Topic: A/C and the ECU ??

[mldave]

On my 86 Toyota 4x4 2.4 EFI that used to have a turbo engine,are there any pins on the ECU that effect the A/C.This rig never had A/C before it was added last year.Was changed over to the 134A,no leaks,but dosen't really get very cold.Right now the A/C amp board is bypassed as the new part is pricey.Would not having a working amp board effect how cold the A/C gets?

[1980yota]

The only things that effects how cold the a/c gets is the compressor, the effective surface area of your condensor and evaporator, and the amount of charge in the system.

Does it get colder when your going down the road as oppose to idling?

[mldave [OP]]

1980 Yota,everything checks out with my mechanic..don't notice much difference when idling or on the road.Thanks for the reply.

[Snowtoy]

Did you use used R12 oem equipment, or R134 equipment? 

R134 operates at a higher pressure, making R12 equipment work harder and less efficiently.  I know using the R12 equipment in my '90 and R134 refrigerant(conversion kit)  It never cooled all that well, even when properly filled by an A/C shop.  I went with an alternative refrigerant called Maxi-frig, it cools much better w/the R12 equipment.

[1980yota]

1980 Yota,everything checks out with my mechanic..don't notice much difference when idling or on the road.Thanks for the reply.

If everything "checks out" then you shouldnt be having a problem. Either the referigerant level is not correct or the compressor is not working to its full potiential assuming your condenser and evaporator dont have any contaminants such as dirt or leaves that would be decreasing their effective heat transfer areas.

While I agree R-134 does not cool as well as the old R-12 I have converted numerous vehicles to R-134 and have never had one that didnt get cold enough for th customer. If you think its not cold enough then there is something wrong with the system regardless of whether it has R-134 or R-12 IMHO.

[mldave [OP]]

Snowtoy,I didn't put the A/C parts in,but probably has the the R-12 parts and was changed to accept the 134 gas...1980Yota,drove it around 15 minutes this morning on a cloudy day about 77 degrees outside here in the motherlode of California at 9:30Seems to be quit a bit cooler riding than idling.Too bad you're not in this area and could check it out for me.Right now the A/C amp board is bypassed with a jumper wire in one of the plugs.Will this burn out/seize up the compressor if used continuosly?

[Tofudude]

if its happens at idle only then try getting an electrical fan...my dads landcruiser had that same problem...once with swapped in an electrical fan the AC blew the same from idle to cruising.

[1980yota]

I agree with the above, if it does not cool when idling then either your condenser is stopped up with dirt and debris or your clutch fan is not engaging to pull enough air. Does the truck run hotter than normal on the temperature gauge with the a/c on and idling? Also, if you have any kind of thermometer you can stick in the vents see how cold the air actually is. Anything 30 degrees and lower from out door ambient is good.

Having the circuit board bypassed will not burn the compressor up as long as it has oil with the refrigerant in the system. However, by bypassing the circuit board the compressor will not shut off in the event that the refrigerant leaks out and the pressure gets too low. This will damage the compressor. Also, the thermistor is regulated by the  circuit board as well. The thermistor shuts the compressor off if the evaporator gets too cold so that it does not ice up. Once you get everything lined out this could be a possibility especially on cooler days and when running in recirculation mode.

[mldave [OP]]

1980yota,no rise in temp on the gauge when idling.Taped a thermometer to the passenger side vent and drove around for 20 minutes.The air out outside was about 77 degrees and the temp at the vent read 51 degrees.

[1980yota]

That is a pretty good temp difference for the older style systems. It might could be a little better if the refrigerant level needs some tweeking or if the condenser needs to be washed to get dirt and debris off. Sounds like though your main problem is idling which would be a fan clutch issue.

[mldave [OP]]

Thanks for the info fellows....