NEED HELP ON Rb25det NEO/S14 Air Condition Wiring

[BlackRB]

Hey everyone, I really need some help on rewiring my AC unit. I have try to hook up AC on my S14 w/ Rb25det NEO swap for a while now, but didnt know how too wire it correctly. I have repeatedly readed some of the post in NICO about RB5det A/C, but not really sure if that will apply to the RB25det NEO or not. Here is what i have done so far, I have all ac line connect into the Ac unit already such as, Low and High pessure side, ect..., but few issue that i have had is the Low pressure line (front compressor to the fire wall) dont have the misture trap can on it (just one straight line with the FreeON Valve)(the picture below will describe it). The High pressure line connect but no FreeOn VALVE there to pump in the refrigerant just a smooth line (I ONLY pump freeon from the low pressure line). Far as the electrical part goes, I have remove the AC relay in the fuse box (right next to the battery) on the engine bay, then use the toggle switch and connect to two out of the three wire in the AC relay to the toggle switch (dont really know that wire does, but is work) and turn the switch on when ever i need AC ON. I did vaccum the line and pump freeon in it and yes they are working currently. It work fine, but i have found few problems with it recently. First, i cannot kept the toggle switch on while crank up the car cause it will burn the 7.5A fuse and the same fuse box. Second, it overpressure the system when in car sit still while motor is running about 10mins and pressure valve from the compressor release the SOME refrigerant out of the system. Fourth, it when the ac kick in I can feel that the car decrease it power alot i dont know if that is normal. Last, When driving the car with AC on for about 30mins or less. The motor get really HOT almost to the stage of overheating, but if i turn AC off then is go back to normal temperature. I really dont know a better way to rewire the AC to make it work better. I Dont KNOW if the wire diagram on the NEO is different from the OTHER RB25 motor. Some one please help Rewire the AC. I'm not a good writer, so please excuse me for any grammar error. Thank you all.

This is new upgrade picture. I hope this will help.Modified by BlackRB at 4:23 PM 6/19/2009
Modified by BlackRB at 4:34 PM 6/19/2009

[BlackRB]

NEW PROBLEM FOUND, I have drive with AC on for about 30mins or less doing 80mph and the car run HOT HOT almost to the point of over heating the car. But when i turn OFF the AC everything go back to normal. Some one please help.

[Carl H]

welcome to the world of cooling issues and an rb engine swap.you most likely need to upgrade your fans as well as your radiator as the radiator will be recieving even LESS airflow thru it since you have the ac condensor in place.

[Bluefire]

Man that was super hard to read. forums really need an auto correct. Anways from what I can tell, you basically wired a switch directly to the compressor. This is not a good idea! basically your pressure switch is no longer hooked up, as well as ficd. You also don't have a high side port to check pressure out of the compressor. Follow the RB AC thread and wire it correctly. This will take care of most of your problems..

[BlackRB]

Thank you CARL, but will the help the overheating issue too?Thank

[BlackRB]

Sorry about the grammar, i did follow that threat and read several time but still didnt help me that much.

[Carl H]

neo engine does not have an fcid...uses an iacv idle up like the 20/26.

[BlackRB]

Sorry CARL i confuse when reading too much from other NICO ac RB threat. So let start from the beginning, how do it wire up the AC without having to use the custom toggle switch (i want to use the AC switch from the climate control). Start form which wire and where. Thank agian CARL

[BlackRB]

Can i use the wire diagram from <Ramius83> in this threat? Will is work the same. zerothread?id=125307

[Darius]

You have to have the drier in line between the condenser and the evaporator not only to dry the refrigerant, but that also has the triple pressure switch on it to cycle the compressor on and off. If you just run the compressor all the time, it will overpressure and either bust a line at 300 psi or burn up the compressor.

Second, your wiring is not going to work the way you have it wired in. You need to wire the relay for the AC compressor to the triple pressure switch.

Third, it is unbelievably easy to wire the AC up to the ECU so it steps up the idle when the AC is on. All you have to do is connect 3 wires at the ECU and it is done. I'm sure the NEO has the same setup even though the pins might not be the same.

[BlackRB]

Sorry for the confusion Darius and everyone. This what i'm try to say. Also Darius can you tell what is the THREE WIRE and how can i get it to work pressing the AC swtich and AC unit control. Thank you so much.

[Darius]

Typically, there is a vacuum port on the low pressure side and a charge port on the high pressure side. Someone correct me if I'm wrong, but it is good practice to evac the system and vacuum test it prior to adding refrigerant to check the condition of the system as a whole. I've never done this before, but will do it soon.

I'm not sure what the large part on the fitting is for. I don't think you need it since I've seen many other cars run without something like that. Odd.

As far as the wiring goes, I believe it is the Y/B wire from the climate control unit, the pink wire at the ECU plug (pin 49?), and the B/P wire from the AC relay that goes onto the triple pressure switch. All 3 need to be wired together.

Search through 300Plus' thread (zerothread?id=267002)and it describes it in there.

The switch on the dash grounds the Y/B wire, which grounds in the ECU to tell the idle to step up since the compressor is drawing a load. The grounding on the B/P wire closes the relay that powers the compressor and also completes the circuit to half of the triple pressure switch. I really need to get on drawing up a wiring diagram for this because it is stupidly easy. Shouldn't take more than an hour after you find all the wires.

[BlackRB]

Thank alot for your advice <Darius>. The guys that vacuum my AC, put the vacuum to the Low-pressure line service valve, then vaccum and pump (while idle about 3k rpm) refrigerant in that same valve. AC does get very cold, but im not so sure if this way it safe or not. Also the large can right after the fitting, people told me that this can it might be there for trapping moisture, but we really dont need it. BUT they not so sure if it work any different when there is NO service valve over the High pressure line. I ll try to follow up on that too. Thank

[BlackRB]

BTW Darius, that is very clear desription. I understood that 300plus saying that we have to connect the AC dash buttons wire & the AC relay wire from S14 F4 plug and RB25 AC switch together. But What about the AC relay control signal and Refrigerant pressure signal form the RB25DET NEO ECU. Do you leave this two wires disconnected. Please tell me if im wrong. Im very new to this stuff. Because the RB25det and the NEO are little different so I was thinking about doing this:

S14 A/C dash buttons ---------->rb25 A/C Switch and refigerant pressure signal (ECU)

Then

s14 A/C Relay (to ECM) --------->rb25 A/C relay (ECU)

I got this from study this two wire of s14 F4 plub that run to s14 ECU and the NEO ecu. I really dont know if that is going to work. Please help. Thank


Modified by BlackRB at 7:59 PM 6/22/2009