Secondary activation question

[qwik huh]

I understand the computer sends a signal to open the secondaries at 3950. Is the signal coming from the PCM directly or is it from the CCRM? And are there differences in how it is activated from year to year? I have a mix of parts in my car right now and I am trying to sort it all out. The body is a 94 LX wagon, the engine is a 95 3.0 out of a wrecked SHO, and the computer and CCRM are out of my recently wrecked 92 SHO. The 95 engine was in the 92 SHO before and always felt like it pulled hard but I never got that sudden tone change at 4000 rpms like I used to. I am guessing they are stuck open. They open when the car is off and then vacuum cloes them correct?

 

[SHOtimer]

Correct, they are closed when the car is off, and then vaccuum closes them. You can see if they are opening and closing by manually revving the motor on the TB and watching the actuators. It is possible you have a vaccuum leak in the secodary vaccuum lines, and they run over the intake and after many years can harden and leak. You may also have a leaky vaccuum canister (the round black drum on the rear of the intake). Their are also vaccuum lines on the back of the intake for the secondaries - I'd look at those too.

Doug

 

[SHOZ123]

The '92 manual does not show the secondary solenoid control. The '93 on up do and the signal comes from the PCM.

 

[SASHO91]

Doug, you mean open with the car off.... right?

 

[projectSHO89]

The '92 manual does not show the secondary solenoid control. The '93 on up do and the signal comes from the PCM.

Sure it does, it's just called the "Inlet Air Solenoid" (IAS). Later models refer to it as the Intake Manifold Runner Control (IMRC).

All years and versions of the SHO are controlled the same.

Steve

 

[SHOtimer]

Doug, you mean open with the car off.... right?

Yes.

Doug