Power Fc Air Conditioning

[edizio]

Voltage to the ECU seems to be fine and I've connected the multimeter to the negative terminal and my earthing points on top of the rocker cover. Seems like the resistance is ok. I didn't expect there to be grounding issues as the wiring is very neat and tidy.

I may have found the problem though; turning the screw on the AAC isn't actually doing anything other than making idle leaner. I was expecting that turning it counter clockwise would cause the idle rpm to rise but it's not doing that at all. I would assume that this would affect both idle and the air con system.

[Ben C34]

How is the pipework to your iac run? Like factory or is drawing unmetered air?

[edizio]

It's factory pipework I believe

[Ben C34]

The only way it could go lean by adjusting the iac is if the iac is drawing unmetered air.

[edizio]

I'll take a picture of that and post it if that can help confirm? It's definitely going lean if I turn the screw anti-clockwise and not increasing the idle speed but there doesn't seem to be any additional piping down there.

There's no vacuum leaks in the system either though as I had a smoke test run which held pressure very well indeed.

[Ben C34]

Photo would help find out what's going on.

[edizio]

Will get that to you asap, it's late here so I'll do it first thing tomorrow!

[89CAL]

You need to disconnect either TPS or one of the plugs at the AAC to adjust it cant remember which one

[Dose Pipe Sutututu]

You need to disconnect either TPS or one of the plugs at the AAC to adjust it cant remember which one

disconnect IACV & the TPS

The AAC is purely for warm up (from what I see) and is not adjustable.

[89CAL]

Im just lazy and call the whole thing AAC lol. Not sure what it does with the mixtures when you dont unplug it, so just adding that in

[edizio]

Hey guys,

Sorry for the delay in replying, I've actually been off on business and had to drop the car back in the garage. I've ordered the AAC gasket so I'm going to take that off and give it a good clean when I'm back but it won't be for a good week or so. I have a feeling that my AC issues/dodgy idle when cold is probably down to something around here as the electrics seem fine.

I wonder if someone could clarify for me though: -

http://img.photobucket.com/albums/v150/tegguy/002.jpg

Is this the IACV? I thought that this was the cold air control valve - can this be taken apart and cleaned easily?

http://i217.photobucket.com/albums/cc252/kagekispirit/TechNical%20Support/Rb26AACvalve.jpg

This is the AAC and the part I just bought the gasket for and is the component that has the screw on it. I'm going to take this off and clean with carb cleaner until it shines!

[GTSBoy]

002.jpg is the AAC. Thermostatic, cold start valve.

The second one is in fact the idle control valve.

[edizio]

Oh right, why does the second one state that it is the AAC on the sticker?

I'm confused, sorry

[GTSBoy]

coz it's wrong.

[edizio]

Oh right, I see, ok well thanks for clearing that up. I'll report back when I get to work on the car.

[jiffo]

First photo is called the Air Regulator by Nissan.

It's simply a cold start/fast idle 12V bi-metallic strip valve which allows idle air to by-pass the throttle plate and flow directly to the plenum, thus increasing idle speed.

Engine bay heat will eventually close the valve irrespective of the 12V supply.

It's one bit of gear I always block on my Rb's as I find the AAC can do everything I need.

If you trace your idle air pipe work, you'll find a tee where the idle circuit splits with one circuit running to the AAC and the other circuit running under the plenum to the Air Reg. (brown plug)

Your car also has the idle bump up activated by the aircon.

A simple solenoid valve by-passing the AAC and allowing idle air directly to the plenum, thus increasing idle speed. (The solenoid with the purple plug)

[edizio]

Thanks for that! So I am going to be cleaning both of those and checking the pipe work for problems. I'll also do an idle re-learn on the power fc.

As far as unplugging the purple wire, I felt a little uneasy about that as I couldn't see why cutting out the air regulator would be a good idea. I can't see why nissan would put a part in whose problem can be solved by unplugging it lol. I guess I will have a go, I'm just not overly confident that I know what I'm doing so I don't want to be driving the car around with wires unplugged.

Regarding the screw on the second image, I.e. The one I thought was the AAC, which has the AAC sticker on it, is it the TPS wire that I need to disconnect? I've read so many posts that say that it's the brown plug, some people saying the TPS etc, is there a definite answer for this on the rb26? I expected that if i turn the screw the idle speed will change, but when I was doing this, I had disconnected nothing.

[jiffo]

My bad. For some reason I thought you had an R33/Rb25.

Rb26 doesn't have the purple plug solenoid for the aircon idle bump up.

It does have an AAC and an Air Reg, but you'd have to be pretty keen to find them, they're well buried under the plenum.

[edizio]

I see, well I can get at them, I've got the tools to take them off and I'm hoping that cleaning it out may help the air con problem and the idle issues.

Do you know if it is the brown plug or the TPS that needs disconnecting to adjust the idle rpm screw?

[89CAL]

The manual I have says to remove the AAC plug while adjusting idle. Its a pretty poor picture