   Nitrile or  Viton material.       They better not  try using it to  'form the seat'!!

[cbrew]

This isn't a hard steel ball.   Nitrile or  Viton material.       They better not  try using it to  'form the seat'!!

ok, that is a different ball of wax, did you look in the bore at the seat, being soft, it most not be a sharp edge. 

[Dieselfuture]

ok, that is a different ball of wax, did you look in the bore at the seat, being soft, it most not be a sharp edge. 

I looked at bore of fass and it looks like machined aluminum, no rubber in side. and here is a picture of a ball that has two groves in it, one from being shipped to me and the other from running it for 2 days. And i confirm that the groove is from the seat and not the spring.