I have a 92 cummins with a p pump. i want to get a little more power out of the engine. just doesn't seem like it is running out like it should. it doesn't like any type of hill, it will actually lose 5-10 mph on a small incline. would turning the fuel pin help? or replace the pin and diaphram.

 

It sounds like you have a VE pump which is what came on these trucks. You won't see a top end gain from a fuel pin without increasing the amount of fuel available. This can be done with the fuel screw on the back of the pump. There is a ton of info on free mods you can do to these trucks that will have no problem keeping another 5 10 or 15mph.

 

Is the truck auto or manual? If your loosing that much speed and depending on the hill, your transmission coupling( torque converter/ clutch) might be the issue. Are you loosing rpms or just speed?

 

I am confused. I broke out my B series 91-94 cummins book and it says its a p7100 pump. I do know its not a rotory pump. i am losing rpms and mph. its like it just doesnt want to pull. also it is an allison AT545 automatic tranny. tranmission seems be fine and shifts fine. It takes off good but it doesnt like 45mph and up. Thanks for the help.

 

its definitely a ve pump. p pumps dont have fuel pins anyway. 1989-1993 was the ve rotary injection pump and 1994-1998 were p pumps.

 

Ya know he could have a ppump. With this added info of the allison auto, this could be a frankenstein truck. On a ppump the fuel plate acts as the fuel pin on a rotary pump. The star wheel adjustment is how much fuel the pump delivers in conjunction with boost. ppumps will give you more "free" power than a VE. Try the 94- 98.5 section. they will give you all the info you need to get a little bop in your step!

 

there was someone on here with a bluebird bus with a 91 cummins an allison transmission and a p-pump.

 

It is a p pump on a first gen. I posted on 2nd and it seems like no one wants to help. So I don't know a lot about them and need some help to turn this up just a little. Thanks.

 

The transmission is what's killing ya... It's a non lockup 4 spd with 1:1 ratio. What kind of rpms are you seeing? What gears are in the truck?

 

Have you done any upgrades?