gpracer,

I just responded to this post over on the a/c forum. Since you've already checked the fresh air door, I think aqua is onto it. You need to block coolant flow to the heater valve and see what happens. That's about the only thing left that could be causing this.

Don't get flustered. You've done a lot of work and still have high vent temp, but in the process you have learned more. Edison after trying zillions of materials for his light bulb filament was told that the latest burned out filament was another failure. His response was that it was NOT a failure, he had simply learned one more material that would NOT work.

Best of luck,

maybe we were all pretty stupid...and it will be the monovalve.

instead of freon being blocked.... and stopping cooling.... it is heat being introduced into the system, fighting the cooling.

This will be interesting.

__________________
1989 300ce 129k
( facelifted front,updated tail lights, lowered suspension,bilstein sports, lorinser front spoiler, MOMO steering wheel, remus exhaust,stainless steel brake lines). (Gone)

1997 s320 154k (what a ride). Sold with 179k miles. Replaced with Hyundai Equus

1994 e320 Cabriolet 108k



1972 280se 4.5 153k Owned for 12 yrs, sorry I sold it


[/SIGPIC]

What happened to the refrigerant that was in it?

Sounds like the monovalve to me - especially with the change during different driving conditions.

__________________
Jim

The window is clear.
I blocked the heater line also. (Forgot to mention that)
Airflow should be from either outside or inside car, through blower motor, through evap first, then on. So if the evap and low side hose is becoming warm from the air then it must not be getting the correct freon flow. I put in 38 ounces and the system acts like it needs 50. Like its starving for freon???
Is it possible that the evap or condensor are bigger than oem and it needs more freon? I kinda thought 180 was kinda low for the high side at 98 or so degrees? MB spec is around 250 high side for that temp. If I turn off the fans it will go to 400+ if I let it, so I know the compressor can do it.

lee,

It is really appearing that it is coolant flow that is causing the problem but the 124 car does not have a monovalve. It has a non servicable heater control valve.

I have had this failure before except when it happened the coolant flow went to max and the vent temp was probably literally 120 F. In that case the culprit was a bad CCU that was sending it no signal whatsoever. Since this one might be partially flowing it could be the valve itself OR it could be a failed sensor.

gpracer,

I just remembered. There is a diagnostic connector next to the heater valve. You can use an LED and a jumper wire to blink the led if any faults are detected. Most of these fault codes have to do with identifying bad sensors. If there were a bad temp sensor, it could be fooling the CCU into thinking that everything is cold, thus adding coolant flow to try and warm things up.

There is a very good post on here somewhere with a schematic for making a tester box for blinking this code. You can get by with an LED, but you will have to do some research to find that post and know what pins to short and what pins to monitor for the blink.

Good luck,

I have clamped off the hoses a few times to see a diff, and none. By the way, my valve was hung wide open when I first got the car last year....took it apart and the metal slug/magnetic plunger was all rusted. Wire wheel and some cleaning and it works like a champ.
The key here is that the evap, the first item in the air flow, is getting warmed by the air. The outlet line on most any car will still be cold even on high as long as the air at the ducts is cold. The line should be slightly cooler than the air at duct since the air wont have enough time to equalized with the evap. Which is why it blows colder at low speed fan. With mine the evap outlet is warm, no matter if the heater is on or not.
As far as I know, the only thing that will make freon flow change are....compressor function / and or speed (rpm) , the expansion valve, and the limit switch which will turn compressor off completely. Mine runs the whole time. Suddenly Im thinking the evap or condensor are the only things left.
Now I know why I dont do this for a living anymore.

http://members.aol.com/ajdalton7/ledtool.jpg
124.030 is pin 7 , if you have Cal.
Blk to 1 , Rd to Bat +, and odd color to #7 will get the codes
I have that info, if needed

Also , are you sure you had a COMPLETE evacuation.. air left in system will result in poor cooling , but still show good pressures
Check that sight goes through bubble stage til clear when started , and feel
both inlet/outlet of drier with your hand for any cold/sweating..

