Double Throttle Control Actuator
08-23-09, 03:42 PM
#1
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Double Throttle Control Actuator
I have been having a couple problems with my jdm 1993 mazda rx7 type r.
There is a very bad hesitation at 3000 rpm ONLY at hard throttle. After 3000 rpm I can apply hard throttle and it will pull normally.
Also I have installed a boost gauge to assist with the problem and I am only pushing 5 psi of boost at WOT throughout the whole rpm range.
I was researching some things that coulb possibly be the problem and I read that if the double throttle control actuator is malfunctioning you will not boost past 5 psi.
Also when the vehicle is at operating temperature and you remove the hose leading to the actuator you should have 0 vac. I get no change in vac when i remove the hose.
Im not sure on this but i heard that when idling and reving past 5000rpm that actuator rod should move. But mine doesnt.
From what i have researched i am thinking that this could be my problem. But i am looking for some feedback. Also is the best plan of action. Remove it? or replace it?
Thanks for taking the time to read!
There is a very bad hesitation at 3000 rpm ONLY at hard throttle. After 3000 rpm I can apply hard throttle and it will pull normally.
Also I have installed a boost gauge to assist with the problem and I am only pushing 5 psi of boost at WOT throughout the whole rpm range.
I was researching some things that coulb possibly be the problem and I read that if the double throttle control actuator is malfunctioning you will not boost past 5 psi.
Also when the vehicle is at operating temperature and you remove the hose leading to the actuator you should have 0 vac. I get no change in vac when i remove the hose.
Im not sure on this but i heard that when idling and reving past 5000rpm that actuator rod should move. But mine doesnt.
From what i have researched i am thinking that this could be my problem. But i am looking for some feedback. Also is the best plan of action. Remove it? or replace it?
Thanks for taking the time to read!
08-23-09, 09:45 PM
#2
With the engine off, the double throttle butterfly will be open (allowing air to flow through the secondary intake runners). The vacuum actuator is controlled by a solenoid... when the ECU grounds the solenoid it will send vacuum to the actuator and the double-throttle butterfly will close (preventing air from flowing through the secondary intake runners).
According to the Mazda factory service manual, the stock ECU controls the solenoid based on coolant temperature. When the coolant is cold the double-throttle butterfly will be closed, and when the coolant is warm the double-throttle butterfly will be opened.
I doubt you would cause a vacuum leak by removing the hose unless the engine is cold and the ECU is holding the actuator closed. You can move the lever by hand to see the open vs. closed position, or have someone else start the car while you watch the lever (should be able to see it on the back side of the UIM).
There are a couple of good boost troubleshooting link in the 3rd Gen FAQ and Useful Links thread, it's one of the sticky threads at the top of this section.
According to the Mazda factory service manual, the stock ECU controls the solenoid based on coolant temperature. When the coolant is cold the double-throttle butterfly will be closed, and when the coolant is warm the double-throttle butterfly will be opened.
I doubt you would cause a vacuum leak by removing the hose unless the engine is cold and the ECU is holding the actuator closed. You can move the lever by hand to see the open vs. closed position, or have someone else start the car while you watch the lever (should be able to see it on the back side of the UIM).
There are a couple of good boost troubleshooting link in the 3rd Gen FAQ and Useful Links thread, it's one of the sticky threads at the top of this section.
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