phideauxiii

Hi all! I'm Ryan. I've just posted over in the "greetings" forum, and added the car in question to the "garage" and other minor profile tweaks, and am ready, i believe, to ask my question(s).

My mother drives a 2006 CR-V SE (UK made, VIN SHSRD78916Uxxxxxx)
She bought it used, one year old, from Criswell Honda, a quite nice dealership in Germantown, MD.

Since then, it's had one HVAC related issue (condenser), although it was within, and covered by, the extended warranty. Now that said warranty has reached its expiry, when "problems arise" they get looked at with a whole new pair of eyes (mine)

Today, in the morning (82 F Ambient, 60%+ RH) we were driving, and the A/C was functioning as I expect it to, and as it typically does. We've been running the A/C for approximately a month so far this season without issue. It typically cools quite quickly, and on "MAX A/C" it's like a meat locker in there within minutes...

On the return journey, the A/C ceased outputting cold air. I made sure the A/C light was on, and that there were no "check engine" or other warning lights on the dash. It went from sweet, sweet cooling and dehumidification to "that sweat box in Cool Hand Luke" in approximately six seconds flat, and I WISH that was hyperbole, but that's how I recollect it.

I didn't hear any unusual noises at the time (or at all, for that mater) and for the two minutes that I had my hand over the vent after "the realization", I could feel the air *TRYING* to get cooler (on recirc), but not doing so. I shut down the compressor at the switch, and redirected to the Harbor Freight for a set of manifold pressure gauges, a multimeter (mine is elsewhere) and some nitrile gloves. I then went to Pep Boys to procure 24oz. (a bit much, but only sold in 12oz increments) of refrigerant (DuPont Suva R134a), and a pierce-tapper/shorthose with Quick Connect to recharge into the low side.
I have already a decent thermometer to place in a vent.

***RESULTS OF PRELIMINARY TESTING***


Upon returning, I assembled my new three hose/two dial manifold pressure tester/charge unit, and brought it out. The vehicle had cooled a bit since arriving but the ambient temperature was still at least 90 degrees fahrenheit, and the humidity was killer.

Made sure all valves were closed and NPT's tight, I connected the HS/LS quick-connects to their respective ports, and started the vehicle. I ran it five minutes at 2,000RPM to bring it to operating temperature, and the engine fans had begun spinning. When up to temperature, I activated the air conditioning, MAX A/C, I dropped to idle, went about to the engine bay, and opened the valves on the back of the HS/LS quick connects, which instantly caused a reaction in the dials on the meter. They rose quickly, and showed a reading that did not waver over the four minutes of testing, and also caused a realllllllllllllllly ichy feeling to develop in the pit of my stomach:

LOW SIDE : 125 psi
HIGH SIDE: 125 psi

They are equal, and too high for the low side, too low for the high side.

I am praying it's not a compressor, and perhaps a pressure switch had freaked out or something, and halted the compressor mid-stroke.

My questions are:

1) What's it typically mean when the HS/LS pressures match in the context described?

2) What are some common-sense electrical checks I can make? I've pulled the two A/C relays i could find (in the engine bay) and tested them by applying 12VDC to the proper terminals and, after the "click" of the solenoid firing, heard the "beep" from my multimeter indicating that there was continuity between the appropriate points on both relays *that i could locate*. All fuses look okay so far, I've looked under dash on driver's side and in engine compartment.

3) is there a way to find out if the compressor is kicking in? I had my mom activate the A/C while i was near the compressor, but heard no audible "snap" of a clutch closing. Is the 2006 CR-V SE equipped with a clutchless compressor?

4) True, compressor is mounted on the bottom of the motor, although, there is a generous amount of plastic shielding covering that area, and the unit looks okay to a *cursory* visual inspection.

5) What are SPECS for this HVAC system? I've been able to ascertain that:
it holds between 17.0 ounces and 18.9 ounces of R134a, and takes a PAG oil charge (but i don't know the viscosity required for the PAG, and had figured most of it would still be in the system). I honestly don't think it's leaking at all, given the pressure in the system, and it's consistency...


