What are the pressures our cars (1991 Honda Accord) need for high and low. I know some cars are different. Low as a rule of thumb from the research I have done said 35-40psi and high is related to temperature. Is this correct?

Im doing it tomorrow and it is supposed to be 55F so would high pressure be about 160psi is that correct? And low 35-40psi?

 

here is what looks like a fairly accurate chart

http://www.ackits.com/aacf/ptchart.cfm

 

hi today I pulled a vacuum, and it did not drop crazily maybe from 28 to 26 in 15 minutes, so I decided to go ahead and add a couple cans I added 3 of r134a and a shot of dye. The compressor would cycle on and off every 10 seconds to start, but then it would last over a minute before it cycled off, then it didn't cycle at all, but when I set it to recirculation it cycled every 10 seconds again. it was 60 outside and the vent temp was at 38F steady. I looked around the front seal of the compressor and every leak point I could see, but found nothing, but then I looked at the whole compressor and found that the back of the compressor and there I found a leak. What would cause a leak in the back of the compressor? The front seal also had something bubbling from it. Should I just go by a compressor from my junkyard, they have one with an A grade and they have 90 day warranty's.

Did the compressor cycle because of the weather? Is there a pressure switch inside the compressor not just in the line near the compressor and the leak is making the compressor think it doesn't have enough pressure?

 

Curtie -

I am not able to help any but I just wanted to let you know that I have been following your posts on this subject as I am getting ready to undertake going through my whole A/C system like you have done.

I do have a question, if you were uncertain of your system being able to hold fluid without leaking why did you use 3 cans to test your system?

That is like $45, right?

My mechanic friend whose advice I consider pretty good told me if I buy one can he has the dye and he would be able to see if my system was airtight or not.

Just wondering your reason, not being harsh on you.

 

How many ounces of R134a did you add?

Is the leak coming from the body of the compressor? If you look carefully, the compressor body is three pieces of metal sealed with large o-rings. The three sections are held together by long bolts.

It sounds like the o-rings and/or the shaft seal are leaking. This could be due to putting too much R134a in the system, so that is why I asked the first question.

 

We typically pulled vacuum to 29 inches and then it had to maintain for at least 30 minutes. Junkyard parts in an a/c system is a crap shoot at best...just my opinion.

 

well I had gift cards for walmart so I got the r134a for nothing. After one can the compressor didn't run long enough to look for the leak. After the second I still couldn't see any leaks and therefore I though maybe I didn't have a leak. So I added the third can and then I found the leak. If I knew I had a leak like that I wouldn't of added 3 cans. I still have 3 cans left anyway.

The system holds 34oz of r12 so it is something like 29oz of r134a. you don't actually get all of the refrigerant from each can so I added the correct amount. My pressures were actually low. My High side was 120 and low was 22.


Yes it was coming from the body of the compressor How would I fix the seals on the compressor?

 

You would have to take apart the compressor. It isn't really hard to do, but reassembly can be a pain. Especially when the pistons inside the compressor fall out. You will want to replace the shaft seal as well, since you will be removing it.

You should consider a junkyard compressor. Carefuly inspect around the shaft seal for signs of leaking (oil buildup).

 

Alright so I think I'll go take a look at the junkyard compressors soon. Hey maybe i'll get lucky and find a new compressor from a car that died after they changed it. I might also be interested in buying a junkyard compressor if it is good, then rebuild my compressor.

What causes the compressor to cycle, is it normal to cycle?

I also have a weird issue, when I turn the ac on or the compressor cycles the rpms jump to like 2000rpms, What causes that? Is the compressor pulling alot of power or is there somekind of switch that will raise the rpms when the compressor turns on? I have cleaned all of the idle adjusters IACV, FITV and TB.

 

Charge by weight when system is empty, starting at 80% of R12 capacity and increasing slowly watching high and low side pressures. You should wait until air temps are at least 70F to charge.

I would not try to repair your compressor if a body seal is leaking. I tried that once and got a 2nd leak in same seam for my troubles.

Try to find a good used compressor. You should be able to find one for < $100.

Compressor cycles when the evaporator temperature sensed by the the thermostat goes to slightly below freezing, perhaps 30F. Compressor cycles off to prevent freezing of evaporator.

ECU compensates for compressor load to try to maintain a rpm level. If engine is cold, that may be fairly high, but should decline to about 700-800 rpm when engine is fully warmed. If not somethings wrong.

good luck