Strange Idle Flux With A/C

[toyotajake37]

Just picked up a "new" Tercel the other day and I love it. Only noticed one problem so far. After driving for a while and letting it warm up when I come to a stop and the engine is idling it will bounce between 600 and 1000 rpm. Every time is changes I hear a clicking noise coming from under the passenger side dash. It is in a very regular pattern and changes about every second. The clicking sounds kind of like a relay going on and off. When I turn the A/C off the problem goes away and the clicking stops.

Any ideas on how to fix this would be great. It doesn't seem like it's going to kill the engine at any point, but I would rather fix it than deal with it.

Thanks

Jake

[ARCHINSTL]

Welcome to the Club!
Sorry I can't help with the AC query (mine's dead), but while anecdotal answers are always best - did you scan the AC section of the FSM available here? I perforce barely scanned this section in my own FSM, but it seemed like there was some note about the AC having a cycling effect on idling...
I note your cars - That Land Crusher should be worth some BUCKS! And jetswim will swoon over your TWO Westies!
Tom M.

[toyotajake37]

I checked in the AC section and all I can see that mentions a flux is that the RPM should go up when it's n, which it does. I did notice that there are a few switches and something else that are part of the AC system behind the glove box, which is where I hear the clicking, so that's maybe a place to start. Today I noticed that at idle as well when it is not doing it constantly if I rev it just a tiny bit it will suddenly drop to 600 rpm, then go back to 800 or so just once, and I do hear the same clicking noise. I'll have to start troubleshooting tomorrow.

BTW the Cruiser is sold, and the hightop westy will be sold tomorrow. Then I will only have 3 vehicles, but at least I've got my new Tercel. I'll post up some pictures and more info on it in the gallery tomorrow.

[Don Jorgensen]

There are 2 positions on the A/C on/off switch. Push in once and it is on Green color economy and will cycle the compressor on and off each time the idle responding but it shouldn't cycle as much as you mention. Push in second time and it is on Blue color and compressor is on all the time with no cycling.

[toyotajake37]

It does it in both ECONO and A/C modes. It hasn't done the repetitive cycle for a few days. It does seem to ALWAYS cycle when I am coming to a stop though and the A/C will not work when I am at a stop. Works great as soon as I start driving again. So I have a few more questions.

It seems that the problem is that it is just cycling too much and not working at a stop. Could this have to do with the switch that turns the compressor on/off?

Also, I believe if it is running out of coolant it will cycle more often? Is this a possibility, and if so should a recharge be a good first step at trying to resolve the issue?

Any other ideas/insight would be helpful. I'd like to try and fix it before summer is over so that I don't jsut forget about it and have to deal with it next year.

Thanks for the help so far.

Jake

[Petros]

I seem to remember that there is a switch that is supposed to raise the idle speed when the AC is engaged to keep it from idling rough or stalling. I would guess it might be there, check the manual and the wire diagram to search for this circuit and check that system out.

Good luck.

[ARCHINSTL]

The FSM here has a lengthy section, albeit with some very dark photos of the system (I don't profess to ANY knowledge of the system). When the AZ site comes back up, you might check it for photos of the system; I believe it has better photos, but I do not remember.
Something you might consider, though...I dunno how hot/warm Davis gets during the Winter, but if you are low on R12, with what it costs nowadays and the fact that the "homeowner" cannot buy and install it like the good old days - if you even think you have a leak - I'd wait until it gets warm next year to refill it. I did this with the AC on another car a few years back, just as you mentioned, to avoid dealing with it in the Spring - well, it leaked during the Winter and I had to get the full R12 recharge plus, of course, have the leak fixed.

If your hood emissions sticker is still intact, it should show the location of the actuator. The vac diagrams I posted in the Repair Forum are, as noted, for Federal cars and the AC actuator is clearly marked. Here again, though, look at the FSM here or on AZ, and the CA emissions diagrams are available.

There are also several threads here on R134 conversions, both the quickie method and the "approved" method. Both procedures may be worth a price comparison if you have to buy R12 - it ain't cheap and again, a real tech has to install it, per the law, so there will be a labor charge...
Tom M.

[takza]

Also, I believe if it is running out of coolant it will cycle more often? Is this a possibility, and if so should a recharge be a good first step at trying to resolve the issue?

If you check the sight glass you will probably see bubbles which means freon loss. Mine does this cycling thing. I could add some freon to make it work OK. Belts off now.

With my AC I needed to keep it set on COOL all summer and just turn the AC on or off...trying to blend between cold and hot is not a good thing to try...causes problems.