RE:'87 5KTQ performance trouble

[SOUTHERLIN <SOUTHERLIN@aol.com>]

Colin,
About your low boost.  When I first bought my car (87 5KCSTQ) it too would
only give about 1.1 bar. It turned out to be a tired wastgate spring. I think
after years of temperature cycles they get tired.  I stiffened mine up by
finding a spring a the hardware store that fit the inside diameter of the
existing spring and through trial and error I cut it to length so that it
would help the existing spring to giv 1.3-1.4 bar. This is a dangerous
operation since a "helper spring" that is too long will cause overboost and
could damage your engine.  The performance difference was dramatic and I got
hooked on it and ended up doing a S-Knob mod.  I stil have that "helper
spring" installed even with the S-Knob - never had a reason to remove it. 

On your other problems I think you need to first determine if they are
ignition or fuel related. If it is ignition the fault codes should give you a
clue. I do know a bad knock sensor will cause loss of power.  If you think
they are fuel related you need to measure the system, control and residual
fuel pressures. If you don't know these are O.K then you are just shooting in
the dark. After you know your pressures are good then yuo can start looking a
injectors, coldstart valve etc.

Good Luck

Russ
87 5KCSTQ
Littleton, CO