Hot Rod Air controlled by the computer?
Hot Rod Air controlled by the computer? Alrighty got an AC quesiton. Im running a hot rod air setup. Speartech brought out the ac compressor wire(single green wire) on the vcm end of the harness and the stock compressor pigtail on the other end. I want the vcm to tell the compressor when to cut on and off. That way when I turn the ac on the idle adjust and also when I reach higher rpm the compressor kicks off. Anyone have a wiring schematic or advice on how to wire this thing up to my hot rod air setup?! thanks.
Not quite sure what you are calling the VCM. The A/C is controled through the PCM by the A/C request wire. The wires for the low and high pressure sensors also run to the PCM. Have to see if I can find the diagram
Re'
Re'
By vcm I mean pcm. Ecu, pcm, ecm, whatever the crap it is. I never get it right. I call it something different every time. ha. Iv seen some post about brazing in a pressure sensor. I think the hot rod air may already have a pressure sensor. I will have to check today. Thanks for the schematic
Launching!
Joined: Jul 2004
Posts: 223
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From: Potomac, MD
I ran my Classic Air system through the pcm and works much better in terms of smoothness. You have to put in the gm pressure sensor on the high side. Adaptor fittings for this are available. Then just wire as per diagram. Set parameters with tuning software.
Prior to runing it this way the AC would engage noticeably. Through PCM engagement is seamless.
Prior to runing it this way the AC would engage noticeably. Through PCM engagement is seamless.
Staging Lane
Joined: Mar 2007
Posts: 65
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The ECM I have is from a 2006 GTO. From 2006 forward the A/C request and A/C status signals are in the body control module (BCM). These signals get sent to the ECM over the CAN bus. I didn't get the BCM with the pull-out. Does anyone know of a workaround for this? Is there an aftermarket part that will input these signals?
Instead of brazing in the pressure sensor I was thinking of running relays maybe? The pcm would still cut the ac off when the rpm increased and adjust idle when the compressor cut on. I have hp tuners so I can control when it kicks on and off. Its a sanden compressor. I dont believe it is a variable compressor but I may be wrong. If its not variable then it doesnt need to read the changing pressure sensor, it only needs to know-cut off here and here? correct?
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I think you're better off just brazing in the sensor, as it'll allow the PCM to control high and low pressure cutoff, as well as the fan based on AC pressure. Having a pressure based cutoff is a necessity to keep the system safe, so why not take advantage of what the PCM can do? Also, the variable displacement really doesn't effect much with the electrics. On my car I just tied the ac thermostat into the ac request wire, so the compressor can be shut off if it gets to hot or cold in the car, which is how most places that have you use a Sanden want you to do it.
For the guy with the GTO PCM, I am using a C6 computer with no BCM, and I have this running using the green wire the OP talked about and the stock compressor and pressure sensor pigtails. I also have the schematic for the Gto if you've got any questions about it.
For the guy with the GTO PCM, I am using a C6 computer with no BCM, and I have this running using the green wire the OP talked about and the stock compressor and pressure sensor pigtails. I also have the schematic for the Gto if you've got any questions about it.
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Joined: Jul 2004
Posts: 223
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From: Potomac, MD
The BCM would allow automatic temperature control, dual zone, etc. Since won't have ths BCM would not be necessary.
The pcm alone should be able to control AC compressor with inputs from pressure sensor, engine speed, and engine temp. If these conditions are within specs then AC compressor clutch signal is turned on which goes to AC relay. This relay circuit I believe is different from others in that signal is 12v+, rather than ground.
I aluminum brazed in fitting for the 3 wire pressure sensor.
The pcm alone should be able to control AC compressor with inputs from pressure sensor, engine speed, and engine temp. If these conditions are within specs then AC compressor clutch signal is turned on which goes to AC relay. This relay circuit I believe is different from others in that signal is 12v+, rather than ground.
I aluminum brazed in fitting for the 3 wire pressure sensor.
Last edited by dsrour; Apr 5, 2009 at 08:03 PM.
You can get the fitting from Docsblock. Watch the videos on how to braze.
http://www.docsblocks.com/proddetail.asp?prod=AC0146
Another option is from Tubesnhoses. Part # BL1301-4. With this fitting, you dont have to braze it on. It needs to be crimped on though
http://www.docsblocks.com/proddetail.asp?prod=AC0146
Another option is from Tubesnhoses. Part # BL1301-4. With this fitting, you dont have to braze it on. It needs to be crimped on though
Staging Lane
Joined: Mar 2007
Posts: 65
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Chris, If you can PM me the schematic that would be great. I'd like to see how you paralleled the A/C turn on signal with the ECM turn off signal. Thanks, Mike
mjcorullon@netscape.net
mjcorullon@netscape.net
Staging Lane
Joined: Mar 2007
Posts: 65
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You can also try this bolt on clamp adapter from Ready-Aire. Made for 1/2" hard lines.
http://shop.oreillyauto.com/ProductD...artNumber=2985
http://shop.oreillyauto.com/ProductD...artNumber=2985
Launching!
Joined: Jul 2004
Posts: 223
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From: Potomac, MD
Docs Blocks part # is AC0146 its M10 1.25 thread. Get several as it takes a bit of practice to get down the brazing. Its easy to overheat metal and melt the fitting I found. You can also get a crimp hose fitting with this port.
Below is diagram for 07 C6.
Correction to my previous post the pcm turn on signal is grounding the relay coil rather than 12v+ as stated previously
Below is diagram for 07 C6.
Correction to my previous post the pcm turn on signal is grounding the relay coil rather than 12v+ as stated previously
Last edited by dsrour; Apr 5, 2009 at 08:47 PM.
I was thinking of going out to the junk yard and getting all these parts. Even the fitting to braze in. There is a yard with the type of vehicle my engine came in. I may do that. What all would I need to swipe while I was in there getting parts?
TECH Resident
Joined: Oct 2004
Posts: 800
Likes: 1
From: Simi VAlley,CA
That fitting is part of the factory hard-line and would be difficult to splice into your system. Get one of the above mentioned fittings, you will be better off. My PCM runs my Hot Rod Air system very well. It provides the "idle-up" just like the factory system is supposed to. I used a splice-in barbed fitting for the sensor in the "high side".
Launching!
Joined: Jul 2004
Posts: 223
Likes: 0
From: Potomac, MD
Pressure sensor:GM part #22664328. A bit pricey ~$50 if I recall.
Another option for port as noted above from Oscar www.tubesnhoses.com.
Tubes n Hoses part number BL1301-4.
A crimp fitting
Another option for port as noted above from Oscar www.tubesnhoses.com.
Tubes n Hoses part number BL1301-4.
A crimp fitting