technine

In my 98 civic ex (stock nothing modified at all) the AC will cut off and on while driving at any moment. It will be blowing cold for a while and all of a sudden it will just not be cold anymore.

I also noticed that the AC fan would come on and stop while I was looking under the hood and it sounded like the compressor kicked off as well and then they both came back on while I was inspecting under the hood a few times.

I thought it was moisture in the system so I had the system evacuated and I refilled it myself and also checked vacuum before for any possilble leaks. All checked ok. So I filled it with R134a to the appropriate pressure and it ran fine for the first day, but it wasn't really that hot of a day so I didn't use it too much.

Today was a little warmer so I used it and maybe about 10 min or so of it on it stopped getting cold. I'm thinking it is either the AC pressure switch or the AC thermostat in the evaporator. Anyone have any idea what it could be?

Mr.EM1_EK

my geuss would be the switch, or either you have a short somewhere and it's grounding out. check your connections to be sure first.

technine

I'll check all the connections and see if I missed something or if something doesn't look right. Everything seems to be ok from what I seen under the hood, but I'll check again.

So you think it could be pressure switch?

Mr.EM1_EK

yeah thats where i would start

y7turbo

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by technine &raquo;</TD></TR><TR><TD CLASS="quote">

So you think it could be pressure switch? </TD></TR></TABLE>

what are the pressures when it cuts out?

technine

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by y7turbo &raquo;</TD></TR><TR><TD CLASS="quote">

what are the pressures when it cuts out? </TD></TR></TABLE>

When I have it set to the ac on max (if I remember correctly) it will be at around 25psi to 30psi and when the ac fan cuts off it goes back up to 40psi give or take 5 or 10 psi. Whenever the ac fan comes back on it will go back down to 25 or 30psi. I am measuring it with an AC gauge I bought at autozone where it is color coded to tell you where the safe pressure settings are and where the dangerous or low pressure settings are if that means anything.

IE IL IP IH

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by technine &raquo;</TD></TR><TR><TD CLASS="quote">I'll check all the connections and see if I missed something or if something doesn't look right. Everything seems to be ok from what I seen under the hood, but I'll check again.

So you think it could be pressure switch? </TD></TR></TABLE>


just check all of the connections, all grounding locations and whatnot. should be good after that... maybe bump for some more help...?

abusedhusband

iTrader: (1)

i had the same problem with my 97 ex four door. i did the same thing you did and didnt fix it. so them i changed the expansion valve. SAME THING. so i broke down and bought a compressor and BINGO, never did it again.

technine

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by abusedhusband &raquo;</TD></TR><TR><TD CLASS="quote">i had the same problem with my 97 ex four door. i did the same thing you did and didnt fix it. so them i changed the expansion valve. SAME THING. so i broke down and bought a compressor and BINGO, never did it again. </TD></TR></TABLE>

So your fan would turn off too? Isn't there a pressure switch in the compressor itself? I seen it in the service manual and I think it's like a $55 part at kragen. If it was the compressor, wouldn't the fan still be on?

abusedhusband

iTrader: (1)

it depends. my problem was the reeds in the comp were doing whatever they were doing to let the high and low side open up to each other and cause the system to equalize and the pressure switch would shut if off for safety. same thing happens when a expansion valve goes bad. but this case it wasnt it. so thats why my fans cut off to.

Mr.EM1_EK

the switch is in the receiver. it is number 19.



i was also going to say your compressor. i dont think there is a switch on it though.

technine

I think it's part #6 which should be thermo protection switch.

technine

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by abusedhusband &raquo;</TD></TR><TR><TD CLASS="quote">it depends. my problem was the reeds in the comp were doing whatever they were doing to let the high and low side open up to each other and cause the system to equalize and the pressure switch would shut if off for safety. same thing happens when a expansion valve goes bad. but this case it wasnt it. so thats why my fans cut off to.</TD></TR></TABLE>

That would make sense. I'll go to pick and pull and see if I can get a cheap compressor. Do you know if a compressor off any civic/crx will work as long as it's a D series motor? There are a lot of older EF's there and I would have a lot to choose from.

y7turbo

i don't think what he said makes sense for you problem. if the valves were bad, the head pressure would be low and the suction pressure would be higher than what you have.

