Resolved AC system pressure

[miliman13]

Problem, when i drive Hwy speeds my vent temp rises, instead of dropping.




Low side : 60PSI
High side: 180PSI
Vent Temp: 50F
Ambient Temp: 90F
Conditions: Idle, Shaded area.






Based on this information what can you tell me?


Not enough freon ?
To much?
Evap?
Valve? Ect??
Note, i accidentally let out a tiny bit of R and one change was the vent temp rose to 55F

Thank you

 

[Coppermitsu]

How you getting these stats a professional a.c. high n low side gauge set? First guess your about out of refrigerant, I hope your not putting garbage like the parts store recharge kits in it with the stop leak. If you are I switch guess to you have clogged components....also can try washing out the fins on your a.c. condenser strongest cleaner you can find and a hose spray straight in so you don't bend the fins.

 

[miliman13]

How you getting these stats a professional a.c. high n low side gauge set? First guess your about out of refrigerant, I hope your not putting garbage like the parts store recharge kits in it with the stop leak. If you are I switch guess to you have clogged components....also can try washing out the fins on your a.c. condenser strongest cleaner you can find and a hose spray straight in so you don't bend the fins.

Thanks for the response and vote of confidence.

Last time AC was touched was a few yrs ago.
Full vac, and filled with the green big cylinder of 134 from an ICE company.

Since then no leaks or touching.

Yeah gauges are legit was gifted them by a fellow Eng student and active HVAC pro.
condenser fins are good, it received a good service recently .

SIDE NOT MASSIVE SPAL 1900CFM FAN on deck with a Shitty Mishi as well.

ive read conflicting info......
That my low side is way too high..
That i have to much R, and also not enought.

 

[Coppermitsu]

Sorry and good during the right stuff n seem pretty mechanicly inclined, I'd say if your low side is actually to high just because it's a simple check push the Schrader valve in for a Mili sec just to see if anything comes out I've seen those fail on semis usually but it throws the gauges off, what's on those again I forget as far as metering device goes a office tube or accumulator either way I'd bet it's clogged or faulty?... to much refrigerant shouldn't hurt anything it woulda broke stuff going in I'd think, are you sure the compressor is engaging ?

 

[miliman13]

Sorry and good during the right stuff n seem pretty mechanicly inclined, I'd say if your low side is actually to high just because it's a simple check push the Schrader valve in for a Mili sec just to see if anything comes out I've seen those fail on semis usually but it throws the gauges off, what's on those again I forget as far as metering device goes a office tube or accumulator either way I'd bet it's clogged or faulty?... to much refrigerant shouldn't hurt anything it woulda broke stuff going in I'd think, are you sure the compressor is engaging ?

I'll be honest... I kind of struggled to understand what you just wrote .
I mean it respectfully .

Yes the compressor is on..... how else is the vent temp 50f?

 

[Coppermitsu]

Sorry haha super tired and being lazy on my phone, how cold do you want it to get? What's spec supposed to be for vent temp? And okay so your compressor def is engaging that was a dumb question on my part you should have a accumulator on that if I remember correctly from deleting mine, the canister with the 2 hard lines running in and out of it. Check and see what the 2 lines do there, typically one will get moist or even a frost coating and the other should be warmer but still cool to the touch.

 

[miliman13]

Idk specs.
Grams , or pressure, ect..
But compared to my daily or should be 40f at idle and 35f at hwy speeds not 70f

 

[Lou98GSX]

The high side pressure is high it should be around 35 to 40 but your vent temp is not that bad but it could be better if the pressures are where they should be . I would start by getting all the freon out and evacuate the system for at least 10 minuets and recharge with the right amount and recheck your pressure . If there is still a problem then you could have a sticking orifice in the suction line . The orifice is also called an expansion valve . that valve i believe is mounted on the inlet of the evaporator .

 

[miliman13]

Vvv

The high side pressure is high it should be around 35 to 40 but your vent temp is not that bad but it could be better if the pressures are where they should be . I would start by getting all the freon out and evacuate the system for at least 10 minuets and recharge with the right amount and recheck your pressure . If there is still a problem then you could have a sticking orifice in the suction line . The orifice is also called an expansion valve . that valve i believe is mounted on the inlet of the evaporator .

You mean the low side.
30psi High would mean a dead compressor....

Also, what is the right amount???
There is zero info on this subject in all the manuals, threads,ect.........

