Since I have had my 2000 Civic SI engine swapped last summer, the 2 A/C lines that connect to the compressor were unhooked for like a day. Nothing else in the system was unhooked. And prior, the A/C was working fine/blowing cold air before the swap.

Since summer is around the corner, I am going to attempt to vacuum/evacuate my A/C system with a 3.0 CFM vacuum pump with manifold gauge set and re-charge it this weekend with some new R134a.

Currently, when I hit the A/C button, the condenser fan comes on but nothing else happens, the compressor does not engage. I assume because there is no pressure in the system.

With my swap, I am running a JDM ECU (P73-013 from a 1998 JDM ITR) and was wondering if JDM ECU's are compatible with USDM A/C systems in terms of sending signals to the compressor to kick on when the A/C button is pushed?

 

Anyone?

 

There's no freon in system, the low pressure safety switch won't allow the compressor to kick on til there's enough in there

 

blacktibby is correct. There is a low pressure and a high pressure switch on your AC, although the high pressure switch will not prevent the pressure valve on the compressor itself to rupture, so be sure you have the right amount of freon. Pull a good deep vacuum, 50 microns would be ideal. Also, check your service manual, but i believe your car's system takes 22 ounces of r-134a. Be sure you get two 12 oz. cans and put them in, you should be sitting perfect. (you'll still have deminimus loss, plus you won't be able to get every ounce out of the can)

 

and yes the ECU will perform the exact same way your compressor. It acts the same with sensors and components, minus component differences (the issue i'm having- 5 wire o2 to 1 wire o2). speaking of JDM ECU's, you know where to get them? My P70 from my Vtec ZC swap is running in limp mode, cant seem to find JDM ECUs anywhere.

 

Thanks for the insight. I bought 2 12oz cans of R134a yesterday. I will update after I attempt to vacuum and re-charge.

 

So I vacuumed my system and re-charged. I ended up getting my system to blow 40 degrees. At idle, the low side pressure fluctuates between 20-37 psi during the compressor cycling on and off. The high side fluctuates between 130-150 psi between cycles. The high side seems off as around 200 psi should be the norm from what I have read.

However, if I hold the throttle at like 1.5-2K RPM, the high side fluctuates between 150-200 psi while the low side fluctuates between 15-30 psi.

Overall, my pressure on the high side seems to be on the lower end but my system blows a cold 40 degrees. I am not complaining. I am not sure what is causing the below normal pressure on the high side but at least both high and low side pressures are not in the range of damaging the compressor I assume.