Strange Intermittent AC Issue

[93_SHO_FL]

Ok, so one of my final issues with my 93 ATX is the AC. I have fixed just about everthing else now.

I took it to a local AC shop since it was blowing hot. I don't know much about AC systems.

They said it would need a new compressor, evaporator, hoses, and possibly accumulator, plus labor and recharge. They said this would be close to $1000+

I didn't want to spend that, so I decided to look at it myself.

I replaced the cycle switch, and noticed it was already converted to R134a system. So that saved me $50

I got a couple cans of the R134a w/ leak sealer. Charged it up til the clutch cycled. Then continued to charge it until it was at about 40-45psi while engaged.

It blows ice cold. Let it run for 15-20 min, then it disengaged and the heat turned on. Uh....WTF?

I turned car off, and back on, and ac worked again. I tried with the EATC as Automatic mode, and as MAX AC mode. Both had same result after about 20-25 min.

As soon as I shut car off, and turn back on, it's working again.

Could this be ambient temp sensor? Or maybe my EATC acting up? Bad relay somewhere?

I checked refrig pressure, and it didn't leak out. It blows ice cold for those 20 or so minutes...even when sitting at stand still.

Any suggestions are welcome. Thank you in advance!

 

[rubydist]

I would suspect the eatc first - try just turning the eatc off and back on, rather than turning the car off and back on, and see if that makes the a/c work again. there are lots of eatc's available, so that's an easy fix if that's it.

 

[93_SHO_FL]

Tried that. Didn't work. Have to shut ignition off and restart car. Maybe Microsoft wrote the EEC program...LOL...reboot.

I bought the EATC hard button from a forum member...I mean, it could very well be this, but without spending $80 on a brand new one, I guess I won't know.

 

[JRA2000TL]

Do this...when the a/c goes hot, get out and whack the a/c clutch with a broomstick handle or something similar; if it kicks on and the a/c cools, you need to remove a shim from the a/c clutch. My 95 did this same thing. The previous owner said the a/c was broken, compressor didn't come on, etc. Well the compressor did turn on only at a cold start up; so when it did turn on, I charged it with 134a and got the exact symptoms you have.

Once I removed a shim, my a/c worked and still works after about 8 months. If you need to remove a shim, you will need to remove the bolts off the clutch face and use a strap wrench or something to remove it. There are some deailed write-ups about it. Just pull the battery and battery tray out, and you should be able to get to it.

 

[93_SHO_FL]

Oh kick ass!! I will look at that ASAP!!

Thanks!!! Any idea why it turns the heat on though???

 

[JRA2000TL]

Oh kick ass!! I will look at that ASAP!!

Thanks!!! Any idea why it turns the heat on though???

Is it heat or just warm air b/c it's not blowing cold and it's hot outside? If it diverts to HEAT, ruh roah....blend door actuator. Do the EEC self test while you're at it. www.shotimes.com and go to care/feeding of the SHO. I forget the sequence but you push something like OFF and FLOOR and the same time, then within 2 seconds, press AUTOMATIC. It runs through a cycle and if your BDA is bad, it will give you an 02 code. If all is well, you'll get an 888. You'll then have to turn the car off and back on to reset the system.

 

[KyngofPop]

Is it heat or just warm air b/c it's not blowing cold and it's hot outside? If it diverts to HEAT, ruh roah....blend door actuator. Do the EEC self test while you're at it. www.shotimes.com and go to care/feeding of the SHO. I forget the sequence but you push something like OFF and FLOOR and the same time, then within 2 seconds, press AUTOMATIC. It runs through a cycle and if your BDA is bad, it will give you an 02 code. If all is well, you'll get an 888. You'll then have to turn the car off and back on to reset the system.

You press the cooler/blue button to exit the "test" procedure. Cycling to off does no harm but the control head and actuators could theoretically be damaged because they didn't get to cycle back to the predetermined 75* setting without exit first. Never happened to anyone I know but in theory.

 

[93_SHO_FL]

Cannot get it to run the self test.

 

[93_SHO_FL]

Ah ha got it. Running now...

 

[93_SHO_FL]

Crap. 02
How hard is that to fix?

 

[93_SHO_FL]

Oh jeez. I found this write up.

NOT a fun job!!!

Replacing BDA in Gen 2 SHO

 

[JRA2000TL]

Yeah, royal PITA; and yours is stuck to hot apparently...that sucks man. I got lucky. Mine is shot in the 89 but it's stuck on cold. I dropped the glovebox and unplugged the 7 pin/round connector because everytime I started the car, I heard a loud "click click click" behind the dash, so I unplugged the actuator so that it won't make that noise anymore. I will probably never fix this unless I find a good part cheap b/c I don't need heat down here. This was on my $300 project car anyway.

Shosource has the part but it's $$$$; like 200 bucks or something b/c it's obsolete. You can always find used, but it's one of those things where "do you really wanna have to go back in there to replace it again" if a used one fails?

 

[93_SHO_FL]

I actually found one for $27.29 w/ free shipping. We are going to tear into it in a few weeks. I have to install new fuel tank, pump, sender, etc first. More important issue for me at this point.

However, I'm just not seeing how the door actuator being bad would allow the AC to be cold for 20-25 min, then heat turns on. Then I shut car off, restart it, and it's cold again...baffled.

 

[JRA2000TL]

I actually found one for $27.29 w/ free shipping. We are going to tear into it in a few weeks. I have to install new fuel tank, pump, sender, etc first. More important issue for me at this point.

However, I'm just not seeing how the door actuator being bad would allow the AC to be cold for 20-25 min, then heat turns on. Then I shut car off, restart it, and it's cold again...baffled.

Oh, I forgot...it's the Gen I's that are the super hard to find expensive ones. You may have both a BDA issue AND an a/c clutch out of adjustment. Not impossible.

 

[93_SHO_FL]

Yeah, definately both worth looking into for sure. Probably go ahead and change heater core while I have the dash out...maybe.

 

[luigisho]

do it if the dash is already coming out.