A/C has me stumped

[siscofarms]

06 liberty CRD . At a idle the A/C works good . Rev up engine the high side climbs to near 300 and I'm assuming the switch is kicking the ac off and it will cycle every few seconds but won't keep cabin cool . I'm assuming a restriction which is why I have replaced the line with orfice tube . I'm starting to think evaporater may be problem . Line going thru firewall is cold . Line coming out and to the dryer , which was replaced when I did new line , is not . Just outside temp feel . Am I hopefully wrong or could the condenser be the issue ? This is a first for me . I mainly mess with tractor A/C , basically the same but ,,,, ?

 

[DadOSix]

Was there a compressor failure in which crap could lodge in evap or condensor?

It was initially sounding like a slogged receiver (oil over saturated) but I am thinking your post says that you replaced that along with the line.

 

[KJowner]

Have you been using refill tins?

 

[siscofarms]

Compressor was replaced in the spring but was for a bad clutch . Shes got nearly 300,000 miles and had never had one so replaced the hole unit . Worked fine until a month ago , or until it got HOT.
As far as TINS assuming you mean cans then yes , 12oz cans .
If Im wrong about the high pressure being high meaning a restriction in the line , please let me know .

 

[DadOSix]

Compressor was replaced in the spring but was for a bad clutch . Shes got nearly 300,000 miles and had never had one so replaced the hole unit . Worked fine until a month ago , or until it got HOT.
As far as TINS assuming you mean cans then yes , 12oz cans .
If Im wrong about the high pressure being high meaning a restriction in the line , please let me know .

Need more that just hi side.

Since you are versed in tractors - i guess this is over simple but:

At engine off, not running - lo and hi should equalize and in the case of 134, read about ambient values - so 70F would show 70 on hi and lo side.

When the ac is running, lo side is the suction side, so it fluctuates with rpm and load. Lo side ‘pulls down’ to 30-40 as the compressor is engaged. It will drop lower as rpm increases and compressor stays engaged.

 

[KJowner]

Tin cans... guess that's the language difference.
A lot of them come with oil or leak stopper that can overload / block the system, I'm not a fan of putting them in anything I plan on keeping.

 

[siscofarms]

Need more that just hi side.

Since you are versed in tractors - i guess this is over simple but:

At engine off, not running - lo and hi should equalize and in the case of 134, read about ambient values - so 70F would show 70 on hi and lo side.

When the ac is running, lo side is the suction side, so it fluctuates with rpm and load. Lo side ‘pulls down’ to 30-40 as the compressor is engaged. It will drop lower as rpm increases and compressor stays engaged.

Thanks for the info . But there is where the problem starts . Engine off they are equal at around 60 psi . At idle , low side is 45-50 , high side is 240-260 . Not even under a load or anything , just rev up engine to 2000 rpm it kicks out and starts cycling just enough to know that it is , low side will pull down towards 40 and high reaches almost 300 before it kicks out . will not stay engaged long enough to see what happens from there . Buddy of mine has suggested ac module but if I remember right its envolved with the transmission ECM and would rather make that a last choice .

 

[siscofarms]

Tin cans... guess that's the language difference.
A lot of them come with oil or leak stopper that can overload / block the system, I'm not a fan of putting them in anything I plan on keeping.

No oil and absolutly no stop leak . The compressor I replaced in the spring came pre-oiled where I didnt have to do any of that .
Thanks for the help

 

[DadOSix]

Thanks for the info . But there is where the problem starts . Engine off they are equal at around 60 psi . At idle , low side is 45-50 , high side is 240-260 . Not even under a load or anything , just rev up engine to 2000 rpm it kicks out and starts cycling just enough to know that it is , low side will pull down towards 40 and high reaches almost 300 before it kicks out . will not stay engaged long enough to see what happens from there . Buddy of mine has suggested ac module but if I remember right its envolved with the transmission ECM and would rather make that a last choice .

I stole this from the cummins forum

According to my notes that i have on A/C pressures ill list all ive got so more people can benefit from this.

