Honda Accord AC Drain on Power

[steve20]

Originally Posted By: buster
I don't know, could that also contribute to the power/hesitation/bucking issue? Once the rpms hit 2.5k + the car surges a bit. Doesn't seem normal. Have to go above 3.5k rpms to really move smoothly. The lack of power is highly annoying.


I have the same car with approx the same mileage, only mine is an automatic. You are describing EXACTLY, to a T, what I go through with the AC on.
My remedy: turn the A/C off for a few seconds while I accelerate from a stoplight. The A/C must be pulling at least 20 hp from the 160

 

[TFB1]

Originally Posted By: johnachak
Originally Posted By: buster

All maintenance is up to date on this car. 1 o2 sensor has been replaced. Valve adjustment about 50k miles ago. Nothing else I can think of that would cause this.

My suggestions would be:
Maybe dirty, map/maf sensor, and/or throttle body.
Maybe plugged, dirty injectors? In most cases I have seen neither will necessarily throw a code but the hesitation/stumbling will be noticeable. Good luck.


This^^^^^^^^^

Common cause for lean stumbling issues on high mileage vehicles...

Originally Posted By: steve20
The A/C must be pulling at least 20 hp from the 160


At low speeds, the engine is only making a small percentage of it's rated HP... Sounds like the engine is running poorly enough that it's probably leaving much of the HP back at the barn...

 

[Rand]

with a stick shift and a 4cyl thats probably only making 20-30hp at 1000rpm it can really be affected by a/c

example my subaru is rated at 175torque.. its lower below 1500rpm so say 150(this number isnt factual)

150x1000rpm/5252=28.6 hp

next factor in stickshift starting uphill with A/C on and it definitely makes me drive the car totally different with AC on and off..

the rpms also drop 2x as fast when changing gears if the AC is on.

 

[mechtech2]

Many cars with AC actually SLOW the return to idle [so it won't stall, I guess].
Makes it harder to shift - it can make you feel like a beginner!

 

[The_Eric]

Originally Posted By: TFB1

At low speeds, the engine is only making a small percentage of it's rated HP... Sounds like the engine is running poorly enough that it's probably leaving much of the HP back at the barn...


Originally Posted By: Rand
with a stick shift and a 4cyl thats probably only making 20-30hp at 1000rpm it can really be affected by a/c

example my subaru is rated at 175torque.. its lower below 1500rpm so say 150(this number isnt factual)

150x1000rpm/5252=28.6 hp

next factor in stickshift starting uphill with A/C on and it definitely makes me drive the car totally different with AC on and off..

the rpms also drop 2x as fast when changing gears if the AC is on.


Also don't forget that an engine's rated HP/TQ @ whatever RPM is achieved using wide open throttle. You can't figure low speed and part throttle HP/TQ figures off of the WOT values.




Originally Posted By: mechtech2
Many cars with AC actually SLOW the return to idle [so it won't stall, I guess].
Makes it harder to shift - it can make you feel like a beginner!


Agreed. It seems to me that Ford Rangers are bad about this.

 

[Rand]

Well the car only needs so much air. not much difference between WOT and 1/3 throttle at 1000rpm.

but I'm not arguing your point.