L2ILL

Just to be sure the low side port on 92 is on the left hand side or passenger side parallely with the radiator correct? It looks like the bigger pipe which would mean the Hi Pressure side I think...is why I ask.

I am replaceing the AC compressor....and need to know how much to fill it?

Im going to pick up 2 full size cans...you guys think that should cover it?

I've got a full manifold in my shed so id like to set it to the correct readings as per the gauges.

tollboothwilley

Low side is always the smaller connection

i believe the system requires 18-19 oz so 2 cans should be sufficient

If you are replacing the compressor make sure you add PAG oil as well. i'm not sure how much PAG oil is required for the system.

L2ILL

Thanks the compressor came pre-oiled.

Does anyone know where the readings should mark? when u hook up the manifold gauges?

This is the most important info.

justinsbg

R134A pressures are as follows:
Low side- at idle and ambient temp between 70-90 degrees, good pressure wil be between 25-35psi.
High side-same conditions, good pressure will be between 175-185.
Those readings are based on years of experience. Hope that helps.

L2ILL

Thats perfect....thank you.

Do you happen to be able to confirm the low side..is the tube on the passenger side...in front of the radiator?

Reason I ask is the size of that one when I follow it seems to get bigger. Altho I need to look closer I guess. But a much larger higher pressure pipeline does not seem to contrast sharply from the other line. looks possible the difference is little.

phootbag

The high-side line is smaller and heads toward the condensor after leaving the compressor. The low-side line is larger and runs from the firewall to the compressor.

justinsbg

One important thing to note about the above pressures I gave: those aren't static pressure readings, those are with the system running. If you're asking which fitting is which, I believe on that car the High Side port is near the firewall on the passenger side. The Low Side port I think is at the front near the condensor or close to the compressor.

tollboothwilley

Justin - my wife has a good friend who works on Hondas all the time. He told me that in the 100* range(ambient temp) that the H pressure side should be around 250 or so during idle. He said they havea machine that normally measures the amount r134a that they put into the system but that 250 range is normal for the high side. your thoughts?

justinsbg

I work on Honda cars 9-11 hours a day, 5 days a week (thats's all I work on) and I'm just telling you based on my experience. Granted I live in the South East and summertime temps usually are around the mid to lower 90's, the pressures aren't going to fluctuate that much. Also aknowledging I work in an air conditioned shop and temps on hot days are usually around 75 inside, again I don't believe the pressures are going to fluctuate that much. I think even at an ambient temp of 100 a high side pressure of 250 is too high. At idle I wouldn't want to see it above 200. Just to validate my statement, since it's expected to be a scorcher on Tuesday I will check a vehicle's pressures outside. I'm almost certain that I'm acurate with the pressures I gave. Those are my thoughts.

phootbag

It should be understood that the A/C systems are designed to be charged with a certain amount of refrigerant measured in weight.

While the system will operate within a predictable range of pressures, pressures should really only be used to diagnose malfunctions within the system. Always start with a known proper charge.

DCFIVER

Your AC sytem is gonna suck (Poor cooling) and fail. Sorry you are not properly evacuating or refiling the system. And despite the fact the the compressor has oil, you still need to measure it.

DCFIVER

185 psi on a 90 degree day? Not on a properly operating AC system. You need more experience....

DCFIVER

This correct.

DCFIVER

Ah my friend you are very wrong. Heres some good learning for you....
https://honda-tech.com/forums/tech-misc-15/%2A%2A%2Aair-conditioning-c-guide-how-works-when-doesnt%2A%2A%2A-2900177/

justinsbg

So you're telling me that the hundreds of happy summertime customers that I've sent down the road with 39 degree air temperatures out of the vents have disfunctional a/c systems? I don't think so. There are book statistics (which you posted in your write up), and there is real life statistics. I'm sure if you're a technician you understand that those book statistics and numbers are a genral theory of operation. If I fixed cars everyday solely based on readings given by what a book told me I would be in serious trouble, and so would technicians all over the world. Book information is great for a good general understanding of how a system is supposed to work, but experience in this field is the best teacher. The numbers that I gave are numbers that I deal with on a daily basis....gained from experience. On an aging car and system, numbers aren't going to be what the engineers stated in the manual they wrote when the car was new. Good technicians understand that more than book statistics have to be considered. There are many more variables that have to be considered when diagnosing a vehicle. Good technicians understand the utilization of common sense and practical application of book knowledge. Common sense and experience has to come into play when your working on cars with age, mileage and wear.

justinsbg

Also understand that if there is a proper charge in weight in the system the pressures will directly reflect that as long as the compressor is functioning properly. In this case the proper charge in weight is 800-850grams (28-30 ounces). If the system does not have the proper weight in charge, the pressures will reflect that. Hope you understand.

