Hey Scotty,
I have an ‘18 Kia Sportage with 67k miles on it. It’s been hassle free outside of routine maintenance. However, something I’ve started to notice is that the engine feels like it has “low power” when turning the key in the ignition and shakes/rumbles ONLY WHEN I have the AC turned on. There is no extended cranking or rough idle, it just feels like the engine has just enough power to start and shakes/rumbles as it turns over. When I start the car and the AC is off, the problem disappears. What could be causing this?
Turn the AC off
This NEVER dawned on me 🤯🤯… I’ve been starting it with the AC off as a precaution… but if u read my question I Didn’t ask if I should turn the AC off I asked what could be causing this on a 4 year old vehicle.
😉
A weak battery can do that. Start with load testing the battery and alternator.
Battery was just replaced with a duralast gold a few weeks ago actually. So I know it’s not that
Looking at the photos on rockauto.com it looks like the compressor on that vehicle has no clutch and instead uses a control valve. The control valve or its associated circuitry may be defective, causing too much drag from the compressor while the engine is cranking. (You'd want minimum drag from the AC compressor when cranking. On a clutch-type compressor the clutch would not engage until the engine starts.)
Thanks for the tip I’ll check it out!
It's the same kind of symptom you'd typically get on pre-computer cars if the AC was left on while cranking, you wind up with the starter trying to run the air conditioner as well as crank the engine. You should still check the simple stuff first though like making sure the battery and battery terminals are OK.