Diagnosis and Advice for 2002 Honda Civic

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Diagnosis and Advice for 2002 Honda Civic

Postby MichaelJ » Tue Jun 07, 2016 4:25 pm

Hello all,

I've lurked on and off here for a while but this is my first official posting. I'm working on my wife's Civic, which is displaying intermittent cooling (sometimes moderately cool air, sometimes hot air.) It makes for fun husband/wife interactions: "AC isn't working." "I just checked it, it's blowing cold." …and so on.

Can a failing/intermittent clutch connection effect condenser fans?
The number one thing I've discovered is that the compressor isn't engaging with regularity. It is intermittent. I'm not sure if it's entirely clutch related as the condenser fans are associated. I witnessed the fans twitch and try to start (curb testing with AC on MAX at idle). The clutch/compressor had not be running. Suddenly the fans came on at full and when I looked down, the compressor was spinning. This only lasted a few seconds, though. All the while AC on MAX.

Electrical Tests
I continuity tested all related fuses, and all passed. I swapped relays around in the box with the horn relay. Each time I would test the horn to see if it worked properly. Not the most scientific method, but all relays did operate the horn. I pulled the harness for the switch connected to the Accumulator, jumpered the harness with no effect - bad clutch? It was after these tests that I noticed the fans twitch, then come on full, only to stop again a few seconds later.

System Pressures
I have checked system pressure with a Low/High gauge set a couple of times. All pressures given will be LOW/HIGH and given in PSI, AC set to MAX, air set to recirculate cabin air.

My first check was when the system hadn't been engaging/cooling for few days to a week. It read both static (engine off) and with engine running but compressor not engaged - 120psi/150psi, no difference in reading what-so-ever. This is a very high low-side and a low high-side, indication according to my research - bad compressor?

I rechecked after the intermittent cooling symptom occurred. I hooked up the gauges with the car off and engine dead cold. I can't remember the exact static pressure but there were equal Low/High pressure readings. The compressor and condenser fans came on when I started the car. Low pressure readings started at 25psi but worked up to 30psi after a few minutes of running. High pressure stayed pretty constant between 150-155, which is still kinda low for an 80°F day (shouldn't it be at around 200psi or so?)

It is my guess that at the very least I have an ailing clutch, but the compressor may also be suspect. The price to swap a complete compressor/clutch is about the same as only a new clutch, so a full compressor/clutch swap is the course I'm looking to take unless someone here can offer guidance to the contrary.

While I'm in there, is there anything else I should look at? Please advise.
Is now the time to replace the Accumulator? Expansion valve? New O-rings all around? New Low/High port valves? These things are pretty cheap to replace, should they be done? Anything else to do?


Your collective advice is most appreciated. I am thankful for the wealth of information and knowledge collected here. Maybe soon I'll put cool air back into my El Camino (it came to me stripped out.) Cheers!
michael j

1970 Chevelle SS396 - "Elektra" - Hotter than Hell and never going to have AC!
1980 El Camino
2002 Honda Civic LX
2006 Kia Sportage

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Re: Diagnosis and Advice for 2002 Honda Civic

Postby Tom Greenleaf » Tue Jun 07, 2016 5:59 pm

Hi and welcome!

Yes a fan clutch could have a larger gap than it could pull in especially at first when already used and warmed up. May be hard to get to but try to measure air gap. About all like .020 or so will work OK up to .025 or some more. It's getting power (if you check and do) just coil can't make enough magnetic force to pull in -- trivia -- magnetic forces are less with heat - don't but you can't pick up a glowing nail with a magnet or shouldn't be able to.

Pressures have one more thing for high side is at what RPM did you read those? At about 1,500 or a little more should peak out at about 2.5 X the incoming air temp in F. thru grilled with fans blowing but in front of the grille. Saying 80F can be totally wrong if over cold ground or hot pavement or whatever it's the air coming in the system knows.

If clutch will stay off when it really should be on you can CAREFULLY tap on the still outer plate with all caution as it may snap right on so use something that wont harm it or shoot out and hurt you or anything. I don't think there's room for a rubber hammer maybe a rubber hose or wood?

Relay swapping saves a lot of time and proves one works. NOTHING hack about that to me! It's faster than you could try to test one out for sure.

Rule that out.

So if high pressure can't do the 2.5X temp thing but compressor CAN work ok the most common thing is just low charge. Some of these call for so little total a couple oz off (low not high - avoid that!) will begin erratic behavior and higher vent temps.

