Cummins N14 STC Fuel Injection Pump throttle lever not moving much

[Roadoil]

I have a new to me 2003 Cummins N14 STC a non ECM hydroblast pump 475 HP.

Unit has been sitting a few years, the throttle cable appears to be removed and the linkage on the PT pump has maybe 20 degrees movement. It doesn't feel like it's moving anything just slop.

I have not tried to start the engine the motor turns over using big wrench on alternator bolt freely seems to have good compression.

The tag on PT pump matches engine tag 1921.

So thought of removing the 4 bolts that hold the 301523 part and trying to clean it up and maybe free up the pump levers.

I also checked the shut off solenoid the wire broken off applied 12V Dc with power probe no click so I assume that's gummed jammed up as well.

Wanted to get advice if I should partially tear down the pump and try and free it up before I start taking parts off.

 

[Roadoil]

Here is the throttle lever that doesn't have much movement at all.

I have a similar older pump that has a 855 Big Cam has the throttle cable and same linkage on pump with full movement. So obvious difference here.

Obviously the motor would not start or may rev instantly to 3000 rpm with current situation here.

 

[funwithfuel]

To my knowledge, this is your throttle shaft. White arrow. That lever up there, I think is manual shut-down. I'm gonna have to dig up some old books.

 

[crane operator]

Cutaway diagram and picture of a typical truck throttle set up. Electric switch on throttle is for jakes.

 

[Roadoil]

To my knowledge, this is your throttle shaft. White arrow. That lever up there, I think is manual shut-down. I'm gonna have to dig up some old books.

This is how they set up these hydroblasting pumps here is a pic of the 855 engine (RED) with throttle cable connected to same lever.

You can see on pic of this pump the fastener bolt for the cable and the hole where cable mounts.

I see what you are saying but this is different to control the engine rpm manually via cable to change pump pressure and gpm

 

[Roadoil]

Cutaway diagram and picture of a typical truck throttle set up. Electric switch on throttle is for jakes.



View attachment 267656 View attachment 267657

That injection pump is for the on road Celect Plus and Celect that use Can Bus via the ECM to control the throttle.


This is the STC N14 used on Ag Equipment etc that has a manual throttle control no ECM

 

[Roadoil]

What I am wondering is if I take the 4 fasteners that hold this part with the throttle lever on and remove it, try and clean up the gunk or see what's jammed broken does this mess up the calibration ? There was a wire seal tag on the bottom bolt I started removing the fasteners but not all to take this off I just don't want to create more problems if doing so would require calibration and I need to take it to a injection pump shop anyway.

 

[Roadoil]

Cutaway diagram and picture of a typical truck throttle set up. Electric switch on throttle is for jakes.



View attachment 267656 View attachment 267657

Ok I was wrong that looks like a manual throttle control STC N14.

I don't know why they set it up this way on these pumps but here you can see the same linkage with cable on a Big Cam 855. This is another pump I have though this motor in red was locked up due to rusted exhaust letting water in cylinders bought at auction.

But for reference.

Where the throttle arm is attached on the pic you posted neither of my PT pumps allow any movement of that shaft, it's locked up on both.

 

[funwithfuel]

There should be a solid housing with 4 screws and a single ³/¹⁶ stud, that's the fuel s/o solenoid. They only click if there's no fuel. It's really faint. With on-road engines, there would be a manual thumbscrew on the opposite side. If it's there, it will be on the block side by the AFC diaphragm behind the tach drive adapter. You might get a flat blade screwdriver in there. Turn the screw til it stops gently. That will give you manual fuel on. At the fuel inlet fitting, there may be a filter screen. Additionally check the pulse damper, if that plate is cracked, you'll have a hard time pulling prime.
Since that was an industrial application, it may very well be a 24v system. Check starter and alternator tags for verification.

 

[Roadoil]

There should be a solid housing with 4 screws and a single ³/¹⁶ stud, that's the fuel s/o solenoid. They only click if there's no fuel. It's really faint. With on-road engines, there would be a manual thumbscrew on the opposite side. If it's there, it will be on the block side by the AFC diaphragm behind the tach drive adapter. You might get a flat blade screwdriver in there. Turn the screw til it stops gently. That will give you manual fuel on. At the fuel inlet fitting, there may be a filter screen. Additionally check the pulse damper, if that plate is cracked, you'll have a hard time pulling prime.
Since that was an industrial application, it may very well be a 24v system. Check starter and alternator tags for verification.

Here is a pic of the shut off screw on back of solenoid. It doesn't click or move much either.

I will verify on the 24v system.


The main problem now is no movement with the throttle lever. Well it moves a bit but feels like slop in the linkage.

 

[funwithfuel]

Turn that in till she stops.
I would refrain from takin stuff off or pulling stuff apart. That's like a $2k pump. You never know where the geezus part is and where it's gonna jump to or if it's gonna break.

 

[Roadoil]

View attachment 267674
Turn that in till she stops.
I would refrain from takin stuff off or pulling stuff apart. That's like a $2k pump. You never know where the geezus part is and where it's gonna jump to or if it's gonna break.