Low Side Low High Side Low
- Low Charge
- Metering device stuck shut
- Kinked liquid Line
- Too much oil

Low Side Low High Side Normal
- Liquid line is kinked
- Plugged metering device

Low Side Low High Side High
- Restriction in condensor
- Overcharged
- Metering device plugged

Low Side Normal High Side Low
- Low Charge on a variable displacement compressor

If BOTH SIDES are mormal and still no cold air
- Blend air door
- Air in system

Low Side Normal High Side High
- Condensor is not getting enough airflow
- Restriction on high side

Low side High High Side Low
- Faulty compressor but make sure its running (in other words is the clutch locking)
- Low charge

Low Side High High Side Normal
- Metering device stuck open
- Variable displacement compressor stuck in low pump mode

Low Side High High Side High
- Overcharge
- Lack of condensor flow

 

[siscofarms]

Im coming to the conclusion that the ecm is my problem . All I have been told is that you eliminate other symptons untill there is nothing else left . Which I believe I have done . Is there any other way to diagnois this ???? And IM very close to going direct to compressor with power and see what happens with gauges hooked up where I can watch whats going on .

 

[DadOSix]

Jump out the low pressure switch. I dont see where this is a computer issue.

If you get decent cooling - low on charge.

I am guessing that the system did not have enough time on the vacuum pump to evacuate and pull out xs moisture.

If no difference, i dunno. These are not rocket science until you get a computer commanded compressor signal like on my sons 16 cruze. What a mess that was!

 

[adamkrz]

I would replace the metering device , Expansion valve before anything else-That controls how much refrigerant enters the evaporator. I would also evacuate what refrigerant you have in the system with a proper vacuum pump to remove any moisture that might have entered the system when using the cans ( moisture enters when the hose is not purged) moisture will freeze at the expansion valve giving many problems, The best way to recharge the system is by weight..

 

[siscofarms]

I would replace the metering device , Expansion valve before anything else-That controls how much refrigerant enters the evaporator. I would also evacuate what refrigerant you have in the system with a proper vacuum pump to remove any moisture that might have entered the system when using the cans ( moisture enters when the hose is not purged) moisture will freeze at the expansion valve giving many problems, The best way to recharge the system is by weight..

06 jeep liberty has the orfice tube instead of expansion valve and I have replaced it along with the drier . I understand this may not be a usual practice but desperation makes you think outside the box . I pulled the lines off the evaperator at the firewall and bowed compressed air thru it . there is no restrictions there . Same on the condensor and seems to be pretty clean also although not as strong as it should have been but with the size of the tubes i do think it was good . I used a torch set up to use dry oxygen to hopefully help with moisture , reassembled , pulled vacuum on it for a couple hours refilled and same thing . I purged everything like you suggested . I really appreciate the comments but as of now , still stumped .

 

[DadOSix]

06 jeep liberty has the orfice tube instead of expansion valve and I have replaced it along with the drier . I understand this may not be a usual practice but desperation makes you think outside the box . I pulled the lines off the evaperator at the firewall and bowed compressed air thru it . there is no restrictions there . Same on the condensor and seems to be pretty clean also although not as strong as it should have been but with the size of the tubes i do think it was good . I used a torch set up to use dry oxygen to hopefully help with moisture , reassembled , pulled vacuum on it for a couple hours refilled and same thing . I purged everything like you suggested . I really appreciate the comments but as of now , still stumped .

Just wondering - when you recharged - 12 ounce cans again? Are you weighing the charge to the specified 26 ounces? Is the oil correct? Takes total 8 ounces of PAG 46 - The wrong oil / excess oil might affect what you are seeing. Those systems are touchy with too much oil. I think the old spec was 2 ounces per component replaced, but can not find that reference at present.

Also - reading where you blew air thru the system - did you do the evap or was it the lines? I am a bit confused on that point.

 

[Turboman280]

Check your fans, that can make the high side spike.

Your low side is not low enough to indicate a restriction.

 

[siscofarms]

Just wondering - when you recharged - 12 ounce cans again? Are you weighing the charge to the specified 26 ounces? Is the oil correct? Takes total 8 ounces of PAG 46 - The wrong oil / excess oil might affect what you are seeing. Those systems are touchy with too much oil. I think the old spec was 2 ounces per component replaced, but can not find that reference at present.