DCFIVER

Im telling you that if you see 185psi on the high side on a 90 degree day and you consider it normal, you need some education in the fundamentals of AC operation. The numbers you gave are wrong. Just because they are what you"deal" with does not make them anymore right. So either you have been doing your customers a disservice with faulty AC work or you have been using faulty AC gauges for "years" and you have erroneous readings.

You are inexperienced, it is quite obviuous. You can continue to argue to try to save face or you can learn. Age and milage have ZERO effect on AC readings. A properly working AC system will have the same readings on a 20 year old vehicle(assuming R134) as it does on a brand new vehicle.

I did not write that thread I linked you to, another master tech did. I linked you to it because it is correct.

justinsbg

I'm most definitely not trying to save face, there's no need. Like I said, your post of that chart is merely a GENRAL description of hvac systems, and is meant to be used as a good base understanding of pressure/temperature relationship. There is most definitely more variables to consider. Compressor's wear just like engines. Some compressors produce better pressures than others. You are absolutely correct when you say "a PROPERLY working system will have the same readings 20 years later". How many 20 year old systems do you know that are as good as they were when they were new? Probably not too many. I don't know what kinds of vehicles (if any) you work on on a regular basis, but it's probably not Honda. I take a tremendous amount of pride in my work, and that is why I am employed by one of the best Honda Specialty shops on the East Coast. The customer cars we service are satisfied. You're "wise" comments are not needed. I'm trying to help this gentleman by giving him data that I see every day. Data that helps me bring back customers to the shop by fixing their cars right the first time. I appreciate your thoughts, as wrong as they are. Also, I work in an air conditioned shop and don't check vehicles outside. Tomorrow I will check pressures outside on a good working system and post a video of my findings. It's supposed to be around 95 so it will be a great opportunity. Have a good 4th of July.

phootbag

What's your point? That I'm right? You don't charge by pressure. You charge by weight. You diagnose by pressures.

Ok, I'll throw you a bone. You CAN charge by pressure but will not have results that are as consistent as when charging by weight. Better?

justinsbg

You two guys are quite the argumenative bunch. I'm not saying anyone is right or wrong. I'm simply stating facts, so that other guys who read this thread have a better understanding of pressure, temperature, and weight relationships. When I'm re-charging a system I look at the weight of what I've put in as well as the pressure gauges. By doing that, if for some reason your scales are't calibrated correctly you shouldn't have any problems with over/underfilling. Pressures are a great indicator of how a system is performing. If the job gets done right and the customer is satisfied that's all that matters.

DCFIVER

Im a CMAT/L1 with 15 years experience son. The first 6 years of my career were spent on Honda and Acura vehicles. I graduated from the Honda PACT program. That is where I received my original automoitve training. Including air conditioning classes. Ive done hundreds of AC repairs vehicles over the years, including Hondas and Acuras I OWN 2 Acura vehicles now that I regularly maintain and i just recharged my RSX a few weeks ago. I know exactly what I am telling you and you are wrong. Period. Whats more, AC systems follow the same rules across the board, regardless of make or model of the vehicle. Be it a Honda ,Toyota, or GM. The pressure/temperature relationship is gonna be the same (or very similar) The only variable that you have introduced is working in an air conditioned building. That is not the norm and is not how AC performance is properly measured. People dont drive their cars in air conditioned buildings.



Do your check outside and record it. You may be surprised at what you find.At 95 dergrees your highside PSI will be in the 220-250 range.

justinsbg

For all the skeptics, here is a link to a video proving everything that I've said. It's still about 86-87 degrees where I am in North Carolina. High Side pressures never rose more than 190 psi, Low side pressures never rose more than 35 psi. A High side pressure of 250 or more is too much! No more arguing, I'll let the facts speak for themselves. I don't care if it's 86-96 degrees, the pressures will not fluctuate as much as 30 or 50psi. It seems you might have a little to learn yet my friend. A properly working A/C system does not need 220-250 high side psi. All I work on is Honda/Acura and I know my stuff. Who is the inexperienced one now??
http://www.flickr.com/photos/3143471...7627000128431/
Copy and paste it in you URL if you can't click on it here.

phootbag

Hey, sorry if I jumped your ****. I just read back and can't understand why I decided you claimed that you can charge a vehicle by pressures alone and that would be sufficient. You never said that.

Seems like we're on the same page as far as that is concerned. Sorry.

justinsbg

No worries man, it's all good.

justinsbg

Doesn't matter if I check it inside or outside if I know what the pressures are supposed to be. The pressures are supposed to be as I already stated.....see video. Answe this question for me: if a system is cooling at optimum performance at a high side pressure of 185 and a low side pressure of 35 why would you want to add more and raise the pressure? Doesn't make sense to have pressures as high as you say. If you have any questions about anything don't hessitate to ask.