3406c Lacks Power


New member
ve got a 3406c that lacks power. I've been through all the basics. Its getting plenty of fuel to the injection pump. Boost is around 25lbs full throttle. I backed the fuel and torque screws out and they made just a little difference the first 3 turns then that's all the fuel it seems to give. I eliminated the afrc and installed the cover. Low rpm range is good(moderate smoke) but it falls off about mid range on up (almost no smoke). The pump is a 7E-5888
Any suggestions are greatly appreciated!

SN: 8PN12421
Eng model: 3406
Performance spec: 2t-9420
Rated: 425hp@1900
Fuel timing 7.0BTC

Truck Shop

Well-known member
When was the last time that the injector pump has seen any major work or the advance? If it's the one I'm thinking of as a C model there is a plastic arm on the advance that breaks
and it will cause very sluggish response zero power.

Truck Shop