Also - reading where you blew air thru the system - did you do the evap or was it the lines? I am a bit confused on that point.

blew air through the evaparator and condensor . no lines , yet . and yes , 12 ounce cans . the compressor i but on it this spring was pre oiled and was ordered for my specfic model of jeep so i have to assume all is good there .

 

[DadOSix]

So - 12 ounce cans - 2x12=24, your charge should be 26. A little undercharged? Or u got the new can and valves that let a partial can to be used.


So i just visited my 06 kj.

What is the chance that your orifice tube line is installed backward?

What is the chance that an extra orifice tube was installed - say on the opposite side of the evaporator?

Bad Low pressure switch? - I don;t think so. - mine goes below 30 on a low charge system before it cuts off the compressor to protect it.

Bad Hi pressure switch? Maybe. (300 isn’t all that high.)

On a gasser, which I have, the line (oem style) would be dang near impossible to install backward. Recall that the orifice tube is going to behave like a check valve / metering valve. Refrigerant SHOULD only flow 1 way.

If aftermarket hose, like 4 seasons, etc: is flexy enough, i think it possible that it could be installed backward. On mine, cool lines into the evap(from the orifice tube line, cool line into the receiver from the evap, cool line out of the receiver back to the ac compressor. Hot line from compressor to condensor
Warm line from condensor to orifice line. Cool line after the orifice tube heading to the evap.

Basis of refrigeration - compressor takes a cool gas and compresses to a hot - high pressure gas - the condensor brings the gas to a liquid - still hot - the warm liquid sprays thru the orifice or txv and changes into a gas and cools as it travels thru the valve or orifice . The cool liquid sprays into the evaporator and vaporizes, drawing heat from the cabin. Low pressure, gas, warmer that it was on the other side of the evap goes to the receiver to allow oil to fall out and the gas travels back to the compressor to be compressed, and condensed and travel another cycle.

This is all shooting in the dark, bc i still think we need to see complete readings. You are struggling and this system is essentially no different from your strong suit with tractors. If you are not able to do the readings, at least run each hose in the system and check against a known good unit.

Case in point - son is helping with a project truck and putting the intake and exhaust manifolds back on. The bolts have convex washers. He did not realize they all need to face the same direction. I noted when we went to torque and we took em all off to check. 6 of 13 were wrong. All good, but just want to point out i make mistakes too, assuming my helper knows what is in my head.

Let’s fix this beast!

 

[siscofarms]

Here is where we are . I cut the old line apart that had the orfice tube in it , which is sooooo built be a engineer ,ugh, but the old tube had some metal shavings in it . Even though my old compressor still turned free it must have been about to blow up . Soooo , being that there is no way to clean the orfice tube that is in the middle of the line , between bends , , I have another line coming and Im changing the condensor because I wasnt satisfied with the amount of air that was coming thru it when I blew it out . I have since blowed the lines out , which is why I decided to change the line again , not much blow thru either . Basically , the system is completely apart waiting on parts . We shall see

 

[DadOSix]

Here is where we are . I cut the old line apart that had the orfice tube in it , which is sooooo built be a engineer ,ugh, but the old tube had some metal shavings in it . Even though my old compressor still turned free it must have been about to blow up . Soooo , being that there is no way to clean the orfice tube that is in the middle of the line , between bends , , I have another line coming and Im changing the condensor because I wasnt satisfied with the amount of air that was coming thru it when I blew it out . I have since blowed the lines out , which is why I decided to change the line again , not much blow thru either . Basically , the system is completely apart waiting on parts . We shall see

I know it is disappointing to find that , but i think you now have the answer - question - was the shavings on the condensor side of the tube or the evap side? I am thinking condensor - which then totally supports your probllem .. low refrigerant flow and restricted condensor.

Damn fine job in finding the cause!

 

[siscofarms]

yes it was . it actually works as a filter to the evaoarator and dryer . i will update once parts get here .