Car AC Diagnosis of Various Symptoms Dedicated Thread

[afnan.bashir]

Alieeeeeeee!

====

Anyone know where to buy a digital weight scale from? I'm looking for one that measures >20kg?
(Not the hanging type, but the type on which you put stuff to weigh them).

From Lahore you can get it under 2k.

[afnan.bashir]

@xulfiqar @ser_gtr as failing to find any information about in car temp sensor system and its diagnosis. I tried to explore on car. What i observed it it is a pipe going from below the cluster to the blower motor. There is a temperature sensor present infront of the pipe opening below cluster. The main purpose of the pipe is to suck air (i thought it was humidity sensor but its not). Now as blower motor blows air how is it going to suck rite?

Answer is Venturi type system (Small pipe opening inside a big pipe). Blower motor attachment blows the air into the pipe and that causes suction effect. but this effect is just enough to make little air flow for sensor to sense. Amazing

Other than that, I put thermostat to MAX cool at 18 degrees. and attached that sensor to ice. It never triped but on when i adjusted to 19 degrees, it first slowed the fan and then triped the AC. This shows AC System is rite but sensor can still be off specs, I will try and swap it with some other to see if it makes any difference

[Xulfiqar]

After previous top-up of 200g r134a (but I feel I didn't do it till completion since high side coupler kept popping off),
hooked up the gauges today again, filled another 150g freon (was watching the pressures etc all the time).
Also hooked up the new dual thermocouple thermo I bought for DIY keera.
For the first time in eons, I have witnessed condensed water drip out from the AC drain.

The temps are in degC. Ambient today was ~33degC. These readings are at idle (900rpm) not at 1500rpm.

So what does this look like?

On outside air:

On Recirculated (inside) air:

if you got those readings after about 350 grams of refrigerant in your corolla, was your system more than half empty?

on a similar note - I am now facing a dilemma with my camry whose engine I redid, after correcting the AC I am now getting white frost blowing from the center vents and its pretty uncomfortable honestly. Family doesnt like it either (family = mrs) - she adds heating to compensate.

And weather in houston is stupid hot nowadays.

[afnan.bashir]

if you got those readings after about 350 grams of refrigerant in your corolla, was your system more than half empty?

on a similar note - I am now facing a dilemma with my camry whose engine I redid, after correcting the AC I am now getting white frost blowing from the center vents and its pretty uncomfortable honestly. Family doesnt like it either (family = mrs) - she adds heating to compensate.

And weather in houston is stupid hot nowadays.

Wao frost....... You would be like........... Usually i dont work on my AC but when I do, I make sure it frosts. on lighter note i was thinking that if filling the gas by weight he had his system on low pressures i wonder it may be the case with me as i get very low cooling at idle. Also suggest me something about in car temp sensor

[Xulfiqar]

@Xulfiqar @SER_GTR as failing to find any information about in car temp sensor system and its diagnosis. I tried to explore on car. What i observed it it is a pipe going from below the cluster to the blower motor. There is a temperature sensor present infront of the pipe opening below cluster. The main purpose of the pipe is to suck air (i thought it was humidity sensor but its not). Now as blower motor blows air how is it going to suck rite?

Answer is Venturi type system (Small pipe opening inside a big pipe). Blower motor attachment blows the air into the pipe and that causes suction effect. but this effect is just enough to make little air flow for sensor to sense. Amazing

Other than that, I put thermostat to MAX cool at 18 degrees. and attached that sensor to ice. It never triped but on when i adjusted to 19 degrees, it first slowed the fan and then triped the AC. This shows AC System is rite but sensor can still be off specs, I will try and swap it with some other to see if it makes any difference

I wrote of this sensor a few posts back, its the cabin air temperature sensor and in honda build system its plumbed on the suction side of the blower. In some cars there is a dedicated tiny blower motor for this purpose.

This was even present in the old 1992 accords with climate control.

[afnan.bashir]

I wrote of this sensor a few posts back, its the cabin air temperature sensor and in honda build system its plumbed on the suction side of the blower. In some cars there is a dedicated tiny blower motor for this purpose.

