Sorry, I just posted at the same time. I am not sure if it came through. Here it is again.
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maybe I have a problem with Im 324
No. There are two parts to the circuit. The LM324 controls the MAF signals and the relay controls the AFC valve.
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I test the relay and it work, check points and they open and close
Did you just put voltage to the pins and listen for a click or did you test per my instructions for output voltage levels?
If you did the test as in the instructions and it passed, then the relay 'loaded' by the AFC needs to be tested next.
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I notice that when you open and close the ignition switch (with the plug on), the flapper make a sound but it does not close
The relay will click every time the ignition is turned off and on when in Park or Neutral.
The valve will move when in Park or Neutral and when the trucks CPU puts voltage to pin 7.
Put the SEGR back in and measure pin 7 voltage at engine shut down. Push a needle through the wire if you like for the positive lead and clip the negative to the frame. The voltage at pin 8 should be the same for shutdown.
If the contacts in the relay are burnt, you may see no problem on the bench. When you put a load on it (like the valve), the resistance of the burnt contact steals some of the voltage. The valve may move slightly but not enough to do the job.