noquacks

People,

Civic 2001 EX, evacuated system, added the right weight of gas, and compressor does not even come on. Psi on low side shows a weird 10-15. What the heck? Even with bad comp shouldnt the psi register up there?

Also, would like to check my relay- how do i do that?

I will do more checks today to add more bits of info. If anyone has any tips on what else to check for please let me know, I appreciate it. I need to verify a bad comp before buying a new one.

ezone

What weight is that exactly? How did you measure that weight? "Gas"?


Was the compressor running when you read this 10-15 PSI?

If the compressor was NOT running, and this value is accurate, the AC system is prevented from turning on because of insufficient pressure (low refrigerant charge).



I've posted in about 15,000 AC related threads, search

noquacks

A Big thanks, Ezone! I knew someone would question my "exact" weigh of "gas". The word gas is way shorter than refrigerant, and actually relevant, as r134a at ambient temp is a gas. Of course, under pressure, it is a liquid, no mystery here.

I added the amount specified by the manufacturer- Honda, printed right on the sticker on the car's frame- 17.4-19.4 oz. I shot for about 19. I weighed it in with a 2 decimal point scale, laboratory grade, calibrated, not that we even need that accuracy.

The comp was not running- thats the mystery. Why was it not running with ac switch on, fan on high, system charged up with the exact weight of "gas"?

So, how can it be that the system had as you say "low refrigerant charge" when I introduced the right amount? I could have easily blasted in an entire 2 can's worth (24 oz), but I weighed it on a 2 place gram/oz scale. Shouldnt the comp have come "on"? Thats why Im suspecting something else like the relay.

Oh well, Im still searching for clues.......

I appreciate your support in my dilema.

ezone

If you put more than a pound of refrigerant into the system yet the pressure gauge only shows 10-15 PSI, either the gauge is wrong, your charge is wrong, or you must have a freekin huge leak.


The AC system cannot run if there is less than (about) 30 PSI in it.
You could check the pressure switch for continuity (or open) to see if the system has sufficient pressure to begin operating?

noquacks

Thanks again, ezone. Youve given me hope. You make sense and thats why Im so puzzled.

I will check the guage on another car with "good working " ac to "test" the guages.

noquacks

Just tested again, and guages are good. Engine on, ac on, fan on, low side psi is 8, and high side is 160. Static psi before engine on was 110 (on both guages). What does this mean ezone?

ezone

Your first post said your compressor didn't even come on, and I questioned that in post #2. Your pressures on your last post indicate the IS engaged and running.

With gauges connected, rev up the engine to about 2000 rpm and note what the pressures do

Also
What's the vent temperatures now?

noquacks

Thanks, ezone, but I just said in my last post that the psi was a very low 8, not that the comp was on. I didnt hear the comp cycle at all. All I reported back was the psi. But in your opinion, should the comp be working for the high psi to reach 160? Is that what you mean to say about my comp to be working/engaged, cuz psi's are 160 on high side? I may be confused, but comp did NOT cycle at all. One can hear it easily- kicking on/off.

Vent temp is ambient- 85 or so. Same as outside.

Sorry for the confusion and all, e zone, but so far youre the only one Im depending on. Thanks.

ezone

The pressures say the compressor is engaged and running. It wont cycle unless the temp in the evaporator core drops under about 37F.

Now you need to figure out why the air isnt cold. Feel the temps of the two ac pipes at the firewall

noquacks

OK, just checked again and heres what I got: low side psi is 45, high side is 300. Outside temp is 90 (hot here!). The comp did NOT stop - did not cycle on/off, the clutch was turning and never stopped in the 15 minutes I observed it. The psi's hardly ever changed either. 45 psi on low side steady.

The vent blew cold air initially for say, 2 minutes, then quit, and blew just very slight cool air, thats a bad sign. Every say, 4-5 minutes I would get some COLD air which lasted only for about 1-2 minutes. I reved up the engine to about 2000 rpm, no difference, car still blew warm air out the vent (about 85-90 deg).

