ip maybe?

[77_Jimmy]

my m1008 started doing something odd lately. at speeds under 45 no issues. over 45 and engine under a load all is fine . but when i take my foot off the pedal to coast at speeds over 45 motor starts to surge kinda like its running out of fuel. starts right up, the problem is worse the cooler the air temp is.

 

[Cucvnut]

Black text hard to read, please change it. I would check your lift pump.

 

[77_Jimmy]

lift pump and fuel fiter are new.

 

[K9Vic]

Take the top cover off of your IP and inspect for small plastic fragments in the fuel. If you have them your IP is the issue, if not it is likely something else.

Use this video as a guide to take the cover off, you only need to watch the first 1:30 and again from 3:35 to put the cover back on. (Warning, there are a few cuss words, but this video is in HD and better to see)
https://www.youtube.com/watch?v=sRizT_GZOSE

Picture #1 Good


Picture #2 Bad

 

[77_Jimmy]

​wow , thanks.

 

[Keith_J]

The plastic fragments are from the vanes in the fuel pump which generate the intermediate case pressure. This case pressure is how the injection pump varies the injected quantity. Higher pressure means greater injection per stroke which means more torque.

When the vane pump fails, the lower case pressure means less injected quantity. No pressure means no injection which means no power.

As in all mechanical injection systems, there is a mechanical governor. This is a variable speed governor, the variation depends on the accelerator pedal. When the vane pump is failing, the governor will change the injected quantity to keep the engine speed within the requested range but it cannot, this is what creates surge.