Injection pump de-fuelling rpm

Another thread got to talking about @what rpm a pump begins to de-fuel. I got a bad video of mine this morning. It will do this in every gear and any load.

Normal or not?

Normal

our injection pumps have a built in governor system that controls fuel flow dependant on load and as we get up in RPM's around 3000rpms-3200rpm's they start defueling heavily there are some injection pumps set to defuel at 2800rpm's but those were usually designed for fleet vehicles like UPS / fedex / mail service you can adjust these slightly if needed but you got to be carefull a small change only otherwise can throw your fueling curve way off and make it run rough or hard to start if you take injection pump cover off that is on top with 3 bolts 5/16 and under there use a 1/2 wrench there is a threaded bolt / nut in center turn it to passenger side 1-2 turns this will raise the max RPM before defueling but remember be carefull of any dirt getting in there and also only do a small change of this otherwise can really make things run weird.

I want to also point out changing this changes idle speed also another thing to note if you turn it keep track of how many times and such if you got around 3-4 turns ( aka movements of the wrench till need to repposition) on it if is a 2800rpm set one it will now rev to around 3200-3300 rpm's also if you crank this to many times it will override the built in governing system and literally roll coal hard with slightest movement of the fuel pedal.

I tend to go 2 wrench position changes on a already 3200rpm set unit to get me a little extra oomph and i max my fuel screw on a turbo 7.3 IP in the side of IP. I have a custom HX50 turbo that flows enough air and allows enough airflow pre turbo spool to let my engine not heavily coal roll unless I want it to but let me tell you when the turbo comes on it comes on hard and at 20psi its pretty beastly but that truck and motor is highly modified and alot of work in it. I dynoed it a while back at like 325hp and 680ftlb of torgue at the rear wheels and I wasnt pushing it hard between 1/2 and 3/4 throttle so yeah its a monster for a old international harvester IDI.

I have what appears to be a de-fueling situation at 2000 rpm. I don’t know if it could be governor related or housing pressure related or what. I’ve seen other mention of “flat spot” on hete. Any ideas for me? It’s a reman pump that somehow got a Cat Reman plate on it, untampered with (tho i don’t see paint on the cap fasteners)

Vern said:

I have what appears to be a de-fueling situation at 2000 rpm. I don’t know if it could be governor related or housing pressure related or what. I’ve seen other mention of “flat spot” on hete. Any ideas for me? It’s a reman pump that somehow got a Cat Reman plate on it, untampered with (tho i don’t see paint on the cap fasteners)

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Make sure cable hasn’t stretched and you’re getting wot

Okay Happens irrespective of accelerator position, in acceleration mode

Thewespaul said:

stretch

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and also under deceleration with accelerator partly depressed

Not sure I follow.. acceleration mode?