Oh- this should be big- all the while the comp never stopped turning and every 3-4 minuted the entire engine shook violently/crazy like I never seen before for about 30 seconds. Like the ac clutch was struggling or binding. Thats all I can figure.

Any ideas ezone?

ezone

Seems a bit high, though I don't have enough info to ponder that much further.

Were these pressures read while the engine was idling?
What were the pressures while it blew cold air?
What were the pressures when it quit blowing cold air?
What were the pressures while running at 2000?

(Oh, this is important) What were the pressures at the time the engine seemed to be struggling shook violent/crazy?

During each of the above, what were the temperatures of the two AC pipes that enter the firewall?


Are BOTH radiator fans operating?
Both are pulling air in the correct direction? (not wired backwards)

Are the condenser and radiator fins clean, free of bugs and road debris? You can see light through the fins in all areas? (place a bright light in the fan areas and look through the bumper openings) Condenser fins not all bent over from rocks and road debris (blocking air flow)?


If you run the AC and spray the condenser with a garden hose to cool it off, what do the pressures do and what does the vent temperature do?

Wash out the radiator and condenser with garden hose from the fan side, let water push bugs and debris out toward the front.

Is the heater water valve completely turning off water flow through the heater core when HVAC is set to cold?

noquacks

OK, E, looks like I got homework to do- I will get an assistant to get answers to all your questions above. And I will clean the condenser. Give me a day or so.........

Thanks

noquacks

Ezone,

I ttook thecar for a ride to buy vegetables and car ac work great!! Drove it for 7-8 miles. Why? How? When? Who knows. Maybe the gas had to 'settle" or ferment(?). I dont get it. After so much work and trouble and WORRY that I might have to buy and install a new comp. Whew.

Thanks for all your support, Ezone!

ezone

No.......but I sometimes wish something like this were possible LOL


Continue monitoring its condition, update if it seems broken again.

noquacks

Sure thing, Exone! For now I can breath easily. But it WILL "break" again in the future. Then I will be back! I know it has at least a very slow leak, which is no big deal. Thanks for all your support! People like you are much appeciated!!

noquacks

OK, after a week of decent cold ac, not it quit entirely. Back to the drawing board- it was too good to be true.

Heres what I got just now:

static psi is 110 at about 88 degrees F
Engine on, ac on high, low psi is 0-2psi, High is 200
After engine running for 5 min, low = 5 psi, high 200 still

Rev to about 200 rpm, low = zero , slowly going DOWN to negative 5 (5" mercury vacuum??) huh??!! high psi = 200

Air in cab is about ambient to just slightly cooler, barely noticeable. Suction line in engine bay is very cool to cold to touch, but not ice cold. Do not have a fancy temp apparatus to check temp on that aluminum tube- just my hand, going on experience in the past. Colder at the firewall, at the orfice tube "box", then warmer as it goes to the compressor.

Any ideas, people? Gotta do something soon, too hot here in FL.

Thanks

ezone

Sounds like you either have a blockage in the system, or the expansion valve is sticking closed.
Since you say it was working for a while....I'll GUESS it's a sticking expansion valve
(or possibly moisture in the system from improper procedures, causing the valve to freeze).


If you wish to rule out or check for other possibilities, you're going to be checking temperatures of parts of the system. Really you should read some theory of how an AC system is supposed to work first: http://home.howstuffworks.com/ac.htm



Make it act up, and you start feeling the system with
yes your hands (be careful don't get burned), you will be feeling for a major temperature change comparing inlet and outlet of a given component or pipe.

For example, If the condenser is restricted internally, the inlet pipe will be hot and the outlet pipe would be cold. (A temperature drop of 20-30 degrees in the condenser is normal on a working system, but 150 degree drop is not normal)

If the drier is clogged, there would likely be a big temperature drop.


The big temperature drop is supposed to happen as liquid freon passes through the expansion valve, changes states to a gas, and goes into the evaporator core where it absorbs heat from the interior of the car. If the state change occurs elsewhere, in the system that's a problem.

noquacks

Makes sense, ezone. I will follow up with more tests, and decide what to take a chance on- probably easiest to start with expansion valve/drier. I will check the temps of condenser just in case.

