Re: Lack of Boost, '88 5ktq

["Scott Mo." <scottmo@teleport.com>]

Mike,

>The patient is a 1988 5ktq. I've been fighting a lack of boost problem >for some time and would like to seek the list's advice before      proceeding.

The Multi-funtion Temp switch should be tested as this could limit the
boost if it thinks the engine is too hot. Go to

http://www.teleport.com/~scottmo/boost.html

The Waste Gate solenoid can be tested using the ECU Output Tests. Go to

http://www.teleport.com/~scottmo/ecuf.html

You can also test out the WG solenoid by connecting an LED across the
solenoid connections and then take it out for a test drive. Go to 

http://www.teleport.com/~scottmo/ecusys.html

>      I'm thinking the lack of boost is on the exhaust side and I'm >guessing either the hot side of the turbo or a blockage in the exhaust >system     (cat?). What would be the best way to proceed to try and >isolate the problem?

If you have the pre-cat sniffer pipe which is bolted to the intake
manifold (blue cap), you can connect a pressure gauge and check the
exhaust back pressure. Go to 

http://www.teleport.com/~scottmo/boost.html

and check out the Exhaust section. I have added some new info on
checking the back pressure.
HTH
-- 
Scott Mo.
1989 200TQ
http://www.teleport.com/~scottmo