The best way is first look for leaks while pressure is in it. Then if able to accurately recover what's in it, if possible know what came out and put back exact listed charge on sticker under hood. If it doesn't all behave just ducky even for the day that's good info and a leak to find the next job or see how long proper charge lasts. I say that because if it hasn't been touched since 2002 a little loss isn't going to be easy to find and could go years? That time if it returns matters on how easy it will be to find the leak(s.)

Don't hurry to replace anything quite yet. It may be OK and new may not!

Get some more info I think this will be fairly easy,

T
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Re: Diagnosis and Advice for 2002 Honda Civic

Postby MichaelJ » Fri Jun 10, 2016 4:09 pm

Tom!

Thanks for the reply, and I apologize for not answering sooner. I wanted to get more information collected before replying, but the lag is starting to appear rude so this will be a quick reply.

I have dug up a Honda Factory Service Manual and wiring diagram for this Civic. There are some good diagnostic stuff in there, which I will run through. Did you know this Civic has a self-running diagnostic feature which will give alerts, kinda like the ECM, on a range of functions like: air mix control and motor circuits, evap temp sensor open/short, linkages/doors etc? Pretty cool.

I have a bunch of home work to do and will get back to everyone with some hard data. In the meantime, here is the work underway. To gain access to the compressor, while working in my driveway on jack stands, I've removed the driver's front wheel and unbuttoned the plastic inner fender panels.

ImageImageImage

More soon!
michael j

1970 Chevelle SS396 - "Elektra" - Hotter than Hell and never going to have AC!
1980 El Camino
2002 Honda Civic LX
2006 Kia Sportage

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1985 Honda VF700F Interceptor
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Re: Diagnosis and Advice for 2002 Honda Civic

Postby MichaelJ » Fri Jun 10, 2016 10:01 pm

Tom Greenleaf wrote:Hi and welcome!


Thanks!

Tom Greenleaf wrote:Yes a fan clutch could have a larger gap than it could pull in especially at first when already used and warmed up. May be hard to get to but try to measure air gap. About all like .020 or so will work OK up to .025 or some more.


I found a PDF online of the Honda Service Manual for this car. Great diagnostic information there, including wiring diagrams, connector pin-outs, etc. The Official Spec™ for clutch gap is .020" ± .006". When the engine is dead cold my gap is a loose .022" and a tight .023… so call it .0225", well with in spec.

Tom Greenleaf wrote:If clutch will stay off when it really should be on you can CAREFULLY tap on the still outer plate with all caution as it may snap right on so use something that wont harm it or shoot out and hurt you or anything.


This was the first thing I tried after I pulled back all the inner/underside tupperware so that I could see the compressor/clutch. No effect. See what happens with the electrical tests later!

Tom Greenleaf wrote:It's getting power (if you check and do) just coil can't make enough magnetic force to pull in


IT has been a big bear of a knuckle scraper to test for 12v leading into the clutch field coil as it is secured and so very buried behind large metal objects like the alternator. And thanks again to the Service Manual for showing me that there is a Compressor Thermal Protector switch inline between the 12v source and the field relay. Basically, if the switch senses an overheating compressor it kills the power to the clutch field coil to prevent any further damage to the system. The CTP switch connects to the main harness via a large plastic connector plug, but there is also a bullet connector after the CTP switch which connects to the field coil. Both the connector plug and the bullet connector are impossible to reach with bare hands, but with the help of an extremely long set of needle nose pliers and alligator clip test leads for the multimeter, I was able to get some readings:

Voltage Tests
I confirmed 12v at the engine harness side of the AC Clutch pigtail. Good.
I could NOT read voltage at the bullet connector on the other side of the CTP switch leading to the coil. Bad.
This leads me to believe that the Compressor Thermal Protector Switch is bad and stuck in the open state when it should be closed. This prevents the AC Clutch Field Coil from ever seeing power to operate. I believe I was seeing the effects of its death in gradual degrees.

Other electrical test suggested by the Factory Service Manual
Field Coil resistance - 3.05 ~ 3.35 Ω @ 68°F Bad. I measured 3.7 Ω which is on the high side and out of spec. Taken on a dead cold engine in the shade @ about 76°F ambient.

The Environmental Control Self Diagnostic - performed at the controls within the cabin. No errors displayed, so all of the environmental controls/linkages/doors/fans/etc are working correctly (according to the system, but I didn't suspect them anyway.)

