TBI adj reg

[john spears]

I haven't seen the Summit adjustable fuel pressure regulator for the GM
TBI's, but the stock regulator is very easy to modify without spending any
money.  When these regulators are produced, they are actually adjustable!
Then when the "correct" pressure is set they weld the head of the screw to
the body of the regulator.   What I do to convert them back is to just clamp
it up in a drill press and drill the weld blob back out. Then I take the
screw and use a hacksaw to cut a screwdriver slot in the head, and
reassemble. This gives a pretty decent range of about 10 - 16 psi.  The
newer 454 TBI trucks are already running around 36 psi, so watch out, they
aren't all the same.   I had a 95 454 duallie truck in recently with a
complaint of overheating the exhaust system when pulling his huge 5th wheel
trailer up hills. I raised the full pressure on it from 36 psi  to 42 psi
and he claims the problem is fixed. I don't have any data to back it up so I
can only go by what he says. I would love to ride up one of the hills with
my scanner hooked up and monitor what the O2 voltage is doing, but he'd have
to take me on vacation with him to do that. Hey.....not a bad idea!
I've found fuel pressure to be a handy tuning tool over the years

                John Spears
  Speartech Fuel Injection Systems