A/C idle up and Amplifier (1 Viewer)

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How’s it going guys. So I’ve read up on a/c amp thread and still can’t seem to get my a/c right. Could these couple missing parts/fuses on my amp be causing it?


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Your AC amp looks normal, some of those parts weren’t populated from the factory.
How’s it going guys. So I’ve read up on a/c amp thread and still can’t seem to get my a/c right. Could these couple missing parts/fuses on my amp be causing it?
Good to know and thanks for the reply! Just really trying to figure out why it continues to cycle on and off even after following the instructions on the amp thread.
 
Have you checked your low and high side pressures?
Is the system fully charged?

Try to describe what’s going on, so we can help you.
 
I had an a/c shop covert to r134 a few months ago and recently installed the the a/c idle up vsv components. I also checked voltage and I am getting 12v. My current issue is getting my idle up to stay at the 1000 rpm. It’ll only idle up for about 20-30 seconds, then go back down to regular 650 idle. It does that repeatedly. I tried adjusting the blue rpm knob and the red temp knob with no success.
 
Have you checked your low and high side pressures?
Is the system fully charged?

Try to describe what’s going on, so we can help you.
And no I have not checked the high and low psi pressures. Might do that tomorrow
 
You might have a small refrigerant leak, and when the compressor kicks in low pressure switch gets triggered
and shots down the compressor and your idle up solenoid.
 
The compressor is supposed to cycle on and off. The frequency of cycling is probably related to ambient temperature, fan speed and other parameters that effect the load on the evaporator. If you think it is cycling too much then maybe check the temperature sensor.

I don’t think it is a leak because once it leaks out enough to trip the low pressure switch, I think the compressor would stay off.
 
It’ll only idle up for about 20-30 seconds, then go back down to regular 650 idle. It does that repeatedly.
The compressor is supposed to cycle on and off. The frequency of cycling is probably related to ambient temperature, fan speed and other parameters that effect the load on the evaporator.

This is what mine does with properly charged R134a. It doesn't stay at 1000 RPM all the time with those components whenever you turn on the A/C. It cycles on and off and idles up the engine when the compressor engages. Sounds like its working properly OP. Are you wanting it to stay at 1000 RPM idle?
 
The compressor is supposed to cycle on and off. The frequency of cycling is probably related to ambient temperature, fan speed and other parameters that effect the load on the evaporator. If you think it is cycling too much then maybe check the temperature sensor.

I don’t think it is a leak because once it leaks out enough to trip the low pressure switch, I think the compressor would stay off.
These are valid points and true except the last one.

There is a scenario where your system is partially charged and the pressure is above the trigger point for the LPS to be activated.

With the compressor off the pressures on the low and high side are equal.
The compressor can be turned on.

When the compressor is turned on the pressure on the high side goes up and the low side drops. If you have a partially charged system, your low side pressure could drop below the LPS trigger point and cut the compressor.

After some time the pressure on the two side are starting to equalize, the low side pressure rises above the LPS trigger point and the cycle will start again.

In a normally working system the compressor will cycle on and off if you’re not taking enough heat out.

Your problem could be electrical,
I’m just saying that the number one cause of automotive AC system failure is leaking refrigerant.

Just my $.02
 
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What is the proper way to setup the AC Amplifier's "compressor on" dial?? I understand that dial determines what the minimum RPM for the compressor to turn on. But, how do you set that up in conjunction with the AC Idle up speed? And.. what's the correct AC Idle up RPM? I couldn't find that in the FSMs anywhere.

I've got my AC Idle up set at 800 RPM right now, which seems correct.

But, if the compressor will only turn on when the switch is pressed, and pressing the switch automatically raises my RPM to 800, what's the point of having the dial??
 
This is what mine does with properly charged R134a. It doesn't stay at 1000 RPM all the time with those components whenever you turn on the A/C. It cycles on and off and idles up the engine when the compressor engages. Sounds like its working properly OP. Are you wanting it to stay at 1000 RPM idle?
I always assumed it should stay at the idle up RPM, Until the a/c or blue button is turned off. I was told by a couple of people and also thought I read it somewhere. Thanks for the clarification! I just want it working like it should.
 
What is the proper way to setup the AC Amplifier's "compressor on" dial?? I understand that dial determines what the minimum RPM for the compressor to turn on. But, how do you set that up in conjunction with the AC Idle up speed? And.. what's the correct AC Idle up RPM? I couldn't find that in the FSMs anywhere.

I've got my AC Idle up set at 800 RPM right now, which seems correct.

But, if the compressor will only turn on when the switch is pressed, and pressing the switch automatically raises my RPM to 800, what's the point of having the dial??

The blue knob on the AC amplifier is supposed to be set to disengage the compressor if the idle drops to the range 600-700 rpm (factory idle setting is 650 rpm). The setting is low enough that if the amplifier remains on the engine could stall due to the extra load.

The AC idle up should be set to increase the idle speed to 900-1000 rpm when the compressor is engaged. This provides a little extra engine power when the AC compressor is runnning.

It does seem a little bit "belt and suspenders" but this is how it is. These instructions are on pages AC-35 and AC-15 respectively in the Chassis & Body manual.
 
I always assumed it should stay at the idle up RPM, Until the a/c or blue button is turned off. I was told by a couple of people and also thought I read it somewhere. Thanks for the clarification! I just want it working like it should.
I think the AC compressor cycles on and off on every automobile. You just don't notice it so much on newer FI vehicles as they can squirt more fuel into the mixture instead of raising the idle speed. I do notice the cycling on my cira 2000-2003 BMWs (E46 & E53).

Also if you set your AC idle up speed to high, the vacuum circuit becomes unstable and will rapidly oscillate between high and low RPM.
 

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