Ye Olde A/C shut off valve

[SVOboy]

So, I'm coming close to knowing how to do this in the most clean, all electrical way. Sure, it'll be expensive (for what it is, by itself) but if it is done this way it'll almost certainly be accompanied by some other sort of modification that would be well worth the expense by itself.

What I'm talking about is modifying the ecu. Basically, the information of doing all the hardware stuff is at my fingertips, and this concept has been done before, but not on the ecu I plan to modify, so that means I'd have to figure out what the hexadecimal code looks like for this and then track it down in a large file which basically looks like nonsense, but if I can, then it'll be rather simple to kill the a/c based on load.

[Matt Timion]

This weekend my car died a few times while idling with the A/C on. When I turned the A/C off it didn't die. I now that this can be fixed in other ways, but it seems to make sense to hook up a vacuum switch to kill the A/C when the car is idling.

This could also be done with a RPM activated switch to only have the A/C turn on above certain RPMs (or have it turn OFF below a certain RPM). This way the compressor wouldn't be turned on while idling, or during other times when the compressor is the most inefficient.

I'm trying to find a non-ECU solution as to make the application more friendly to all car owners, not just Honda owners.

[GasSavers_Diemaster]

your ecu is suposed to raise the idle to copensate the A/C. or if the motor is rpm too low it will shut off the a/c. instead of fabing up a soultion u should fix the problem. sounds like the system is wire impropaly.

[GasSavers_DaX]

In Hondata you can set the conditions for AC shutoff - I'm pretty sure it's RPM dependent though instead of load [MAP] dependent.

[SVOboy]

Yeah, I plan on using crome to switch of my a/c if my ecu ever gets support by it. All the tuning programs I know of do it normally at wot, but I think you can specify the load level.

[Matt Timion]

I've been lazy with this idea lately (mainly b/c I don't use a/c) but I really want to find a cheap vacuum switch and get this figured out.

At the very least it would be a cool addition to any car. WHile I like the ECU method of doing this, not everyone owns a honda so the solution would not be universal.

I think it would be cool however to be able to sell "economy chipped" ECUs for people who want them and this would be one of the features.

[SVOboy]

I figure it I ever get off my *** to learn how to do rom switching on a single chip I'll be able to offer this as a service where there is a physical switch you can stick somewhere in the car to toggle between the performance stuff and the economy stuff. It's extremely possible, and has been done a lot, I just need to get around to it.

[GasSavers_DaX]

I don't know about doing it on the same ROM, but if you wire a toggle switch into the J1 jumper on an OBD-1 board, you can switch between the stock program [J1 open] and a program burned on a ROM [J1 closed].

[SVOboy]

That's true, but you can switch programs on the same rom. Some people even buy the 32 pin 1 meg roms and put for programs on there, but that gets annoying with all the wires coming off the extra pins and blah blah blah.