Small butterfly position

[frostbite]

Hey guys

How can you tell what position the small butterfly is in?

I was playing with the vac hoses and put a constant vacuum on the lower actuator witch pulled the rod down, it starts lumpy but a blip of the throttle and smooths out, shut down is not rough but a little shake.

with the hoses back to normal, if you push the rod up into the actuator the engine starts to choke shake and go a bit quieter, my egr is disabled with the ballbearing in the top hose.


cheers

[NiftyNev]

The vacuum mechanism for this is two stage. Lower hose is butterfly partially closed at idle if hoses have not been blocked. Opens again when throttle is off idle. It's ok for the EGR Valve to be blocked off. Upper hose (and lower) have vacuum at engine shutdown to close the butterfly completely for a few seconds.

If you want to disable butterfly except for engine shutdown disconnect and plug bottom hose and add a T to top hose and connect to where bottom hose was. Vacuum is needed at both to close butterfly when ignition is turned off.


Nev

[frostbite]

The vacuum mechanism for this is two stage. Lower hose is butterfly partially closed at idle if hoses have not been blocked. Opens again when throttle is off idle. It's ok for the EGR Valve to be blocked off. Upper hose (and lower) have vacuum at engine shutdown to close the butterfly completely for a few seconds.

If you want to disable butterfly except for engine shutdown disconnect and plug bottom hose and add a T to top hose and connect to where bottom hose was. Vacuum is needed at both to close butterfly when ignition is turned off.


Nev

so that will keep the valve shut when the main throttle is open?

cheers

[NiftyNev]

so that will keep the valve shut when the main throttle is open?

cheers

No. The small butterfly is open at all times other than when the engine is at operating temperature and idleing or at engine shutdown. If it closes any other time something is not right.

A little test to do if you want to know it is working as it should. Start engine from cold., butterfly should be open (rod is down). As engine warms up watch the rod. It should pull up and partially close the butterfly at a certain engine temperature. Slightly open throttle. Butterfly should then fully open. If all that is ok then shut engine down. Butterfly should close completely as the rod is pulled all the way up.

Nev

[NiftyNev]

Here's a pic. As the rod moves this part will be pulled down. It will move about half way down at idle and all the way down at engine shutdown.



Nev

[frostbite]

So when the rod is fully up the valve is closed, this makes the bov work properly. If the vac hoses are put back to normal the bov is useless