Only a stock dsm would have this info in the bay..

 

[Puller]

Does the compressor cycle on and off or run non-stop? You pressures are too low for 90* ambient temp. What do the pressures go to at 2k-3k rpms? If a 2G guy could chime in, I am almost sure the refrigerant capacity is 26oz.

 

[miliman13]

Does the compressor cycle on and off or run non-stop? You pressures are too low for 90* ambient temp. What do the pressures go to at 2k-3k rpms? If a 2G guy could chime in, I am almost sure the refrigerant capacity is 26oz.

Which pressures bud??
Only the high side is a bit low.. As I've mentioned already..

High side slightly goes up , at 2-3k.
Low stays the same.

Compressor is constant...
If it wasn't pressure would be low on low..

 

[Puller]

Your low is too high and high is a bit low bud. Step one is you need to get it evacuated so you can know if you're over or under on refrigerant.

 

[mechanized]

Jmo but I've always gone by weight so long as pressures done get crazy out of whack...evac, then give a new charge to what it calls for...I think someone mentioned 26oz.?

Your low is too high and high is a bit low bud. Step one is you need to get it evacuated so you can know if you're over or under on refrigerant.

 

[Brembo]

Ideally and we don't live in ideal world the low side should be somewhere around 30psi. The high side usually is doable the outside temp so somewhere around 200psi. I say charge it and make sure the fans work correctly. Make sure blend door works and is on cold. Drive it and see if it improves with extra air flow. If all fails then you need to take it apart and change few things. While you have it apart check to see if anything is clogged. Then change orafice tube/expansion valve and accumulator. Charge it again and check the results. That's the steps I would take. A/C sometimes get complicated but in your case I think it's just low. A lot of time with a/c problems you will find low or too much frion, compressor not working, fans not coming on, today I have a jeep that the blend door motor on left side sometimes goes hot even though you set it on cold, something is cloged which is rare but it does happen. I had a motor home with clogged low side line and it drove everyone banana, changed many things until we blow in the line to find it clogged. Good luck it's your findings. By the way my 1g has a/c functional and I love it.

 

[1990TSIAWDTALON]

Ditto on the pressures.
Low 30 (or higher if it is hot out, I have seen 45 on a HOT day.)
High 200-250 (or higher if it is hot out, I have seen 300 on a HOT day.)
I always evacuate my stuff now. You can buy a pneumatic vacuum pump that hooks to your air compressor and, by venture effect, will draw a very good vacuum on your system. I can get 26-30Hg on most of my stuff. Refill with 2 cans of R134, which is 24 oz. See how it feels. Should be nice and frosty! If you think you NEED that extra 2oz of refrigerant, then crack another can but my Chevy takes 28oz and is working fine on 24oz until I have to charge someone else's system and have a bit left over.

This is what I use to evacuate A/C systems, looks cheap, is cheap, works great though. I usually leave it on between 15-30 mins depending how many components I have replaced. Like I said it pulls a strong vacuum on the system 26-30Hg.

http://www.ebay.com/itm/Pneumatic-4...415765?hash=item41af175395:g:8jkAAOSwdzVXk4TI

You must be logged in to view this image or video.

 

[miliman13]

You pressures are too low

Pressure = singular
Pressures = plural

Ideally and we don't live in ideal world the low side should be somewhere around 30psi. The high side usually is doable the outside temp so somewhere around 200psi.

Thank you for your input.

Ditto on the pressures.
Low 30 (or higher if it is hot out, I have seen 45 on a HOT day.)
High 200-250 (or higher if it is hot out, I have seen 300 on a HOT day.)
I always evacuate my stuff now. You can buy a pneumatic vacuum pump that hooks to your air compressor and, by venture effect, will draw a very good vacuum on your system. I can get 26-30Hg on most of my stuff. Refill with 2 cans of R134, which is 24 oz. See how it feels. Should be nice and frosty! If you think you NEED that extra 2oz of refrigerant, then crack another can but my Chevy takes 28oz and is working fine on 24oz until I have to charge someone else's system and have a bit left over.

This is what I use to evacuate A/C systems, looks cheap, is cheap, works great though. I usually leave it on between 15-30 mins depending how many components I have replaced. Like I said it pulls a strong vacuum on the system 26-30Hg.

http://www.ebay.com/itm/Pneumatic-4...415765?hash=item41af175395:g:8jkAAOSwdzVXk4TI

You must be logged in to view this image or video.

