AC Stops Cooling After Moving in Stop and Go

Joined
Dec 21, 2009
Messages
775
Location
WPB, FL
Ive been having an odd issue with my G37s HVAC. It blows cold, pressures are correct (High and low sides), cooling fan turns on when it should...etc

But lets say, for example, I roll to a red light, the AC is cold. While I am sitting at the light AC is cold. But, once the light goes green and I start driving it stops cooling momentarily then cools just fine again.

Any ideas what this could be? High Pressure switch?
 
Joined
Aug 12, 2020
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277
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West KY
My Ridgeline has a brief interruption of cooling during any acceleration event that is more than granny level intensity. I'm guessing the computer is cutting out the compressor to reduce parasitic power consumption on the engine during acceleration.
 
Joined
Oct 7, 2012
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4,026
Location
Staten Island, NY
Nissan/Infiniti uses a variable drive compressor?
If that's the case, gauge readings are almost useless
Check airflow (condenser/cabin filter)
All cooling fan speeds work right?
Evac/recharge by weight is the only way to go on variable compressors
 
Joined
May 24, 2019
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234
Location
Ontario Canada
My Ridgeline has a brief interruption of cooling during any acceleration event that is more than granny level intensity. I'm guessing the computer is cutting out the compressor to reduce parasitic power consumption on the engine during acceleration.

My 99 Buick does the same thing so this set up has been around for a while. The computer temporaryly takes power from the compressor to ensure that the car can accelerate when under load. This does not happen with slow acceleration or at speed, but rather when giving it more acceleration pedal pressure such as when using the on ramp and getting up to speed for the expressway.
 

thescreensavers

Thread starter
Joined
Dec 21, 2009
Messages
775
Location
WPB, FL
Nissan/Infiniti uses a variable drive compressor?
If that's the case, gauge readings are almost useless
Check airflow (condenser/cabin filter)
All cooling fan speeds work right?
Evac/recharge by weight is the only way to go on variable compressors

I had no idea that was a thing, thanks! All fan speeds work and the fan speed never changes you just feel/smell the compressor temporarily shut off.

A compressor kit (drier, expansion, compressor, all new O-rings) is only $300 and a high pressure switch is cheap as well so I could replace everything but I want to diagnose before throwing parts :)

The previous owner did have the AC system vaced and refilled by weight in 2020 but not sure if he was having this issue then either.
 
Joined
Aug 12, 2020
Messages
277
Location
West KY
If you have a OBD scanning dongle and can watch intake manifold absolute pressure and throttle position in real time I would bet you will notice the compressor is cutting out when either the manifold pressure or throttle position go above a certain level.
 
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