Tom Greenleaf wrote:Pressures have one more thing for high side is at what RPM did you read those? At about 1,500 or a little more should peak out at about 2.5 X the incoming air temp in F. thru grilled with fans blowing but in front of the grille. Saying 80F can be totally wrong if over cold ground or hot pavement or whatever it's the air coming in the system knows.


Idle, about 1000rpm. I was technically working in full sun, however it was morning and the sun was rising over the trunk, so the pavement under the condenser was still cool due to the car's shadow.



Sooooooo...
I think I found the culprit, the Compressor Thermal Protector switch. I think I also found a Field Coil with higher than spec resistance. Less current flowing at the same voltage = less magnetic pull… Yes? No?

My future looks like I will need to replace the CTP switch and clutch/coil at the very least, which means I'll have to remove the compressor to do so. I've not priced this out yet, but what do you all think of a new compressor assembly (not remanufactured) if the price is comparable or lower than the two parts separately?

In my mind my next steps seem to be to evacuate and measure the amount of refrigerant in the system, good info to know for further diagnosing. I do not see any leaks with a Mark I Eyeball but I would also replace shraeder valves and caps for he High/Low ports as well as O-rings for the compressor's hose connectors. I

Interesting Fact
The Honda Service Manual states that the pressure switch operates in the range between 28 psi and 455 psi. Below or above those numbers and the system is cut off to preserve the compressor.


That's all of my further investigation evidence. Ideas? Comments? Cautions? Thanks!
michael j

1970 Chevelle SS396 - "Elektra" - Hotter than Hell and never going to have AC!
1980 El Camino
2002 Honda Civic LX
2006 Kia Sportage

Motorcycles
1984 Honda VF1100C
1985 Honda VF700F Interceptor
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Re: Diagnosis and Advice for 2002 Honda Civic

Postby MichaelJ » Mon Jun 13, 2016 2:15 pm

Hi. I've posted two followups to this thread on Friday and nothing has appeared yet. Does a moderator need to approve something? I've tried to be very in-depth so that we can have the best possible discussion… and there is no way I can remember everything I said.
michael j

1970 Chevelle SS396 - "Elektra" - Hotter than Hell and never going to have AC!
1980 El Camino
2002 Honda Civic LX
2006 Kia Sportage

Motorcycles
1984 Honda VF1100C
1985 Honda VF700F Interceptor
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Re: Diagnosis and Advice for 2002 Honda Civic

Postby MichaelJ » Thu Jun 16, 2016 12:00 pm

I replied to this thread a couple of times with my further investigation, but nothing has appeared here. I thought I was simply waiting for admin approval, but it's been close to a week of waiting. Have I done something to piss of the forum?
michael j

1970 Chevelle SS396 - "Elektra" - Hotter than Hell and never going to have AC!
1980 El Camino
2002 Honda Civic LX
2006 Kia Sportage

Motorcycles
1984 Honda VF1100C
1985 Honda VF700F Interceptor
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Re: Diagnosis and Advice for 2002 Honda Civic

Postby Tom Greenleaf » Tue Jun 21, 2016 5:01 pm

Problems with site joy stick. You should be all set to go but for some reason out of order till I post this then let's get back to it,

Tom
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Re: Diagnosis and Advice for 2002 Honda Civic

Postby cornbinder89 » Tue Jun 21, 2016 6:07 pm

I wouldn't worry about the clutch resistance, its in the ball park, but a bit high. Lots of things could explain that. Most things have to be way out of spec to cause a problem. Concentrate on the open limit switch.
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Re: Diagnosis and Advice for 2002 Honda Civic

Postby Tom Greenleaf » Tue Jun 21, 2016 7:29 pm

Sorry again not much time, site is currently under spam attack to clear out while reading and typing this is nuts!

Clutch gap - almost any. Spec about .020. The coil creates a magnetic force to engage it - the hub then spins at the speed of the belt. It too large it can't pull that far which happens to some as large as .030 is problem territory but that can vary by vehicle how over they can handle. If electrically thought fine and clutch is good otherwise just a love tap when it should be engaged on outer hub it will snap to - great clue it's too big a gap without digging any more that would be next.

Tools required up to taking compressors out on some. IDK - In your pic it looks like I could adjust that one in place?

