North American Turbocoupe Organization

boost problems
Joey Hager Offline
ok, I recently rebuild the motor in my turbo coupe and before I rebuild it, it had around 14 psi of boost, now that I have rebuild it all I can get is around 10, no more, I would really love to know what the problem is because it seems like it would have a lot more power than what it used to if it would just boost up the same, I didnt take any unnecessary wires or vacuum hoses loose so I dont think it would be that , any suggestions would be greatly appreciated, thanks

88' turbo coupe 3" downpipe into 2.5" one chambered flowmasters, K&N pod filter
88 turbo coupe, black 5-speed all options but leather, K&N cone, 3 in. downpipe, no converter into 2.5 in. one chambered flowmasters, 86' GT stainless tips, gillis boost contoller, 3.73s, 16x8 (knightrider) rims, 2 JL audio 15s in trunk, punch 800

segfaultxr7 Offline
Posting Freak
Is it making any different noises? Check that the bolts holding the turbo together are tight, and of course the IC hoses too. Could the boost control solenoid hoses be hooked up backwards? I don't know if that would cause your symptoms but it would be really easy to do by accident.

You could isolate the problem by temporarily unplugging the wastegate actuator and carefully seeing if it goes past 10 psi. If not it's a boost/exhaust leak, stuck wastegate, or other turbo problem. If it goes higher it's something with the boost control.
88 TC 5-speed

Turbocruiser88 Offline
Senior Member
Make sure that you didn't plug your wastegate lines. The wastegate will open at 10psi automatically if you did so. The other extreme is to leave the line open to the atmosphere and you will get almost uncontrollable boost! You have to be very careful if you like your turbocharger...

Les T.
88 TC - Light Sandalwood/Black 5sp. *RIP* Precision SC-50, A237, Stage 3 clutch, Ported E6/Intakes, 54k motor
94 BMW 540i
92 Saab 900s Vert
82 Stang GT - T-Top, Soon to be 2.3T - that engine shown above!
80 MB 300SD - Turbo Diesel
96 Explorer - 5.0 GT40 AWD, Soon to be turbo'd

Keith Nubel Offline
Posting Freak
Along with the other suggestions you need to check all your tune-up specs, timing, and cam timing. The boost is controlled by the BCS which is controlled by imputs received by the computer.

85 TC 5 speed, K&N filter charger, Ranger Roller cam, 3" exhaust system, manual boost valve, large VAM, SVO PE computer, front mount intercooler, underdrive pulley, ported upper and lower intakes,flow matched injectors, ported E6 manifold, 245/45/17 wheels & Tires
1985 TC

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