What happens when magazine guys get bored on weekends? More power, that's what. We were waiting around for gauges and some other stuff for our '89 Dodge Ram while we tried to think of a cheap way to solve our slipping transmission problem. Then we realized, "Hey, we haven't turned up the rotary pump in this thing yet!" and set to work with simple hand tools to discover how much power we could get out of free injection pump mods. First, we took off the pump top and rotated the diaphragm. This produced a power gain that was just barely noticeable on our test drive. We'd heard the big power boost was in the full fuel screw, so that was next. The screw had a collar on it from the factory to keep us from adjusting it more than about of a turn, so we cranked it all the way in. It definitely felt faster, but there was still no smoke so we knew we could go further.
Although not as glamorous as its big brother, the P7100 injection pump (found on '94-98 Cummins), the VE pump found on '89-'93 Dodges can still be made to produce some good power.
We backed the screw all they way out of the pump and put it in a vise. We used a chisel, a hammer, and a pair of pliers to pry off the stock collar (which is tack-welded on) in order to turn up the fuel more. We were very careful not to damage the screw (too much) when doing this mod; it is a Bosch part--not something we can just run down to the hardware store and get. Once the collar was off, we could turn the screw clockwise for more power. But wait! There's more.
If we turned the screw too far, our engine could go into a "runaway" when it starts. The pump would keep fueling itself once the engine was started and would keep going even if we turned the key off.
Whenever we're messing with the fuel screw, we make sure to have the intake piping into the turbo off, and a 2x4 or something similar to cover the front of the turbo and stall out the engine in case of a runaway. Never, ever try to stall out the engine with a rag or your hand--make sure you have something sturdy that won't get sucked in the turbo. We recommend that you practice it a couple of times to make sure you have the hang of stalling it out quick, before you get to turning the screw.
Our first step was rotating the diaphragm. This is done to give the engine more fuel under boost. First, we took off the banjo-style air line connected to the top of the pump. There will be a couple of washers that like to fall out, so make sure you don't lose any pieces. | 
Next, we took the pump top off using a screwdriver. The diaphragm is spring-loaded, so be careful when you take the pump top off--the diaphragm will want to come with it. | 
When looking at the top of the diaphragm, you'll see a tick mark it in (arrow) noting it's position. Stock is 12 o'clock, or facing the engine. Ours appeared to be set at about 1:30. |
Next, rotate the diaphragm 90 to 120 degrees clockwise. Inside, there is an offset traffic-cone shaped eccentric. Rotating it will move the offset further away from the fueling rod, giving more fuel as boost rises. Make sure not to over tighten the banjo air line when you put everything back together. | 
Our next free pump tweak involves the full fuel screw that is located at the back of the injection pump (arrow). This is where our major gains would come from. With a screwdriver and 13mm wrench, back the screw out of the pump completely so you can take the metal collar off. | 
This is what the fuel screw looks like after it is taken out of the pump. Count the number of turns from where it bottoms out on the collar to where it bottoms out on the screw to see where the "stock" setting is. Ours was about six turns. |