Injection Pump Stumble

[RAYZER]

So i just completed a 900 mile round trip with the deuce tractor with new head gaskets installed in between!
She has always run top notch with no fuel systems issues.
Primary filter was changed before the trip and normal fuel return splash in the tank so i don't believe any filters are clogged, i do run some filtered wmo.
After the head gaskets she ran great and was void of the issue that I'm now having.
About 150 miles into my trip back from Ga (pulling the Taj)
I made a pit stop and noticed that when completely letting off of the throttle, instead of stopping at 800 rpm's where the idle is set, she wants to stumble past and down to 400 or 500 rpm's and quickly bounce back to 800 rpm, sometimes after running hard shutting down completely, then having to pull the throttle cable out some to get her to start (when hot).
Otherwise she starts right up and idles normal, if i come down slow off the throttle, say from 1500 rpm there's no stumble.
I did set the idle screw up to 850 rpm and that seemed to help slightly with the stumble.
Pulled the IP side cover and fdc to have a look inside, nothing loose, off or broken in there, compared it to another pump i have and all looks and feels normal, no broken pieces in the bottom, no noticeable loss of performance.

Has anyone exsperiance this particular issue and can lend some insight?

 

[doghead]

Those are the beginning indications of a worn out HH.

 

[gimpyrobb]

It kinda sounds like a governor issue(from what I have read here on SS), but if you have a spare pump, I'd carry it with you. I take one with me where ever I go.

 

[RAYZER]

I Was hoping It might be an adjustment!

 

[Jeepsinker]

Mine used to do this from time to time. It usually clears up after changing the secondaries and just driving. Try mixing some more clean fuel in with the mix.... Like a lot more clean fuel. Pour in a couple quarts of xylene.

 

[RAYZER]

Will do!

 

[welldigger]

Mine did the exact same thing. If I stayed on the throttle I had no problems. Push the clutch in to shift and it would surge. Took my ip off and had it rebuilt. Aside from it leaking everywhere a governor weight had broken off causing the surging.

 

[Tow4]

Did you read the tm?

 

[RAYZER]

Did you read the tm?

Read what??

 

[Tow4]

Did you read the tm?

Read what??

Oops! My bad, did you have doghead read the tm for you and post the appropriate pages?

 

[RAYZER]

It helps to stay on DH's good side!

 

[Tow4]

It helps to stay on DH's good side!

No doubt! You couldn't have fixed your wrecker without him!

 

[RAYZER]

Pulling the injection pump,
Note to self: don't forget to pull the winch drive shaft.

 

[Jeepsinker]

Sorry to hear that you have to go through this now so soon after the head gaskets.

 

[welldigger]

Pulling the injection pump,
Note to self: don't forget to pull the winch drive shaft. View attachment 523478View attachment 523479

Pull a battery terminal if you haven't already so no one can accidentally hit the starter over and throw the engine out of time with the pump.

 

[RAYZER]

Pull a battery terminal if you haven't already so no one can accidentally hit the starter over and throw the engine out of time with the pump.

Absolutely, finding the right stroke is easy enough, but someone hitting the on switch would send fuel down the driveway!

 

[welldigger]

Absolutely, finding the right stroke is easy enough, but someone hitting the on switch would send fuel down the driveway!

That would also be bad.

 

[rustystud]

Pulling the injection pump,
Note to self: don't forget to pull the winch drive shaft. View attachment 523478View attachment 523479

RAYZER, you got a real nice truck there ! I see no rust and lots of good clean paint ! Some trucks the top side is all nice and clean, but underneath it is a rust bucket.

 

[RAYZER]

Thanks rustystud!
She was refurbished and completely painted 3 years ago, looks all shiny underneath now being all oiled up from the recent trip on a blown head gasket!
http://www.steelsoldiers.com/showthread.php?p=925413

 

[RAYZER]

So before starting the teardown I changed fuel filters resulting in no change, figured that.
Also pulled injectors and had them pop tested, all of them (two hole) were in perfect condition and popped at 3500 psi with no leakage!
So now the ip is coming off for further inspection and replaced with a different ip, possibly an lds ip!