Injector Pump Issue

[LPopowski]

MY FRIEND'S 1990 250 AUTO DOES NOT WANT TO RUN @950 RPM. IT IDLES, ACCELERATES AND GOES DOWN THE ROAD FINE. THE ISSUE IS COMMING OFF OF IDLE IT STUMBLES AT 950 RPM. ONCE PAST IT, ALL IS FINE. TRY HOLDING 950 RPM IN PARK IT FALLS OFF A BIT THEN COMES BACK THEN FALLS



DOES SOMEONE KNOW WHAT TO LOOK FOR?

THANKS LES P













1986 CTD 350; 2) 1989 ctd 350 1) 1991 ctd 350

 

[JStokes]

Broken return spring?

?????? This may be the problem.

 

[LPopowski]

Thanks; I Will Look.

Les P.

 

[Don Tanklage]

maybe the lift pump is going?



ya know, pumps enough for idle (barely)



cant supply motors demands at 1000 rpm



but once r's get up it can keep up (barely)

 

[dpuckett]

I put my vote in for spring issues or the governor sticking inside the pump. You know, pulls to 950, hnags up, then once it gets enough fuel past that point, it does fine.



Check your lift pump pressure going down the road. Plumb a boost gauge into a 1/8NPT tapped banjo bolt for the fuel supply line after the filter. While you're at it, change the filter. I cant get 10K on one with local fuel.



DP

 

[LPopowski]

We Started With Looking For A Broken Spring. While He Was In The Cab Holding The Peddle At Aprox 950 Rpm, This Is The Rpm That The Engine Surges And The Pump Vibrates More Than Other Rpms. I Pushed Hard Down And To The Side Twards The Block On The Shaft On Top Of The Injector Pump The Surging Would Quit.

Is There A Servicable Bushing On The Shaft?

Thanks Les P.

 

[dpuckett]

Yes, there is a steel upgrade bushing available. You have to remove the top of the pump to replace it, and if it is real bad, you will need a new throttle shaft.



The springs I was referring to were the return springs inside the pump.



DP

 

[LPopowski]

Thanks Dp

Is This Bushing Replacement Some Thing That Can Be Done By A Non Professional In My Garage, Or Do I Have To Take It To The Local Pump Store? I Have Removed A Pump On One My Dodges. I Do All Of My Own Repairs On My Dodge Trucks And Construction Equipment.

Injector Pumps Is Not On My List Of Experences Other Than One 3 Cyl Yanmar Pump That I Dissembled And It Took 2 Days Of Trial To Get The Rack Timed Properly.

My Diesel Engines (13) And Counting Are From The 80's And Early 90's Non Electrical That Run Well With Very Few Issues.

All Said Thanks For The Info.

Les P.