Ok it's not really moving feels like it's slipping.

Yeah I know it's a rare pump Cummins wants $2900 to rebuild it only option.

I have found a few rebuilders that will overhaul it for $900 but if it's simply gummed up from old fuel that I can free up easily taking that throttle part off etc I'd rather give it a shot first. Lol


Also that back lower bolt holding this pump on looks real fun to get off.

The paint on this pump and N14 was the trend of the time that thick miserable epoxy paint they sprayed everywhere, sensors and fasteners makes removing parts lots of fun.

 

[crane operator]

So your "throttle cable" is in the same area as the normal electrical fuel shut off solenoid is located on a truck version. In this industrial motor, I think what they are doing is locking the standard throttle control, and using a adjustable plunger controlled by your cable, controlling the fuel after the gov. and throttle shaft.

There's a whole series on youtube that truck shop posted up on the pt cummins injector pump and how it works. It really helped me understand what's going on. Its not going to show your "industrial" set up, but if you watch them all, you'll get a idea.

I'm going to guess by the external rust, this thing has been sitting a while, and the last plunger that they are using to neck down the injector fuel by your cable, is stuck shut.

Here's the first video in the series, the other ones are by the same poster, but concentrate on the one that shows the "fuel shut off solenoid" and I think your cable is doing a similar thing - i.e. the pump is locked at full throttle and full pressure pushed all the way to your control, rather than in the trucks where they use variable speed on the lower shaft.

 

[crane operator]

 

[funwithfuel]

Well, I shared my concerns. Good luck to you. Found one on flea bay for 1650 if it fits your CPL

 

[Roadoil]

So your "throttle cable" is in the same area as the normal electrical fuel shut off solenoid is located on a truck version. In this industrial motor, I think what they are doing is locking the standard throttle control, and using a adjustable plunger controlled by your cable, controlling the fuel after the gov. and throttle shaft.

There's a whole series on youtube that truck shop posted up on the pt cummins injector pump and how it works. It really helped me understand what's going on. Its not going to show your "industrial" set up, but if you watch them all, you'll get a idea.

I'm going to guess by the external rust, this thing has been sitting a while, and the last plunger that they are using to neck down the injector fuel by your cable, is stuck shut.

Here's the first video in the series, the other ones are by the same poster, but concentrate on the one that shows the "fuel shut off solenoid" and I think your cable is doing a similar thing - i.e. the pump is locked at full throttle and full pressure pushed all the way to your control, rather than in the trucks where they use variable speed on the lower shaft.

Ok sure I'll check them out. I hope it's not rusted inside just gummed up old fuel. Lol

yeah this linkage part is right next to the shut off solenoid circled

 

[Roadoil]

Well, I shared my concerns. Good luck to you. Found one on flea bay for 1650 if it fits your CPL

Yeah thanks have seen a few on eBay but since this is a rare engine 475 hp the PT pump numbers calibration don't match.

So a pump off eBay would need to be recalibrated to my engine. Might as well try and rebuild mine would be cheaper than buying another unless it's trashed inside.

 

[Roadoil]

I'll hold off talk to some more injection pump rebuilders tomorrow before I start taking parts off let everyone know here what they say.

I appreciate the advice

 

[Tenwheeler]

I have a new to me 2003 Cummins N14 STC a non ECM hydroblast pump 475 HP.

Unit has been sitting a few years, the throttle cable appears to be removed and the linkage on the PT pump has maybe 20 degrees movement. It doesn't feel like it's moving anything just slop.

I have not tried to start the engine the motor turns over using big wrench on alternator bolt freely seems to have good compression.

The tag on PT pump matches engine tag 1921.

So thought of removing the 4 bolts that hold the 301523 part and trying to clean it up and maybe free up the pump levers.

I also checked the shut off solenoid the wire broken off applied 12V Dc with power probe no click so I assume that's gummed jammed up as well.

Wanted to get advice if I should partially tear down the pump and try and free it up before I start taking parts off.

I have a new to me 2003 Cummins N14 STC a non ECM hydroblast pump 475 HP.

Unit has been sitting a few years, the throttle cable appears to be removed and the linkage on the PT pump has maybe 20 degrees movement. It doesn't feel like it's moving anything just slop.

I have not tried to start the engine the motor turns over using big wrench on alternator bolt freely seems to have good compression.

The tag on PT pump matches engine tag 1921.

So thought of removing the 4 bolts that hold the 301523 part and trying to clean it up and maybe free up the pump levers.

I also checked the shut off solenoid the wire broken off applied 12V Dc with power probe no click so I assume that's gummed jammed up as well.

Wanted to get advice if I should partially tear down the pump and try and free it up before I start taking parts off.

 

[Truck Shop]

That PT pump has two governors, one is governed rpm {internal} the other is the load governor on top
of pump with the throttle lever. The fact that engine has set awhile and the high possibility it could have
had bio fuel run in it plus any moisture would collect in bottom of pump. I would have the pump checked.
The throttle does not operate off the lower fuel shaft.