I'm glad you mentioned that tool .
I've seen it in a YT video but didn't know much else..

Thanks to you all.....
" who contributed "....

Still if anyone else has ideas do tell..

I plan on adding a bit to see,
Since i removed a bit.

Waiting on my **3RD** P- valve.
So can't drive her just yet

 

[1990TSIAWDTALON]

Still dealing with that Brembo caliper or have you narrowed it down to the proportioning valve now???

 

[Lou98GSX]

Sorry i meant the low side was high

 

[miliman13]

Still dealing with that Brembo caliper or have you narrowed it down to the proportioning valve now???

Yeah man.. The first two collapsed internally... So no flow to the rear..

Waiting on another one... Hopefully this one will finally work...




Just for fun..i have an update.

With engine off the low and high are 95psi..
Today low was 10-20 High 150-160
Vent temp 55F ( i think this is because i released some freon)

I added freon
Dropped to 50F
Low went to 30 High 180..

Seems good right??

Added more freon,
Temp lowered to 47F
But**** low fluctuated from 30-60
High was almost the same maybe 200.

When it fluctuated the temp also fluctuated.

So i believe the compressor we kicking on and off..

Perhaps i added to much.

I'll know more, when ever i drive her and maybe release some more freon from the system..

 

[asexton6969]

What do your vent temps increase to while cruising on the highway?

While I agree your low pressure side is a tad high, your idling vent temps are phenomenal. A general rule of thumb is 20 degrees below ambient temps is acceptable. I personally dislike looking at pressures and making decisions on that alone. I typically will notate what they are while(if) the a/c compressor is engaged. I will do an EVAC and weigh what is removed against specification. Vacuum test, look for UV dye leaks (if system is filled with dye) 1 oz recharge PAG oil and refill system. Monitor vent temps and check pressures.

1998 Mitsubishi Eclipse GSX - R134A Capacity: 1.54 - 1.63 lbs.

Seeing your last post, it really sounds like your just guessing at this point. Not to mention releasing freon to the atmosphere which is illegal.....

 

[miliman13]

What do your vent temps increase to while cruising on the highway?

While I agree your low pressure side is a tad high, your idling vent temps are phenomenal. A general rule of thumb is 20 degrees below ambient temps is acceptable. I personally dislike looking at pressures and making decisions on that alone. I typically will notate what they are while(if) the a/c compressor is engaged. I will do an EVAC and weigh what is removed against specification. Vacuum test, look for UV dye leaks (if system is filled with dye) 1 oz recharge PAG oil and refill system. Monitor vent temps and check pressures.

1998 Mitsubishi Eclipse GSX - R134A Capacity: 1.54 - 1.63 lbs.

Seeing your last post, it really sounds like your just guessing at this point. Not to mention releasing freon to the atmosphere which is illegal.....

Releasing into a empty cylinder ..
No one said atmosphere.

Cruise temps when last recorded were 70F.

What am i guessing ?

 

[asexton6969]

Thank you, I did mistakenly think you were releasing to the atmosphere. Are you actually weighing what you are putting in the system? Do you believe you could setup your gauges to see whats happening while driving? Not sure if your set is long enough to make that work. I would assume initially you were low and now that you have added some after your first post you may have even added too much. Did you happen to notice if the passenger side vents seemed to be a different temp from the drivers side?

 

[miliman13]

^ i can't secure my thermometer to the sides.

I will try to record while driving as well.

Perhaps i added a bit more.


I'll find out all of this when ever im back on the road..

 

[Puller]

Pressure = singular
Pressures = plural"

Cool.

Just go get it professionally evac'd and recharged instead of randomly adding and subtracting freon and then trying to guess if you have a charge or component issue. Just pay the 100 bucks to have someone with a real machine evac, leak test and recharge it to spec. Then you'll have a baseline to start dissecting and analyzing pressure and component issues.

 

[1990TSIAWDTALON]

Watch your compressor. Is it kicking on and off as the pressure rises? If so the high pressure switch is kicking it off so it doesn't get hurt (meaning it may be a bit high). I'd drive it and if it doesn't work out or the high pressure seems to be kicking it off, put some back in that empty cylinder and see if it quits, or pay the shop a good chunk of your wallet.... If we all work on our DSM's, this should be something we do to, with the proper tools, just like the rest of the things on our cars. I am glad at least one of mine still has A/C!