IMRC cotrol.

[msojka]

I replaced one IMRC actuator about 20,000 miles ago. At that time the actuators worked as they should, opening at 3,000 rpms and above. Now they open up just as the accelerator is moved. The vacuum appears to be sufficient and have not found any leaks. Has anyone had a control problem like this?

[DRW1000]

Originally Posted by msojka

I replaced one IMRC actuator about 20,000 miles ago. At that time the actuators worked as they should, opening at 3,000 rpms and above. Now they open up just as the accelerator is moved. The vacuum appears to be sufficient and have not found any leaks. Has anyone had a control problem like this?

I believe the year is important as some years are vacuum controlled and others are electrically controlled...............So what is the year and which engine?

[BCMedic]

You might want to first mark all positions with whiteout and then remove the actuator cables and sensor linkage and check the return springs. As DRW mentioned, they are either electro-mechanical or a vacuum system. One of them has an internal spring and the other has a return spring mounted on the IMRC plate. Also check for sticking or binding on rotation.
Careful! The springs are quite strong!

[msojka]

Originally Posted by DRW1000

I believe the year is important as some years are vacuum controlled and others are electrically controlled...............So what is the year and which engine?

The year is 1998 with the 3.8 liter engine. My valves are vacuum operated and a electric solenoid valve controls the vacuum to them at the proper time. The valves themselves are monitored electrically. I was wanting to know how to troubleshoot the solenoid control that sits at the hard to get to rear side of the engine on passenger side. Thanks.

[BCMedic]

Originally Posted by msojka

The year is 1998 with the 3.8 liter engine. My valves are vacuum operated and a electric solenoid valve controls the vacuum to them at the proper time. The valves themselves are monitored electrically. I was wanting to know how to troubleshoot the solenoid control that sits at the hard to get to rear side of the engine on passenger side. Thanks.

Info:
On the direct mounted vacuum actuator system, the return springs are located within the vacuum actuator. The PCM commands a vacuum control solenoid allowing the vacuum to pass to the vacuum actuator drawing the valve plates closed or releasing the vacuum allowing the actuator to push the valve plates open. Substantial opening and closing torque is applied in both systems. Care should be taken to keep fingers away from the lever mechanisms when actuated. It also provides a switch signal to the PCM for the plate position.


Above 2950 rpm :

• The solenoid is de-energized.
• The vacuum actuator holding the valve plate closed is vented.
• The spring-loaded vacuum actuator pushes the valve plate open.

Have you tested the solenoid connector for voltage before and after the 2950 RPM mark?
If you have voltage up to 2950 RPM and then it drops off to de-energize then you need to test the vacuum actuator. If not then you may have a switch signal fault or a wiring, connector or PCM issue.