95 MTX secondary

[josho]

I just purchased my 4th gen 2 this the first car i have owned that you can't hear the secondaries come in, Is this a good thing or a bad thing?

 

[jimtash]

Are the even closed? Start the engine and watch the actuators. They should be in the closed position and you can verify this by the looking at tang on them which should be in the upright position.

 

[kevinspann]

Depends. Are they working? If so, does it still have the airbox inside of the fender? Remove it, and it'll make the intake louder when on the throttle.

 

[rubydist]

if they are open with engine off, and closed with engine running at idle, they still may not operate properly if the little vacuum tank on the rear of the intake has a leak. so you also need to check to see that they don't open every time the throttle gets mashed to the floor.

 

[josho]

ok so i checked the tang and it is in the down position which is open right? and it doesnt change, engine off, idling, or WOT.. so i assume now that its not working... how do i check for leaks or trace down the problem?

 

[jimtash]

There's a canister at the rear of the manifold with 2 hoses coming out of it. One of the hoses plugs directly to the manifold and one to an electrical terminal. Make sure the electrical connector is plugged in and that the vacuum hoses are still attached.

 

[josho]

everything is plug in and seems to be fine but no response at all from the butterflies.... there is a vacuum line missing in the front where the big one from the throttle body comes down could that be a problem?

 

[jimtash]

No but I suggest you plug it in. It's for the PCV.

If everything is plugged in for the secondaries then the switch itself which controls them is probably bad. See if you can find one on here.

 

[rubydist]

you need to determine if the issue is no vacuum or the electric control is bad.

you will need to verify that you have vacuum going to the canister on the intake is. if no vacuum, run that down and get vacuum to it.

if you have vacuum going to the canister, you will need to confirm that the canister does not have a leak.

if that is good, you will need to verify that neither of the actuators on the butterflies are bad - they can leak all the vacuum away if the diaphragm is bad.

if all that is good, you need to trace electrical stuff to find out what is going on there.

 

[josho]

checked vacuum; good. checked for canister leak; none. checked actuators; good... I swapped the switch out of a known working SHO and it still doesn't work... so... electrical issues somewhere..

 

[AREA 91]

This is a long shot, but I will sugguest it.
It is possible to swap the climate control and secondary plugs back there.
If this happened, it will blow out the secondary circuit in the computer.
The only wat to fix it is a new pcm.

The wires going to the secondary canister are red and green (like christmas).
I pulled my hair out years ago diagnosing this.

 

[zach44102]

If they still dont work with a good canister and good vacuum then i would start looking at the wiring/ECU

I have had secondaries quit working before because of a ECU

 

[josho]

ok so are the two wires going to that switch just a hot and a ground? i took the switch off and put power straight to it from a battery and you can hear it switch so i assume so... anybody know?

 

[josho]

This is a long shot, but I will sugguest it.
It is possible to swap the climate control and secondary plugs back there.
If this happened, it will blow out the secondary circuit in the computer.
The only wat to fix it is a new pcm.

The wires going to the secondary canister are red and green (like christmas).
I pulled my hair out years ago diagnosing this.

i got red and green wires... are the climate control different colors?

 

[AREA 91]

i got red and green wires... are the climate control different colors?

Yes. I can't remember off hand what those colors are.
The automatic climate control plug is located in the "hard line" going to the heater core.

 

[jimtash]

Do you have power at the red wire itself?

 

[josho]

I have power but no ground. wired a ground to the plug and started the car and they closed but would not open... so i guess pcm

 

[zach44102]

Find a x2j ecu. Swap it in. Im not sure but i might have one laying around somewhere

 

[Off Road SHO]

I have power but no ground. wired a ground to the plug and started the car and they closed but would not open... so i guess pcm

The secondaries are spring loaded in the open position. The only way to close them is by applying vacuum to the vacuum motors on each bank. If the motor is not running and therefor not producing vacuum, the secondaries should be open.

When the motor is started and generates vacuum, that vacuum closes the secondaries. When the RPM's reach about 3950, the PCM sends a ground on the non-red wire to the Intake Runner Control solenoid (on the back plenum) which then opens a valve and gets rid of the vacuum (by letting in air). And what happens when the vacuum motors don't have vacuum anymore? They go back to their spring loaded default position, which is open.

So in your statement above, the secondaries did not do what they were supposed to do, that is open when there is a ground on the non-red wire.

Your next logical step is to see if the PCM is outputting a ground on that non-red wire, at the PCM's wire harness plug, when the rpm's reach 3950.

You can do this with a 12 volt test light. Hook one side to + battery and the other side to the non-red wire at the PCM. When you rev it up in neutral, the test light will light at anything above 3950 and go out when below 3950.

If you get light above 3950 at the PCM, but not at the IRCM plug, you have an open in the non-red wire somewhere between the two.

I hope this helps.

Tom

 

[zach44102]

This car green and buy it in alabama? Lol