Jim Grant's Tech Tips
'87 Mazda RX-7 Turbo, No Turbo Boost
The turbo is not working
on my87 Mazda RX-7. One mechanic told me, it might be the igniters.
Is that right? Is there a way I can test them myself with a light tester?
- Paul H.
The turbo on your Mazda
is powered by exhaust gases. Where the ignitor falls into that diagnosis
is questionable. Exhaust gases spin a turbine which, in turn, spins another
turbine that increases the air flow/pressure to the intake of the engine.
The pressure is monitored by the computer via a sensor in the intake manifold.
In the event pressure to the engine becomes too high a computer controlled
solenoid activates a device called a waste gate to divert exhaust gases,
resulting in a drop in the air flow/pressure to the engines intake.
If there is no boost (increase of air flow/pressure) from a turbo, then
check to see if the turbine spins freely and smoothly. If it does not
the assembly needs to be replaced. If all checks okay then inspect the
operation of the waste gate. It is not, uncommon for the linkage or the
waste gate valve to stick in the dump/divert position. Usually a little
cleaning, lube and working of the valve and linkage will correct that