Well, I used my Robinair vacuum pump for 45 min, so its good. I have never messed with any codes on this car at all. There is no check engine light on.
Do you have the procedure including which plug, location, and codes?
I dont think there are going to be any codes since the compressor is on and the system functions somewhat. Maybe a "cant get cold enough" code, lol.
Ill get the parts from radio shack, just need to know what to do with them and where.

Is the car Cal Emmisions and does it have 8 pin diagnostc box?
. If you have a CE lamp , it should be Cal

It has a check engine light. Cal or not, not sure.

..and do you see 8 pin diagnostc box?

Ill have to wait till I get home from work. I rode the bike with 185.1 air.
No windows, 185.1 mph
Where is it located? Ill check tonight.

I'm not talking about the ecm or a check engine light. There is a connector next to the heater valve with about 8 or so sockets. One of them is for climate control, another for SRS and so forth. You will have to get the factory manual to get the code information but somewhere on here there is a thread with info about the led box and a schematic how to build it. It even gives Radio Shack part numbers.

I would search on Diagnostics or some such. It was at least a year ago.

All that said, now that you are saying that pinching off the heater hose makes no change in vent temp checking for a climate control code is probably not worthwhile anyway.

If you put 2.2 pounds of R12 in the system after evacuation and you have the heater hose blocked and still not getting low vent temps then we are back to a refrigeration issue or outside air finding its way inside.

When I read your post on the ac forum, I thought you had 25 degrees at the evap and considered the refrigeration system working. I really don't know where to go from here. There is a limit to what one can troubleshoot over the internet. That's not to say that I could do any better than you are doing if I had the car right in front of me.

Best of luck,

Its starting to look like an internally plugged evap. It got to 20psi low side and 25F at the evap with the a/c compressor on and blower motor out of the car completely, with the thermometer stuck right in the coils of the evap. I only checked one spot though, tonight im checking 20 points on the evap. Im thinking that only part of the evap may be getting cold, and it is easily warmed by the air since the area of cold would be so small.
I agree, I think this thread is a dead horse......Ill stop kicking it and take it somewhere if I cant finger it out this weekend.
Thanks for all the help though.....we are pretty much on the same page except Im actually able to work on it and you can only rely on what I post.

< >

The RShack part #s are on the pictoral I have posted.
The ECU module is pin #3 on the 8 pin Diagnostic box. It has nothing to do with pin #7 [which , as posted , is A/C module memory fault code storage].
CE lamp question was only posted cuz Ce lamp indicates car automatically has 8 pin diagnostic box .
The led box/chassis can be made of tool makers choosing.. my preference is a 35 mm film can for ease of assembly and availibility.
Exit wires out the botttom and mount sw/led in cap and pop the top on.
One can also use a clear film can and leave the led inside , as it can be viewed from the outside w/clear can.
Here are the Modules access pin numbers of diagnostic box
1-ground
2-NU
3-CIs
4-EDS [ Diesel systems]
5-ASD
6-SRS
7- A/C [ This is where you want to access A/C module w/tool]
8-NU

HOOK-UP :

Ground [ Blk connector in pictoral diagram] for the tool is plugged into pin 1.
Red connector of tool goes to Bat +,12V. [ these 2 give you the 12v to power tool]
Odd color connector from tool goes to pin #7 [ A/C module ]
With key On , press tool push sw and hold for 2-3 sec. Release and count flashes at led when they come back .
Repeat this procedure for each stored fault code until original number of flashes returns . That will be the full cycle [ code flashes are in numerical
sequence/order, so each will be higher as they are retrieved]
There are codes from 1 [ No codes found ] to 57 .
Write them down and I will tell you what they mean.
If you get a single flash , there are none.


**Tool Note
This same tool can also be used to go to any other pin on the diagnostic box to access any other flash codes , be it ignition or SRS or whatever..the only hook up change is the odd colored pin on the tool and which pin you put it in on the box..They all have code fault storage and led flash retrieve...