Mrmerlin

Ian please test the system as I have described .

Please report if you see the tape that you stuck onto the flappy shaft move. when you start the engine.
the shaft will quickly open and close during the initial start sequence.
THUS making it very difficult to see if you getting any power to the valve, as it will be a brief 2 second power pulse.

Otherwise its difficult to test as the flappy will only self test on the start sequence,
and then it will only activate if enough load and RPM are placed on the engine,
and then for only the most brief amount of time.
Thus the easiest way to test the flappy system is how I described on the initial engine start.

Also please reread post 9 as it describes the function of the vacuum lines and how the valve works,
based on your questions you did not pick up the subtle bits of wisdom on how the valve functions and how you should test it.

sprie

Hi MrMerlin
I have done the test. I removed the cap, put a line of tape on the flappy valve, and started the engine. But no sign of the tape moving. For completeness, i repeated the test with the cap back on - ditto. I then pulled the hose off that leads to the flappy valve and put MityVac on it, pulled a vacuum and i could see the tape move 90%.
Does that imply i have another issue somewhere?
Thanks

Geza

In order for the valve to open during the engine start "self test", there needs to be enough stored vacuum available (no leaks in the vacuum reservoir). Pull and hold a vacuum on the grey line near the brake booster, then start the engine and see if the shaft rotates during start-up.

FredR

Ian,

As Mr Geza says the vacuum reservoir has to be charged - if you have not done so already put the vacuum gauge on the connection occupied by the line to the HVAC system- it shoud pull about 19 inches Hg vacuum on a fully warmed up engine [less if the engine is not warm and is still idling at a faster speed]. The actuator needs about 7 inches of Hg to physically overcome the flappy resistance so anything about 10 inch Hg and deeper should be fine. If you have a scope you can also check to see if the solenoid is getting the electrical signal. You can probably also see the signal pulse using your multimeter or so I would think.

Mrmerlin

Thanks for the reminder about having a valid IE charged vacuum source.

NOTE the open signal comes for the computer,
if you want to test the connection for power,
fit a 194 bulb into the valve connector and start the engine the self test signal doesnt last long so watch the bulb carefully..