This was even present in the old 1992 accords with climate control.

Exactly, I tested it it trips AC when i bring it to near 0 degrees, i never found anything related to resistance test like for evap sensor. should i just change it? i doubt new are available. do you know any resistance check? or i have to swap to check

[Xulfiqar]

its not a simple situation, the unit tests the cabin temperature and then commands what blend door to open/close to "adjust" the air as required.

e.g. lets say you are driving down the road on a 30C day and the ac has been running for a time now, the cabin temperature is near 25C and the set temperature is 24, it will adjust the blend doors to cool down the cab further and then throttle down the blower. The evaporator is still working at max capacity, but as the blend doors are not routing air to it, the system sees "super performance" and the evaporator temperature sensor switches it off.

[afnan.bashir]

its not a simple situation, the unit tests the cabin temperature and then commands what blend door to open/close to "adjust" the air as required.

e.g. lets say you are driving down the road on a 30C day and the ac has been running for a time now, the cabin temperature is near 25C and the set temperature is 24, it will adjust the blend doors to cool down the cab further and then throttle down the blower. The evaporator is still working at max capacity, but as the blend doors are not routing air to it, the system sees "super performance" and the evaporator temperature sensor switches it off.

Well this sounds little hopeless that i cant diagnose it When i attach it to ice first it slows down the blower then further turns off the compressor.

As EVAP Sensor is in specs (tested to manual) and cabin one is working too (not sure if its in specs) what am i left with? at night with car at 1500 and 34 degrees outside wents throw 3 degree c air........ I have not seen AC Cycle even at night. I am think it will damage compressor....

[ahsanonline]

The amount of cooling that was there beforehand, I'm thinking my system was only half-filled, or maybe even less. I didn't top-up by weight, but I made sure to note how much I was putting in there. Kitchen scale zindabad.

[Xulfiqar]

Well this sounds little hopeless that i cant diagnose it When i attach it to ice first it slows down the blower then further turns off the compressor.

As EVAP Sensor is in specs (tested to manual) and cabin one is working too (not sure if its in specs) what am i left with? at night with car at 1500 and 34 degrees outside wents throw 3 degree c air........ I have not seen AC Cycle even at night. I am think it will damage compressor....

you dipping the thermistor in ice is showing the CCU that the cabin has gone to freezing temperature somehow (maybe you are driving with windows down on the north pole perhaps)

It will reduce the blower speed to minimum and shut off the AC too.

[afnan.bashir]

you dipping the thermistor in ice is showing the CCU that the cabin has gone to freezing temperature somehow (maybe you are driving with windows down on the north pole perhaps)

It will reduce the blower speed to minimum and shut off the AC too.

lolx yes okies so what should i move next to? is there any diagnosis of non triping symptom. I think if both sensors are fine then may be its not cooling in normal range?

[afnan.bashir]

The amount of cooling that was there beforehand, I'm thinking my system was only half-filled, or maybe even less. I didn't top-up by weight, but I made sure to note how much I was putting in there. Kitchen scale zindabad.

I used my digital scale..... but your experiment has placed my procedure in question

[searchingeyez]

@xulfiqar @afnan.bashir my car ac is now working without tripping but on motorway when sun is directed in front to windscreen, ac was not removing heat and not making the car comfortable even at the speed of 120 .... do u have any knowledge regarding this?

[ahsanonline]

I used my digital scale..... but your experiment has placed my procedure in question

Its not a nice feeling to be second-guessing oneself, is it? Itni mehnat karnay k baad one suddenly fears that maybe the system still isn't performing well...

Tripping of AC is not to be taken as a benchmark. Of course with Lahori heatwave I wouldn't expect it to cool down to a level that would bring evaporator to near freezing temp or inside cabin temps low enough for that other sensor to do that job indirectly. If you can, post manifold readings, line temperatures and conditions when they're taken so we can do a proper comparison.

