So I posted a while ago about the radio power cutting out with A/C on and haven't experienced it since.

today I've noticed that it feels like a split second power drain (on high way) with A/C on. I tried to reproduce the problem with A/C off and wasn't able to. the drive is normal consistent pedal pressure and just feels like it lose some power and slows down.. car did not shift gears. can this be battery as well? or am I looking at bigger issue?

tx

 

It IS normal for a driver in a four cylinder, marginally powerful car to feel the extra load when the A/C cuts on. At least, that's been my experience over many years of driving.



According to this site,

performance - How much power (HP) do the components on the engine belt generally use? - Motor Vehicle Maintenance & Repair Stack Exchange

you will see ~5 HP for the A/C compressor, and a few more HP due to the alternator's providing current to the compressor clutch, rad fans, and interior fans.

So, I'd estimate that you may see an 8% drop in available power (the Fit is rated at 109 HP).

My more powerful cars don't exhibit this behavior.

 

someone suggested changing the battery.. will that help?

this seems to be more noticeable these days at ~ 100k

good thing fall is coming. I'm considering ditching the car over the winter

 

Changing the battery won't help with the A/C system requiring more power during operation....

Never hurts to check battery electrolyte levels after a hot summer...perhaps have the battery load tested too. But, don't just throw money at the issue. I'd check for poor connections at the alternator and battery, as I've found that aftermarket battery terminals are too small...they might be loose even though the clamp terminals are small & tight as they can go. <--if that's the case they simply need to be shimmed.

 

Just a quick thought, I would check to make sure the A/C pulley belt isn't slipping. Kinda hard to tell at highway speeds but try to listen for belt squeaks around town.

 

It sounds pretty normal to me. There is a small but sometimes noticeable decrease in power when the AC compressor kicks in.

I remember riding as a kid in a Chevy Sprint with a teeny three cylinder engine (rated at all of 60 HP according to wikipedia, if I'm looking up the right model) and an air conditioner. If you were sitting stopped at a light or something when it kicked in, the engine would jump from idle to what sounded like half throttle. If you wanted to get up a hill at something approaching the speed limit, it was essential to turn the AC off.

 

any chance changing spark plugs may help? could it be misfiring?

 

^^^ I doubt it.

If the issue concerns you so much, perhaps you need to have a mechanic or knowledgeable owner take a drive with you. They will advise if its an issue that you need to resolve.

 

The live data scanner can be used to watch the MAP reading while driving with ac on at steady 50 mph on flat road. The data can be written down and posted here. I am planing to do same for my car because on some days it is more lazy than on others