So, can we at this time say for sure that the comp IS OK because it is compressing the high side?

ezone

Without being there to check it myself, my guess would be a bad expansion valve.

Compressor is working at this time.

noquacks

Great, ezone! I know there is no 100% for sure diagnosis, but I too believe the valve is at fault. Cheap and easy to replace. Low risk. I will let you know what happens!!

ezone

Easy?

In order to reach the expansion valve you will have to extract the evaporator housing from the dashboard.
I doubt the valve can be replaced from the engine compartment.

noquacks

Uh- Ohhhh, I viewed that "block" from the engine bay. But I think youre right I need to remove evap from inside cabin, but at least I dont have to yank the entire dashboard, based on the instructions I got.......

noquacks

This is the valve:

http://www.ebay.com/itm/Global-Parts...-/131871259463

ezone

Right...Remove fan housing, PCM, then you can reach the evaporator housing to remove it.

noquacks

Ezone,
Update: Removed the evap and popped out the evap core and immediately noticed small 2mm or so beads clogging the lower orfice (high psi line?). You were right, ezone!!

Dismantled the exp valve and removed the small 2mm beads of what has to be dessicant stuffed/jammed into the lower (smaller) orfice in the exp valve. Also visible from inside cab looking into the lower line (high psi line/narrow one) beads were collecting there as well. That is the liquid line going to the drier, then proceeds to the condenser.

Im hoping/trusting that if the dessicant travelled to the exp valve then that line section ONLY is polluted with beads, right?


So, how do dessicant beads get in that line? How to flush out? With solvent and a compressor? Suction line had no beads visible, do I assume there are none there?

Do I blow out the condenser too or just buy new?

ezone

Beads? Well that explains why it was doing this.

Sounds like you're right about the dessicant, that means the receiver-drier is bad, the dessicant bag inside it has come apart. ....

gonna need to replace the drier and you're gonna need to do some cleaning (purge) the line from drier to firewall to get the stuff cleaned out, and check if the stuff made its way into the evaporator core, and purge a little more just to make sure.
(purge both directions, multiple times)


Parts stores may sell AC flush kits which used to be a jug of R141b and a vessel you could fill and pressurize, with a hose and nozzle.
You'll have to see what's available in your area.




The orifice of the expansion valve is extremely small, so I sure hope nothing made its way through into the evaporator core, but you better check it.
You have the evaporator out of the car: Flush the evap core into a clean towel so you can see if any garbage was trapped in it. Towel should catch any solid debris that comes out.


Flush the line out from drier to firewall. You know it's got beads in it.

Disconnect the line from the bottom of the condenser (to drier) and flush, just to make sure nothing went backwards through the system. If stuff went backwards into this line, you might want to take the top line off the condenser and flush the condenser out.

......REPLACE the receiver-drier unit, and REPLACE the O rings on every line and fitting you take apart. (O rings for AC and R134a are special, parts stores may have a big kit with a large selection to choose from....most if these kits have green colored O rings)


You will need some fresh PAG oil too. Flushing this stuff will remove oil from the system. If you don't replenish the oil in the system you'll ruin the compressor.

noquacks

Good deal, ezone. Much work to do, but looks like we got it !! Great diagnosing (from both of us(?)).

Oh- do I have to remove the big bulky stupid plastic front bumper to remove the drier and access that area?

ezone

IDK, does it look like you can remove the drier as is?

You'll probably have to remove the bumper cover in order to disconnect the line from the bottom of the condenser for purging.
Most bumper covers can be removed in just a few minutes (with the car in the air on a lift)

noquacks

OK, sounds good. Ill try it out and if I need to remove bumper no big deal. Thanks, Ezone!! I will let you know what happens!

noquacks

Got the drier out from the top with no need to remove bumper or front tire/splash shield. Anyway, after I purge/clean out the liquid line and evap, how much PAG oil should I add to each component? Also, the drier?

Also, can I add ester oil even if there is some pag in there? I understand ester is compatable(?)

Thanks.