One thing I've noticed is critical: When everything else is almost the same, its the airflow across the condenser (fast fans) that enables proper cooling; with fans at half speed the system has just too much heat in itself to do any noticeable cooling. And then also if the weather outside is like in the 42+degC then I think it would be injustice to expect it to perform as it would in 33degC ambient.

I'm thinking to put the clear anti-UV film on all windows from the outside (except front windscreen). IMO even if it lasts just one season then its worth it. I'm also considering reinforcing roof insulation.

[afnan.bashir]

Its not a nice feeling to be second-guessing oneself, is it? Itni mehnat karnay k baad one suddenly fears that maybe the system still isn't performing well...

Tripping of AC is not to be taken as a benchmark. Of course with Lahori heatwave I wouldn't expect it to cool down to a level that would bring evaporator to near freezing temp or inside cabin temps low enough for that other sensor to do that job indirectly. If you can, post manifold readings, line temperatures and conditions when they're taken so we can do a proper comparison.

One thing I've noticed is critical: When everything else is almost the same, its the airflow across the condenser (fast fans) that enables proper cooling; with fans at half speed the system has just too much heat in itself to do any noticeable cooling. And then also if the weather outside is like in the 42+degC then I think it would be injustice to expect it to perform as it would in 33degC ambient.

I'm thinking to put the clear anti-UV film on all windows from the outside (except front windscreen). IMO even if it lasts just one season then its worth it. I'm also considering reinforcing roof insulation.

What line temperature is needed? low pressure line?

[afnan.bashir]

@Xulfiqar @afnan.bashir my car ac is now working without tripping but on motorway when sun is directed in front to windscreen, ac was not removing heat and not making the car comfortable even at the speed of 120 .... do u have any knowledge regarding this?

this can be many things. For that you need to hoop up manifold gauges and see what readings you get

[syncview]

Its not a nice feeling to be second-guessing oneself, is it? [emoji14] Itni mehnat karnay k baad one suddenly fears that maybe the system still isn't performing well...

Tripping of AC is not to be taken as a benchmark. Of course with Lahori heatwave I wouldn't expect it to cool down to a level that would bring evaporator to near freezing temp or inside cabin temps low enough for that other sensor to do that job indirectly. If you can, post manifold readings, line temperatures and conditions when they're taken so we can do a proper comparison.

One thing I've noticed is critical: When everything else is almost the same, its the airflow across the condenser (fast fans) that enables proper cooling; with fans at half speed the system has just too much heat in itself to do any noticeable cooling. And then also if the weather outside is like in the 42+degC then I think it would be injustice to expect it to perform as it would in 33degC ambient.

I'm thinking to put the clear anti-UV film on all windows from the outside (except front windscreen). IMO even if it lasts just one season then its worth it. I'm also considering reinforcing roof insulation.

from where did you get those clamp k type thermocouplers and for how much?

Its not a nice feeling to be second-guessing oneself, is it? [emoji14] Itni mehnat karnay k baad one suddenly fears that maybe the system still isn't performing well...

Tripping of AC is not to be taken as a benchmark. Of course with Lahori heatwave I wouldn't expect it to cool down to a level that would bring evaporator to near freezing temp or inside cabin temps low enough for that other sensor to do that job indirectly. If you can, post manifold readings, line temperatures and conditions when they're taken so we can do a proper comparison.

One thing I've noticed is critical: When everything else is almost the same, its the airflow across the condenser (fast fans) that enables proper cooling; with fans at half speed the system has just too much heat in itself to do any noticeable cooling. And then also if the weather outside is like in the 42+degC then I think it would be injustice to expect it to perform as it would in 33degC ambient.

I'm thinking to put the clear anti-UV film on all windows from the outside (except front windscreen). IMO even if it lasts just one season then its worth it. I'm also considering reinforcing roof insulation.

[wasim625]

What line temperature is needed? low pressure line?

Both lines. With thermocoupler.

[wasim625]

from where did you get those clamp k type thermocouplers and for how much?

Aliexpress.com for RS.1800

[syncview]

Aliexpress.com for RS.1800

great! is it a clamp type?