What parts of the A/C does the ECU control?? - Honda Prelude Forum

AlexLude · 03-27-2004, 09:40 PM

Hey fellow luders,

Having some problems with my A/C.... I just did an OBD2 to OBD1 swap with my hondata setup and a couple days later.. A/C started acting up... Maybe its just coincidence, but I would like to ask your guys' opinions...

First of all, the air that was blowing out of the vents was really cold (even though the AC or fan is not on) i can feel really cold air (it not even that cold outside) blowing through the vents even if fan is off. And when fan is ON, I can see the vapor/mist blowing through the vents.

Just today i was playing with my AC once again to see why it was so cold.. the engine was on.. then i hear the whoooooooossh and some mist/vapor is released underneath my hood.. not smoke.. but more like vapor...

Near or under the AC compressor, there is this oily substance.. i'm thinking its the refrigerant oil that was released because there was too much pressure built up and no where else to go.

What do you think the problem is here?? The AC "froze" up and there was no area the pressure was to go and it just released it by blowing an O ring? man.. it's saturday nite and sunday the shops are closed.

i hvae to check it out on monday.

*** IS IT SAFE to drive around now with the A/C off?? i dont want to drive around if it would be bad for the car.... the thing is though.. i can hear the compressor turn on when my AC is on....

*** THE QUESTION at hand was.. Could a SWAP in ECU from OBD2 to OBD1 have affected the AC in anyway??? Please help me out!!! uggghhhh!!!

hope someone can help here...........

4thGenReady2Go · 03-27-2004, 10:19 PM

wow, i can't be of much help here, (sorry), but when mist/vapor is coming out of your vents with the A/C on, it just means that the A/C is doing it's job, and it can happen on warm days. As for the rest, that's for the next person in line lol. good luck.

AlexLude · 03-28-2004, 03:12 AM

bump for AC techies...

Scalifludesi · 03-28-2004, 09:57 AM

I don't think an OBD conversion could've mess up your AC system unless the ECU has gone beserk and caused the clutch in the compressor to intermittently engage and disengage but that wasn't your problem. It sounds like there's a short somewhere because you indicated that there's cold air coming out your vents eventhough the fan is off. About the oily substance on your compressor...sounds like an excess pressure build up and busted seals, either the O-rings on the connectors or the main seal on the compressor itself. If I were you I'd get that compressor tested ASAP to make sure there's no leak. In the meantime you can manually bypass the compressor from engaging by unplugging the compressor clutch relay or by disconnecting the wire that connects to the compressor clutch. I'd also want to get that AC thermostat and expansion valve tested (refer to Helms) because it should've manually disengaged your AC when the temps on the evaporator gets really cold in order to prevent ice buildup which in turn can cause an excess pressure buildup.

edit: when diagnosing, just tell the mechanic to check the vacuum and pressure levels on the system with the engine on because it is unlikely for the thermostat and expansion valve to fail (but it's possible). Replacing the expansion valve requires you to take the evaporator out and it's a PITA when mine crapped on me

G_Loc · 03-29-2004, 07:04 PM

Check to see if the compressor clutch is engaged all the time.

Just look at the center portion while the car is running. If its spinning, its engaged, if not, its disengaged.