Cat 420D fuel injection pump

I'm working on a Cat 420D loader serial number FDP with a Delphi fuel pump. I was wondering if there is an easy way to bump up the fuel settings for a little more power. Fuel pressure is good , boost does come up ok if you can get the rpm up but it is doggy getting there. no black smoke ever.

you want more power for the loader end? or back end?

If the backhoe, you probably wouldn't notice it without also making adjustments to the torque limiter on the pump. The torque limiter is factory set to engine HP. It won't attempt to pull more power out of the engine just because the engine has more power available.

Turning up the fuel might help with rimpull through the drivetrain, but not the backhoe.

Hydraulic power is ok but it has always been underpowered on the drive most noticeable in 4th gear. I know there are torque converter issues with these but I don't think that's it. I find if you can get it up over 2000 rpm while roading it it will develop about 12 psi boost but as its coming up to speed its lucky to see 6 psi at 1850 rpm. I couldn't find a spec for it on sis or tmi web so if someone knows what peak boost and full load rpm are that would help. Its a perkapillar engine.

Perkapillars ARE THE WORST..
The fuel adjustment is on the "engine side".. BUT..
If the inj. pump has a boost compensator on the top OR side.. the shims can be taken out and you'll notice a SIGNIFACANT improvement.
The BC usually has 2> 5 sided torx screws in the cover.. hard to come by.. unless your "in the biz"..

thepumpguysc said:

Perkapillars ARE THE WORST..
The fuel adjustment is on the "engine side".. BUT..
If the inj. pump has a boost compensator on the top OR side.. the shims can be taken out and you'll notice a SIGNIFACANT improvement.
The BC usually has 2> 5 sided torx screws in the cover.. hard to come by.. unless your "in the biz"..

Click to expand...

Thanks. I don't see a boost compensator or air fuel ratio control.
So when you say it's on the engine side you mean you can adjust it without removing the cover? I thought I remembered something about an Allen screw adjustment near the rear of the pump but I can't see an access plug on this one.

Without a pump # its hard to tell..
I have the Delphi program at hand.. so if you can get the #'s.. I can hook you up..