I'll be back or another may come by. Just no time to fully read this thread thru for you right now with more thoughts or suggestions from me,

Tom
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Re: Diagnosis and Advice for 2002 Honda Civic

Postby MichaelJ » Sat Jul 02, 2016 10:58 pm

It gives me great pleasure to announce that I have successfully repaired my Honda Civic's A/C problem!!!! And I did so without ever having to crack the sealed system open.

As I have stated previously, I found that my Compressor Thermal Protector (CTP) switch was stuck in an open state, which prevented the compressor clutch field coil from ever seen voltage, and therefore never engaging. It is the ONE glaringly obvious fault in the system that I can detect. By Occam's Razor, this would be both my easiest and best bet at a cure. I found a genuine Honda replacement part on http://hondapartscheap.com for under $59.00 (down from the list price of $84.00). If you're working on Hondas this site will save you some major $$$. Highly recommended.

I will spare you the details of GETTING ACCESS to the compressor. I will simply say that I had to dislodge the power steering pump and reservoir (not opening that system, it can be pushed out of the way) and removing the alternator. Suffice to say that it was a cramped and knuckle-brutal task to get in there. I like Honda's style of belt tensioners used here on the PS pump and alternator, though the use of wing-nut heads instead of a hex-head bolt was a fail.

Here is what the compressor looks like with PS pump and alternator out of the way:
Image

The device with two red wires entering it is the CTP switch. It was an M'Fer to remove! I ended up grinding out the black plastic insulated interior with a Dremel on low-speed, using a snake extension. I went very slowly to only remove the soft plastic interior of the old CTP switch.

ImageImageImage

Once the plastic interior was removed I could then use a pick to remove the copper outer housing of the CTP switch. It is glued into the body of the compressor with silicone sealant. There is not much to it, but MAN is it a bear to clean out and remove!!!!

ImageImage

Next I cleaned the CTP switch cavity in the compressor with the Dremel and a grinding stone bit. The Dremel speed was on the slowest possible setting. I only wanted to clean out old silicone sealant and dirt.

ImageImage

Time for Reassembly!

This is the new Honda CTP switch to be installed:
ImageImage

This marks the point in the job when the ratchets are switched from "lefty-loosey" to "righty-tighty". It's a very pleasing moment to say the least! Again, I will not bore you all with the process of reassembly, with the exception of two things. First: whenever I dig into a system that probably hasn't been touched since the factory, I ALWAYS clean all rust scale off my bolts and nuts, clean the threads, and reassemble with anti-seize compound as a just-in-case I ever have to do anything in this area again. It takes only a moment, and it also aids in the reassembly process. Second: the AC/Alternator and Power Steering belts are both over 14 years old and have 95k miles on them. They looked okay from the top, but they showed severe dry rot and cracking on the underside. They are cheap to replace, and since I'm in there anyway it is smart to do so now.

Image

I reassembled the AC Compressor and Alternator first, then started the engine to test. System voltage at the battery was over 14v so the charging system is happy, and when I went into the cab to test the AC I was greeted by nice COLD air. AAAAAAAhhhhhhhhhhh!

I had purchased a new O-ring set, a new dryer, and new valve stems and caps, just in case I needed to evacuate and open the system. I didn't actually need them, though I did use the new valve caps to replace the old ones. Compared to the cost saved by NOT replacing the compressor (a bill of around $230 for a new Denso unit), the few dollars wasted on unused o-rings/dryer is negligible.

I will also state that when testing my system pressures, I'm still showing around 30-35/160psi. These readings were done on a cool day (around 79°F) with low humidity and in an area that had been shaded from the sun all day. That still seems like a low high-side pressure to me, but I'll take it for now.

Thank you all for being a sounding board and listening to me think out loud. I mostly want to thank Tom G, for being the voice of reason and making me pause from running out and buying a new compressor. Also, thank you to cornbinder89 for his reality check. I appreciate all of this site's collected knowledge and hard work!
michael j

1970 Chevelle SS396 - "Elektra" - Hotter than Hell and never going to have AC!
1980 El Camino
2002 Honda Civic LX
2006 Kia Sportage

Motorcycles
1984 Honda VF1100C
1985 Honda VF700F Interceptor
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Re: Diagnosis and Advice for 2002 Honda Civic

Postby Tom Greenleaf » Sat Jul 02, 2016 11:21 pm

Thanks for the follow up for the fix and nice pics to show it is great for archives.

