puffthomas

H-T,

My friend at work has an Acura 2.2 CL and has a problem. I told him I'd post this on H-T and find out if anyone could help him out. Let me know if you have any ideas. Thanks!

Ok, I really hope someone in here can help me because I'm about to go crazy with this AC problem. Long story short, a tree fell on the windshield of my '97 Acura 2.2 CL (pretty much a Honda Accord). The glass from the windshield put a hole in the evaporator. The loss of oil made the compressor blow.

So, I replaced the compressor, evaporator, and drier about a month ago and had the system evacuated and recharged by a professional. After a couple of days, the air conditioner started to make a loud THUMP sound that I can hear and feel. Low and behold, the system is shutting down on its own and trying to restart itself over and over again. After about 5 attempts to restart, it finally stays running for about a minute or 2 before it repeats the whole thing over again.

I did quite a bit of troubleshooting and can not pinpoint the problem. 1st, it is not the evaporator temperature sensor because I bypassed it completely and it still shuts down. So, obviously it is not shutting down as it normally would to save the evaporator from icing over. The only other part of the system I know of that would make it shut down is the pressure sensor switch. This makes sense too because the THUMP seems to originate in that area. The problem with this is the pressure seems fine. I even let out some pressure to see if it made a difference (to about 24PSI low side) and then added it again up to 40PSI low side. I know these are extreme highs and lows but I thought if I went extreme, I would get an idea which one was causing the pressure problem. No difference at all (and I don't have a high side pressure gage)...

So my thoughts are either 1) the thermal expansion valve which I did not replace with a new one. I'm not really sure what it does but could a bad one cause these symptoms? 2) The pressure switch itself is bad? 3) Or, the remanufactured compressor I bought is bad.

Any ideas would be greatly appreciated! I had to spend $70 for a shop to recharge and don't want to keep wasting time and money. Plus its really HOT out!!!

alpine_hikr

A loud thumping sound may be caused by excessive pressures in the system causing the pressure relief valve to operate causing a loud *** noise as it releases pressure. The expansion valve wouldnt cause noise becauase its main job is to meter the flow of refrigerent into the evaporator depending on heat loads. Its other job is to suddenly expand the high pressure liquid into a low pressure vapor as it enters the valve.

Let me know what your pressures are in the system and I could give you some diagnosis steps. You say taht you had 24 and 40 psi for the low side? Thats high. The pressure on the low side should be between 17 and 23. On the high side there should be between 120 and 140 or more depending on heat loads. Again let me know your pressures for the low and high side just after the compressor kicks off and I can prolly help ya out. I just got done taking A/C and electrical this quarter in the honda pact program so its still fresh in my mind. Good luck

ajtcl

There is also a compressor relay. If this has failed, your compressor will either not com on, or it will cycle unwittingly. This could be part of your problem... Was the A/C on this car working without issue before the tree fell on it? Just curious.

puffthomas

Yes, it worked before the tree fell on the car.


My friend just sent me an e-mail and this was his response:

"Speaking of which, can you write back in the forum that I let out a lot of pressure in the lines end stopped at 21 low side and about 160 high side. They seem to be holding pretty steady and the AC has yet to kick off. It seems to be fixed! "

Thanks to the guy who responded to this post earlier. Good job man!

alpine_hikr

Glad it worked out for ya. 160 is a little high for the high side pressure, I would reccomend getting the high side to around 140 tops.