Str8Down

I notice on my PFC that my AC keeps turning on and off for no reason (as far as I can tell) while just driving down the road. Seems to be worse the hotter it is outside. Anyone know if this is a sign of low freon or something?

rynberg

Welcome to owning a PFC.

Str8Down

So you think it's actually the PFC with the whole "resistance in the switch" deal CAUSING my problem? I mean, the compressor turns on and off like every 3 sec. I thought if you had the resistance in the switch problem, your ac would just not work at all on certain settings? Plus, it used to do this pre-PFC. But it only did it back then when the car got really hot. Like idling in 95+ weather with the ac going and not moving an inch.

ZeroBanger

Str8Down,

Its a power FC problem that 90 pct of power fc owners have. If you put your stock ecu in, the problem goes away. I have replaced the blower switch and it worked for a month and then quit again. 1 was the only setting that alway worked. The other settings would go in and out and eventually stop working all together.

I had my entire system checked out for voltage drop and it appears to be isolated to the power fc itself.

I decided to bypass the ecu and use a boost switch to turn the a/c off during heavy acceleration.

so now my ac works on all 4 settings and is ice cold.

Str8Down

Zero, so yours did the cycle on and off thing every 3 sec or so? I have read many posts about it not working at all, on certain settings, but didn't find any posts that matched my exact issue.

J.S.J

Just a though, install a pressure cycle switch and wire it to the compressor. Set it to shut down around 20 psi or so.

rynberg

If you experienced the same problem with the stock ecu, then yes, it's possible that the system is low on freon.

apexkw

i have the same problem as str8down. every 3 sec on and off. huge drain on the motor. i have replaced the evap, condenser, checked for leaks, and the thermo switch. freon level is full. but still it wont go away and i cant check with a stock ecu cause i sold it.

alberto_mg

or overfilled with freon. happend to me.

ZeroBanger

When I first got my power FC, my ac would work on 1,2 and 4 pretty sold. 3 didnt work. After my engine got replaced position 4 would cycle on and off for about 4 months. 4 would eventually stop working, then 2 started cycling on and off and eventually 2 stopped working.

When I replaced the stock switch all 4 settings worked for a month and then the cycle started again, the ac would cycle on/off on all settings except 1 (1 always works). then they all stop working except 1.

Just do what I did, its an easy, cheap fix that works. It will never cylce off, infact the ac will get so cold you will freeze.

The power fc has a voltage drop, possible grounding issue that causes it to cycle on/off. Eventually resistance or something else causes it to not work at all.

potatochobit

iTrader: (1)

there are also 3 preassure switches. there is one behind the glove box near the evaporator that usually goes bad. the a/c will get cold when you first start the car, but when the compressor cycles, goes off, it wont come back on. then it gets hot.

ZeroBanger

His car is likely power FC related and has nothing to do with the a/c system in the car.

Str8Down

Actually Potato, that sounds like my issue. Becasue when you first start the car for the first 10 min, I watch my PFC and the AC doesn't cycle on and off, it stays on steady, and it get real cold in the cabin. Then after the car gets hot, it starts cycling on and off. So what do I need to do? What does that pressure switch do?

Str8Down

Can you tell me where this sensor is, and how to check it? Does it show up on my PFC sensors?

Str8Down

potatochobit???

REAmemiya FD3S

zerobanger, what exactly did you do, and how did you do it? do a quick write up so the rest of us can try it out and see if it helps us. or if there's already a thread on how this can be done, post the link. thanks

potatochobit

iTrader: (1)

ok its really easy to test. first you have to go under the glove box and find the evaporator box. there is a little black switch. you want to jump it. just get a piece of wire, and by pass it. if your A/C works, then that was the problem. if not, it is all PFC related as everyone says. but you say your A/C still doesnt work with the stock ECU so it could be this also. you can also test the switch with an ohm reader.

Str8Down

Can you be more specific as to where the switch is? I looked under the glove box and didn't see any small switch.

Str8Down

Potato?

airborne

Random note, there is an AC cut off system in FDs. If it senses full throttle it will shut the AC off for 8 seconds. If water temp gets above 243F it will shut off until they drop below 239F. Or if the car has just started it will shut down the AC for 8 seconds.

Maybe that is going haywire, page F-140 in your shop manual.

airborne

oh and here's the link to how Zero's AC switch fixed his problem

https://www.rx7club.com/power-fc-forum-47/ricks-rotary-performance-diagnosed-my-power-fc-ac-%2Aresolved%2A-279453/

ZeroBanger

It fixed it for about a month I had to hook my pressure switch to my ac and run the ac off a switch to finally fix the damn thing.