injection pump check valve

[Zaggnutt]

So I've had some air intrusion issues recurring and I'm going through the fuel system to track them down. I'm getting the start then stall and long crank to restart.

Fuel filter is a little more than half full upon inspection. That is telling me that I have air getting in between filter head and return line to tank. Fairly certain this is leak down as opposed to blockage or air prior to lift pump but I could be wrong. I'm getting no surging, stalling while running.

O ring kit from Mel was done a while back.
Fuel heater o ring done.
Olives done.
Replaced o ring in the check valve pictured, but it appears my mechanic lied to me about it's "diesel fuel rated" characteristics. It's been on there for a month and its' deteriorated already...
Just completed manual valves with new rubber lines for everything except main intake line and return line to rear tank.

So the return fitting / check valve on top of the IP... I guess I'm looking for clarification on its purpose. I removed the two fittings....

You must be registered for see images attach

The brass barb has the tapered threads which I don't like so I am going to seal them with riot's patented elephant snot or something but in the meantime I blew through the check valve with the clear plastic or glass piece (mouth to fitting) and could get air through both ways.... out from the ip side more than back through towards ip.

1. What is the purpose of this fitting?
2. Does it matter that I can get air through it either way?

Thank you.

 

[OLDBULL8]

IP liquid fuel pressure opens the check valve to allow fuel to the return line which fills the injectors, when the IP pressure drops with engine shut down the spring loaded check ball closes (seats) preventing any fuel in the return line going back into the IP, hence sealing the return line from draining to tank. Been a long time since I had one apart, but IIRC it has a rubber seat.

Edit: I think riot's snot is for making gaskets. Use teflon gas line paste sealer.

 

[Zaggnutt]

Okay, thank you. That makes sense. Heres another pic of the fitting...
Just inside the top is a clear piece of material covering the hole... This is what I was blowing through...

You must be registered for see images attach

I noticed the chamber where the ip check needle is empty so there is a little drain hole at the bottom of that chamber to recycle fuel? So would it matter then if this check fitting is not "checking"?

I'm trying to understand the purpose of this fitting. Especially before I goop it up and reinstall it....

 

[Zaggnutt]

Edit: I think riot's snot is for making gaskets. Use teflon gas line paste sealer.

Will do. Just happened to have some for the manual valves. Thanks again.

 

[rockbender]

I recently e-mailed Conestoga's shop with a very similar question about that valve purpose and got this response:
"The pressurizing valve isn't really a check valve, although it has most of the characteristics of one. Its main purpose is to create a specific pressure in the governor housing of the injection pump while the engine is running. The ball valve is raised off of its seat by the cold start advance solenoid which changes the housing pressure allowing movement of the advance piston."
Hope this helps.

 

[Zaggnutt]

Okay, thank you. I guess the real question I'm trying to answer here is: Is it working properly? That's the purpose for trying to figure out what it does. Thanks.

 

[OLDBULL8]

I recently e-mailed Conestoga's shop with a very similar question about that valve purpose and got this response:
"The pressurizing valve isn't really a check valve, although it has most of the characteristics of one. Its main purpose is to create a specific pressure in the governor housing of the injection pump while the engine is running. The ball valve is raised off of its seat by the cold start advance solenoid which changes the housing pressure allowing movement of the advance piston."
Hope this helps.

I agree with that. But if it doesn't seat (close) tight, the slightest air intrusion down stream will cause a drain from that point.
I didn't know you wanted a technical explanation on what it does, I was trying to answer for an air intrusion.

 

[icanfixall]

That check valve on top of the pump must function. You can test it by adding fuel to it from the top side where the brass fitting connects. If any fuel leaks thru it the valve is shot. any good injection pump repair shop will have one or any gm 6.2 or 6.5 or any idi in a wrecking yard will do. That o ring is important too under the fitting check valve. It must make a seal. That brass barbed fitting is a pipe thread and must be a tapered thread to seal on the threads too. some thread sealant can be used too but not teflon tape ever.

 

[Zaggnutt]

That check valve on top of the pump must function. You can test it by adding fuel to it from the top side where the brass fitting connects. If any fuel leaks thru it the valve is shot. any good injection pump repair shop will have one or any gm 6.2 or 6.5 or any idi in a wrecking yard will do. That o ring is important too under the fitting check valve. It must make a seal. That brass barbed fitting is a pipe thread and must be a tapered thread to seal on the threads too. some thread sealant can be used too but not teflon tape ever.

Ahhh okay. Now we're gettin' somewhere! I guess the question I needed to ask was: "How do I test it?" I apologize if I was being vague. Thanks very much!

 

[Zaggnutt]

I agree with that. But if it doesn't seat (close) tight, the slightest air intrusion down stream will cause a drain from that point.
I didn't know you wanted a technical explanation on what it does, I was trying to answer for an air intrusion.

I was asking for both really. I need to understand how these components work so I know what they do and why, but yeah I need to solve a problem too. Sorry for not being clear. Thanks for your help.

 

[icanfixall]

Well the function is simple. When you energize the shutoff solenoid you feel and hear the click. Well thats the solenoid pushing a lever against this pin on the check vale opening it. now fuel can flow thru the injection pump top cover. Now shut off the power to that solenoid by pulling the ire or turning off the ignition switch and its going to close stopping the fuel flow out the top of the pump. That kills the engine. Why it kills the engine is not something I know but suspect it has to do with a pressure buildup in the pump on 2 sides of the fuel system. Hope thats clear.. I kind of made it up as I went along....

 

[Ugly Moosling]

Well the function is simple. When you energize the shutoff solenoid you feel and hear the click. Well thats the solenoid pushing a lever against this pin on the check vale opening it. now fuel can flow thru the injection pump top cover. Now shut off the power to that solenoid by pulling the ire or turning off the ignition switch and its going to close stopping the fuel flow out the top of the pump. That kills the engine. Why it kills the engine is not something I know but suspect it has to do with a pressure buildup in the pump on 2 sides of the fuel system. Hope thats clear.. I kind of made it up as I went along....

This is not correct, the solenoid that opens and closes this valve is the cold start advance solenoid not the shut off solenoid. The majority of the time this solenoid is not energized while the engine is running. The shut off solenoid is the larger solenoid with the arm on it that pushes on the governor linkage in the injection pump.

I recently e-mailed Conestoga's shop with a very similar question about that valve purpose and got this response:
"The pressurizing valve isn't really a check valve, although it has most of the characteristics of one. Its main purpose is to create a specific pressure in the governor housing of the injection pump while the engine is running. The ball valve is raised off of its seat by the cold start advance solenoid which changes the housing pressure allowing movement of the advance piston."
Hope this helps.

This is the correct info regarding this valve.

 

[OLDBULL8]

Enough is enough. I see a ******* match coming on.

I suggest this thread be CLOSED.

 

[ksingltn]

seems like a civil discussion at this point. I would leave her be. I too would like to know more about this.

 

[Zaggnutt]

Sealed and installed check and brass elbow. Still getting leak down in filter. Looks like I have at least one leaky injector cap since replacing return hose to #8 injector. Will report.

EDIT: The hose from the check valve to injector return line was putting vertical pressure on the cap. Turned brass fitting and no leaks so far. Still some air gettin in the system but after sitting for 3 hours truck starts right off, chuffs for about a minute and then levels out. I will check to see if it starts and stays running in the morning. Thanks for the info, gentlemen.