When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I figured out why my a/c has never worked. This lil rascal comes off the low pressure side, but today I discovered it isn't actually attached to anything! Where does it go?
POV in the photo is from the passenger's side wheel well, with swaybar and radiator in the background.
That's not in the refrigerant path.
You can see both low and high side hoses behind it.
Where does the other end of it hook too?
It might be an evaporator drain hose but that doesn't match up with my cars (all 3 are NBs).
The clamp shown is for low pressure applications (below 30 psi).
Just doubled checked it, you are correct, it actually comes directly out of the bottom of the evap canister.
BTW, you still want that VVT head technicalninja?
Yep, bring it up in the Mazda next time you're up north and I'll diag the puppy for free...
Quick self diag:
Do you have more than 50 psi showing in system?
If not, the high-pressure switch is also a low-pressure safety switch and nothing will happen. You have to be above 50 for the system to work.
Does the face of the compressor turn nicely, not tight, does not have sticky spots or feel like a pepper grinder?
If so, great.
SO, you have pressure and the compressor passed the "scratch and sniff" test, crank it up and switch the system to max cold, max fan speed, face vents. and recirc.
Both the compressor and the fans should be working. If your internal blower motor does not work fix it first.
If fans on and compressor not: check for power at connection to compressor clutch. Single wire will show hot and a two wire connection will be hot on one and ground on the other. The hot leg should only be hot with car running and compressor commanded.
No power to compressor: diag AC clutch wiring. Often the ac clutch relay is the same part as the horn relay, I'll swap them anyways, The clutch relay has been cycled a couple of million times and the horn relay less than 100....
If you have power and ground getting to compressor and the clutch doesn't activate you have a bad clutch coil. Easiest to replace compressor. CALL me for your source.
Pretty much everything offered on Internet, box auto parts stores is stuff I have LEARNED not to install.
I have nearly a 100% failure rate on aftermarket compressors.
On older vehicles these cheap assed compressors are all that is available now.
It's getting damn hard to get real Calsonics (Mazda OEM) for the early cars.
Compressor on and fans not: diag fan issue. You can test the refrigerant system without the fans but you need a big assed shop fan against the nose of the car to make up for them.
You can use a fanless system but ONLY above 30 MPH. You MUST turn the compressor OFF at every stop sign, ect...
The fans keep the system from having a heart attack when stopped. All the radiator shrouding gets even more important when you add another heat source between the intercooler and the radiator. Fans get more critical as well'
No fans will make the engine overheat in 5 minutes.
No fans will make the ac system overheat in 30 seconds. If you're lucky the high-pressure switch saves your ****, if not you either blow the relief valve or something else dies (usually it cracks the compressor body).
I've never seen a relief valve that re-sealed after a venting situation. The relief valves usually come with a compressor and are no longer available separately (they used to be!)
Compressor on, fans on, inner blower working (air flow through vents) = systems up and now it's time to start looking at the gauges.
You get to here and then you should call me. It's so much faster to do this type of thing over the phone...
Later
Rick
With all this drift bois installing radiators in the trunk, I don't understand why people in Texas or Florida or other Hell-ish states don't do remote mount condensers.
+1 for the 100% failure rate on aftermarket compressors, along with axles, driveshafts, alternators, starters....used OE 4 lyfe.
Anyways, came in here to say that plastic fitting clips into the subframe, to look like it goes somewhere, but surprise! Its just VTA.
With all this drift bois installing radiators in the trunk, I don't understand why people in Texas or Florida or other Hell-ish states don't do remote mount condensers.
It's the airflow potential. A NA Miata probably has 2 square feet of airflow through the nose. A NB has more.
At 60 MPH you have the potential for over 10,000 CFM through that hole. 10K CFM is a massive amount of air.
Normal high side pressure, down here in Hell at 105 degrees, will be between 180 and 240 at 2000 rpm static in the shop with the big assed fan on it (I run that almost always).
At 60 MPH that same car at the same RPM will show 90-120 on the high side. Lots of newer cars have AC high side pressure as a data field in the PCM data and you can see the changes on a scan tool.
Very few also report low side pressures but when they do makes it makes me happy.
60 MPH halves the system running pressure and it the ONLY reason the compressors last as long as they do...
As long as you can supply that type of airflow mounting the condenser elsewhere is perfectly fine in my book.
You can also add another condenser past the first one to further cool the refrigerant.
Whether it helps or not is completely dependent on how well engineered the original system is.
Well-engineered system, it will not do ****, just add complexity.
Poorly engineered system often kicks *** with a secondary condenser.
I'm not happy unless I'm hitting compressor cycle point (lowest the electronics will allow) at 30 MPH blower at half speed at any normal ambient temp. I've seen 110 degrees this year.
On most of the Japanese based vehicles this is below 40 degree at the vent.
I guess my bigger point was the rear radiator guys move it there to maintain airflow to the radiator (should be with fans and ducts and such, but that's another thread) when mounting a giant intercooler up front. With temps rising around the country, the condenser's airflow is more and more important.
We've already had 16 days over 90 here in Portland, that's enough to make me consider putting AC in my own car. I've already got the button... pretty much already there.
We hit 90 in March!
It looks like 40+ days over 100 this year to date.
We will not drop below 90 till sometime in October.
My HOT season last till Halloween
I would really, really like to visit you Curly
Can you put me up for 8 weeks?
90 degree days sounds like Heaven.
But I'd miss out on 30% of my yearly earnings if I visited...
Right now I'm working 7 days a week, 12+ hours per day. This will last another 10-12 weeks.
I'm planning on closing Thanksgiving week and not re-opening till after New Year.
I'll get some Miata work done then...
I figured out why my a/c has never worked. This lil rascal comes off the low pressure side, but today I discovered it isn't actually attached to anything! Where does it go?
POV in the photo is from the passenger's side wheel well, with swaybar and radiator in the background.
As you figured out, it is the "pure" air from the evap canister, and it's stock location is in a hole in the subframe, just to confuse everyone...
08-07-2022, 03:52 PM
Where does this connection go to?
0
