Hey guys, I have been experiencing this issue for as long as I can remember...
Basically what's happening is when I turn the ac on, or fan on, the car noticeably requires more throttle than it usually would.
Now I know that by engaging the fan or ac, the car is working harder, but is this a normal behaviour?
I find there is quite a difference in how the car responds when the fan is off, when compared to when it is on...

My clutch is the original clutch, and currently I am at 168,000 km (104,000 miles) or so, and it does require replacing soon....does my clutch condition have anything to do with this?
I've also noticed that the car shifts harsher when the fan or ac is on. Like it requires more time between shifts and when letting off the clutch, and shifts are still not smooth.

2007 6mt. No mods

Thanks!

 

No, your clutch has nothing to do with it; and if the car has been driven reasonably conservatively, there is no reason why it should need replacing soon.

Regarding the A/C, I've seen calculations which indicate compressors draw between five and ten hp from the engine, so yes, when the compressor is on, the engine should feel a bit sluggish.

Regarding the fan (without A/C), no, that shouldn't draw enough to be felt, errr, unless you are talking about when you have the defrost cycle on which engages the A/C compressor regardless of whether A/C Mode is selected or not.

I have a 6MT as well, and in line with what I wrote above, my car (and all ten manual transmission equipped cars I've owned prior to it); I feel a slight drag from the A/C compressor, and zero drag from just the fan.

 

sounds good horeseshoez. really appreciate it!
I'll double check if the fan being on has any effect....
and the car seems to have been driven pretty conservatively, the owner before me was the original owner and an older gentlemen who got all maintenance done through the dealer
I know the clutch will go to 200 easy, since I don't abuse it either....but just for peace of mind I'm thinking of doing it sooner. Don't want to test the limits of it and then one day have it crap out on me.
Also, right now my car is jerky in first gear....and I've read that it can be attributed to a faulty APP sensor....should I replace that now or just wait and see if the clutch job makes the jerkiness go away?

 

I'd replace the APP sensor now. I just had to replace the clutch on my car, and the good news is it is highly unlikely to just "crap out"; mine started slipping nearly 20,000 miles before I finally replaced it.

 

is there anyway to ensure that the jerkiness is caused by the APP sensor before replacing it?
like I don't want to replace it if it isn't broken/faulty....

 

Not that I know of. That said, I haven't looked into the APP sensor to see if there is any way to diagnose if it is fully functional. Maybe someone else can chime in here on this one.

 

I think there is a way to see if the APP is bad by putting it in cruise control mode and slightly increase the speed using the accel feature to see if the accel is smooth.

I had to replaced mine since it too dam obvious, it drove a WRX lol under 3500 RPM I got massive "lag" with the same throttle input past 3500 rpm its pull like on full throttle. Replace the APP solved this stupid issue.

 

the cool thing about modern cars, ours included, is that the compressor turns off at WOT, but only at Wide Open Throttle.

 

I think it turns off if engine RPM rises at a fast enough rate.

WOT in 1st gear or WOT with the clutch in, for example.

I don't know if it turns off at WOT in like...3rd or 4th (or 5th or 6th) gear or something.

My S2000 and TSXes operate that way, anyway. The AC compressor clutch just disengages if the RPM climbs at a fast enough rate. Or at very high RPM. I think its based on pressure differential sensors inside the AC comp.

But if I floor it...say...in 4th gear at 3-4K RPM, the AC comp stays on.

Anyway, OP, its normal to notice engine drag with the AC on. The compressor and AC fans in the engine compartment turn on together...so that be your correlation.

Its also normal for the shifting to be more tricky. The engine RPM falls at a faster rate between shifts because the engine has a load on it.

 

interesting!! Alls I remember is that when I was about that WOT life, the air would blow warmer during the high speed jaunts.


Now, I'm all about that 65MPH life. safe cruisin' for me!!

 

In "theory" if the APP sensor is giving you issues, it would be in any gear, not just 1st. It may be more noticeable in 1st due to gearing. There are a couple of threads that go into the details of testing with cruise control. Mine was jumpy/jerky in 1st, but I could for sure reproduce it in 2nd and 3rd driving through a neighborhood at a steady speed.

 

common with the 6MT esp if the A/C system is low on refrigerant, there's a restriction in the system (stop leak used) or the compressor is on it's way out!

 

is there a way to know or diagnose the compressor? would recharging the a/c unit solve anything?

 

put a pressure gauge on the low pressure side and measure the pressure

 

Check the pressures, but you have to remember that it's not going to be 100% accurate since our system is based on weight!

 

You know...I have never noticed this on my TL. It may be because the number of seconds the accelerator is actually to the floor is way lower than on my previous slower vehicles?? I do remember this behavior on my much older automatic cars, but don't specifically remember it on my manual cars. Very good chance my memory is just gone considering I have had the TL for 10 years now...and haven't owned an automatic vehicle since '96.

 

The very first car I ever had with air conditioning was a 1981 Audi 4000 4MT with a 5-Speed transmission. The car was slower than dirt, doubly so when the A/C was on. While playing with the car I discovered a button on the floor under the accelerator pedal, and when said pedal was pressed all the way to the floor, said button would get depressed which in turn shut off the A/C compressor. Unlike our 6MT TLs, that car pretty much had three modes for the accelerator pedal, 1) off (foot on brake and/or grade descent), 2) steady speed (partially depressed), 3) any level of acceleration or grade ascent (pedal flat to the floor).

 

Sounds like what you are experiencing is totally normal. The A/C puts a load on the car so it is going to seem sluggish, there may be times while you are accelerating and the a/c compressor cycles off and you feel a surge in power. I wouldnt replace anything until it starts to act up. It doesnt appear the APP sensor is acting up just based on what you said.

 

Most hondas/acuras cut off the AC compressor when the RPMS rise above a pre-determined amount. I think with the TL it's around 4500 RPM...

 

I can confirm the A/C blow warmer air when you WOT, its happened in my AT TLs too.

 

Thanks everyone for the replies! There continues to be a wealth of knowledge on this forum which is priceless!
I tried the cruise control method momentarily and it seemed okay, will have to remember to try it again with more road and time next time around.

also, for those who have mentioned testing the pressures...how does one do that? lol

 

^^^ go to a indi shop they will hook up a gage that measure on the low and high side at the same time when your not running and it provide a live data as your compressor kick in, also they can see any else might goes wrong with your A/C system like stuck expansion valve etc....

A/C system is complex and its wasn't mean to DIY (unless you are mechanic).