Some (shouldn't) will just jump that (double shouldn't) so it has continuity again usually even newer in very hot conditions they were said to trip too much. Never here on me anyway.

Good work,

Tom
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Re: Diagnosis and Advice for 2002 Honda Civic

Postby MichaelJ » Sun Jul 03, 2016 1:04 am

I LOVE that Honda designed the compressor with a safety feature in the Compressor Thermal Protector switch. The thought of jumpering it to a voltage source would technically work, but it would also be the cause of great/expensive damage down the road. For the price and effort, I have no problems keeping the system with its stock protections.
michael j

1970 Chevelle SS396 - "Elektra" - Hotter than Hell and never going to have AC!
1980 El Camino
2002 Honda Civic LX
2006 Kia Sportage

Motorcycles
1984 Honda VF1100C
1985 Honda VF700F Interceptor
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Thank You, ACSource!

Postby MichaelJ » Sun Jul 03, 2016 1:22 am

A major thank you is in order for the owners and moderators of this site. You guys are always here, answering questions and helping out. It's like you're living your work on your free time at home. Let me please take a moment to acknowledge that and to thank you for all you do here. The Internet may not have made our society better in the inter-personal skills and manners categories, but it has done smashingly well connecting the special interests of people who know with the people who need/want to know.

I will make no illusions here. I am a tourist. I have a strong set of mechanical abilities, but I'm a lightweight concerning the specifics of THIS topic. I cannot tell you how much I appreciate that there are places like this that openly welcome my questions and ramblings, and wind up providing solid advice for me to complete a task the right way. Thank you, fellow posters, admins, and site owners. Your work has not gone unnoticed here.
michael j

1970 Chevelle SS396 - "Elektra" - Hotter than Hell and never going to have AC!
1980 El Camino
2002 Honda Civic LX
2006 Kia Sportage

Motorcycles
1984 Honda VF1100C
1985 Honda VF700F Interceptor
MichaelJ
 
Posts: 9
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Re: Diagnosis and Advice for 2002 Honda Civic

Postby cornbinder89 » Sun Jul 03, 2016 3:19 am

160 high side equals 115 deg condensing temp which is about right. The closer you can get the condenser temp to ambient the better it will cool.
You don't want high pressures, they are a necessary evil as the temp rises. The more heat you remove at the condenser, the lower the high side will be. 30 deg above ambient temp isn't bad.
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Re: Diagnosis and Advice for 2002 Honda Civic

Postby Tom Greenleaf » Sun Jul 03, 2016 5:48 am

Thanks again and for compliments - credits to sir 'cornbinder89' - sometimes all I do is dig out the spammers here.

This and or other cars do that to shut down hot compressors = hot gas right there but can be fooled by engine heat. The high pressure cut out switch also cuts out system and many cut out if engine too hot as well. Plenty of failsafes items most too late to really save a compressor. You hope one works but are doing without A/C while failed if failed fully like that.

Can't know every model's ideas and car makers don't make compressors usually just set specs for what will fit. All too tight underhood these cars no exception.

For this type sorry it burnt rather than reset itself as temp exchange is OK as cornbinder said. Do make sure fan(s) work properly and many use a higher speed when pressure higher or none at all if vehicle speed is adequate to do all the work and save fan use at all dependent on assorted factors may or may not get passive air at speed of vehicle, weather and winds or even the vehicle in front of you even at highway speeds as in behind a large box trailer.

Air dam under bumpers help at speed especially.

About site FYI: This all volunteers sharing experiences and know how. Free to users also attracts the spammers, hackers. You shouldn't see that junk on a family friendly site.

Good luck with a long lasting fix,

T
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UPDATE - One month on...

Postby MichaelJ » Tue Aug 02, 2016 3:56 pm

Well, it's been a month, so here's an update to the job. The Little Civic is still blowing ICE COLD. It's the best A/C we have, and that's good because it has been HOT here. More than 12 straight days of +90° with high humidity.
michael j

1970 Chevelle SS396 - "Elektra" - Hotter than Hell and never going to have AC!
1980 El Camino
2002 Honda Civic LX
2006 Kia Sportage

Motorcycles
1984 Honda VF1100C
1985 Honda VF700F Interceptor
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Re: Diagnosis and Advice for 2002 Honda Civic

Postby Tom Greenleaf » Tue Aug 02, 2016 4:10 pm

Appreciate the follow up and that's it's working to your expectations,

Tom
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