the freeze stat on the evap coil shuts the compressor off at around 36 degrees. when your pressures are at 25psi your well below the 36 degrees. the saturation temperature in the evap coil is in the mid 20's at the pressure.

are you sure you have the correct charge in there? it almost seems that its undercharged, or a restriction in the system. without taking more measurement's, its only a guess. but hell what do i know, i only service systems up to 200 tons.

i personally would add some gas to get the suction pressure back up and go from there.

i would do a few more tests before you go buy a new compressor and maybe throw out a good one. if you don't have the correct tools to do it then do whatever you want. be a parts changer, its your money not mine.

technine

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by y7turbo &raquo;</TD></TR><TR><TD CLASS="quote">i don't think what he said makes sense for you problem. if the valves were bad, the head pressure would be low and the suction pressure would be higher than what you have.

the freeze stat on the evap coil shuts the compressor off at around 36 degrees. when your pressures are at 25psi your well below the 36 degrees. the saturation temperature in the evap coil is in the mid 20's at the pressure.

are you sure you have the correct charge in there? it almost seems that its undercharged, or a restriction in the system. without taking more measurement's, its only a guess. but hell what do i know, i only service systems up to 200 tons.

i personally would add some gas to get the suction pressure back up and go from there.

i would do a few more tests before you go buy a new compressor and maybe throw out a good one. if you don't have the correct tools to do it then do whatever you want. be a parts changer, its your money not mine. </TD></TR></TABLE>

Sounds good. According to my gauge I have a little more to go before it is too much pressure. I'll add some more and check back and tell you if it's fixed the prob.

technine

I added a can more and I had slightly more pressure, but same thing happens: turn it on and it will cut on and then off and then on and then off and if you drive long enough it will just stop working all together.

What could it be? Pressure switch? Thermo protect switch in the compressor? Compressor? Expansion valve? I'm stumped.

y7turbo

with only knowing the suction pressure everything is just a guess. you have done what you can on your end, since you dont have all the correct tools to diagnose an a/c system. now its time to take it to a pro.

abusedhusband

iTrader: (1)

just change the compressor. if it dont work, wrap it up nicely and return it. just tell them it was wrong.

y7turbo

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by abusedhusband &raquo;</TD></TR><TR><TD CLASS="quote">just change the compressor. if it dont work, wrap it up nicely and return it. just tell them it was wrong.</TD></TR></TABLE>

With "want some troubleshooting done, pm me" in your signature line, how can you say such a thing? Is that how YOU troubleshoot, by part swapping?

That's such a hack/bullshit way of doing things.

Troubleshoot with common sense and proper tools. If none are available, take it to someone who has BOTH

abusedhusband

iTrader: (1)

a/c is one thing i dont troubleshot. i can use what little knowledge i have for it and help, so if you dont like my suggestions, dont read them. and how is it butch to try something to see if it works. i can see if i said take a part that does not fit and make it fit.

abusedhusband

iTrader: (1)

WONDERING IF YOU EVER FIXED YOUR A/C. IF SO WHAT FIXED IT.

technine

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by abusedhusband &raquo;</TD></TR><TR><TD CLASS="quote">WONDERING IF YOU EVER FIXED YOUR A/C. IF SO WHAT FIXED IT.</TD></TR></TABLE>

I haven't done anything to the car yet after filling it. I'm gonna get a compressor from pick n pull, but I don't have anytime lately, but as soon as I make some progress I'll let you all know. Sorry for no update yet.

technine

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by y7turbo &raquo;</TD></TR><TR><TD CLASS="quote">with only knowing the suction pressure everything is just a guess. you have done what you can on your end, since you dont have all the correct tools to diagnose an a/c system. now its time to take it to a pro.

</TD></TR></TABLE>

I have a a/c manifold gauge kit and a a/c vacuum. The vac pressure looked good and didn't change after 30min without vacuum pump on so no leaks. What else can I test?

technine

update:

I checked the pressure reading on the Low side and High side and low side was higher than high side. What does this mean? Shouldn't the high side always be at a higher pressure? I'm thinking of replacing the compressor.

y7turbo

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by technine &raquo;</TD></TR><TR><TD CLASS="quote">update:

I'm thinking of replacing the compressor.</TD></TR></TABLE>

its your money.

dont forget, replace the drier any time the system is open.