I just recently replaced my a/c compressor, condenser and waterpump on my 2005 Scion Tc with 112000 miles on it. I just did a road trip to OKC and got 304 miles on my full tank of gas when I had my a/c running. Under normal circumstances in the city with or without a/c before the install I got a minimum of 320 miles or so and usually 340+ on highways. I did not have any issues on my Colorado road trip earlier this month before the install.

It definitely seems like it slows my engine down considerably when I turn on the a/c. Has this happened very often? Is it due to buying an aftermarket compressor? It should be noted that my a/c does not work as well as it did, it blows cool, but not cold air now. I need to see what the mileage is without the compressor on, but it's still kinda hot.

Any ideas on what I should do to make it function better?

compressor kit I purchased off ebay. $345

http://www.ebay.com/itm/170637701841...84.m1497.l2649

Water pump $28
http://www.ebay.com/itm/150623855602...84.m1497.l2649

Condenser $75

http://www.ebay.com/itm/270930875499...84.m1497.l2649

I paid $450 to install everything.

 

Maybe the pulley creates more drag than the oem one? Like the bearing isn't as smooth as the old one? Change in elevation? Running it more? Gas mileage has a ton of ____ that could effect it

Sent from my SCH-I535 using Tapatalk 2

 

I still have all those oem parts on my car and I also feel a considerable loss in power whenever I turn on the a/c. I'm pretty sure it's normal.

 

Assuming the new compress is ok.

If you unplugged the battery, then the ECU is relearning.

I believe all ECUs have a Short Term Table/Long Term Table, where it adjusts timing/fuel accordingly. For the first few hundred miles.

Are the bearings ok in the new compressor?

 

I am pretty sure it is directly related to the Compressor. I never had any issues with gas mileage being below 320 mpg even driving hard core in the city. I estimate a 15% reduction in mileage when using the a/c. Will check the difference with using no a/c once it cools below 100 degrees after this week. Normally I averaged 26mpg normally and close to 30 highway. I barely got 25 on the highway using the a/c.

Edit:

Not sure on the bearings. Will have to see once I change out my drive belt soon.

 

not to brag about toyota, but it is possible the aftermarket compressor isn't as efficient as the toyota one (made by denso). and that is causing the drag on the power and fuel economy loss. It's a given the a/c causes a mpg loss, but not that much, mine is like maybe 2mpg when i use the a/c compared to when I don't.