Any advice would be most appreciated. I am a fast study, and hope to learn a bit, and perhaps save my mom a bit of loot, as she is quite ill, and has been hit with bill after bill for the HOME a/c in the last month, and now the CAR a/c is on the fritz!

Again, *most* projects are within my technical ability, aside from those that need structural welding, or RECOVERY of refrigerant. (I have no idea that R134a escaped, Saint Peter!)

Thanks so much for reading all that, and especially considering i'm the FNG.

Sincerest Regards,

Ryan.

phideauxiii

*UPDATE*

I've let the car settle/cool for about two hours. The H/L pressures BEFORE (engine hot/ac running) was 125/125 PSI. After the cooldown, with the vehicle off, i re-opened the valves for another pressure check. They're both still equal, but down to 105/105 PSI.

Is this indicative of a leak, or is it normal for the pressure do drop very gradually in a charged system?

No matter what, the values remain the same, and I don't *THINK* the compressor is engaging. Perhaps I could... force it to engage, temporarily? (like thirty seconds) and see if the HS/LS develop an offset?

Thanks!

Ryan

phideauxiii

And another update, as the situation progresses... by observation (not easy on the 2nd gen CR-V) I CAN tell that the compressor clutch is not engaging. I've checked the relays and pulled the harness off the only switch/thermistor I could find, on the high side, jumped it, it kicks on the fans and raised the idle, but no compressor. I've tried jumping the relay points to engage it... nothing, voltage checks out ok to the terminal block...

Starting to get a bit frustrated...

Any ideas? Thank you very much for reading!

Ryan

phideauxiii

All the googling I've done has left me less enlightened than I was when I began this diagnosis. I've learned it's a scroll-type compressor, which is prone to catastrophic failure rather than good, old-fashioned "regular" failure. Like, "throwing a rod through the block wall" kind of failure... thankfully, this hasn't happened. Does anyone have a schematic of the HVAC, specifically wiring and tubing? That'd be extraordinary.

Nothing I've found via searching today has matched the issue I'm experiencing. Many results tell me that when the high and low sides are equal, that the compressor is shot, but there's plenty (130 PSI) of pressure in the system - the dial gauge I'm using is simply telling me that the pressure is equal on both sides, so really the low side is way high, and the high side's a bit low... although the readings are equal. No differential I can see.

Any ideas at all? Thank you!

Ryan

dogbiscuit

you're super concerned on the PSI's of the system. do they cycle when you run the ac? Low side pressure should cycle in and out.

PSI probably isn't where you should be looking. if it's not cycling when your system is running then your compressor is surely not working. you should watch the low gauge while its running and it should be cycling from low pressure to high at each compressor kick. exact pressures don't matter as things like the charge/air/water/ambient temperature. affect the pressures.

if the compressor isn't working check/fuses/relays/etc also a low charge in the system will cause the compressor to not kick on.

you may want to spend the ~$100 and have a shop recover/charge the system to spec first. worst case scenario you're out ~$100 however you honestly don't know what's in your system right now and that's why I suggest this. have them throw dye in with the recharge as well which most shops will do anyways and this will help you in blacklight/leak testing.

Don't use those autoparts store recharge kits they only get you in trouble if your system isn't properly vacuumed.

phideauxiii

Thanks for your reply.

When the a/c goes out, my first inclination is to check pressures. Out come the gauges lol...

It's built pressure, as I'd said it was working, and quit. Now there's 125 PSI on BOTH sides, and the compressor isn't engaging. I was looking for a method to jump the clutch circuit to engage the compressor manually for a few seconds and see if the dials move.

Where's the A/C clutch wiring? Can I activate compressor clutch from relay box or is it elsewhere?

Also, possibly unrelated, but we'd just had the oil changed the day before it died, any ideas?

Thanks!
Ryan
:-)

phideauxiii

By the by, I do have a manifold gauge kit and a vacuum pump, so sucking it out down to -30 or so isn't an issue....if I HAVE to :-)

phideauxiii

o well.