8.3 Cummins - turning up the injection pump

[transit360]

Hi guys,

Does anyone here have any experience with the 8.3 Cummins? To
me, it looks identical to the 5.9 except bigger of course. I'm
wanting to turn up my injection pump to get a little extra juice and
was wondering is someone could pinpoint where and how to turn it up.
I have two matching pusher buses right now and one of them
runs like a scalded dog and the other one's a slug in comparison.
Both get the same fuel mileage for the most part (around 7-8mpg).
Both have new fuel and air filters and clean diesel, so I'm down to
try and juice up the pump.
The one that has more power also smokes a little more, with a
more detectable smell of diesel than the other from the extra fuel,
so I'm thinking that someone has already turned up the pump on the
faster bus. All specs as far as temp, oil press, rear axle, etc are
the same, which is why I want to try the injection pump next. Any
suggestions? I'm sure it's simple but I always like to ask anyone's
experience.

Thanks,
Steve
http://www.360partybus.com
2 QBRE Bluebird 8.3 partybuses