Help! Losing power... - Toyota Yaris Forums

YarMinor · 01-09-2013, 07:39 PM

Hi, YW!

I have been having some trouble with my car. When I drive up to (or returning from) the mountains, I feel like I am losing power. The car seems to be struggling to maintain a reasonable speed. At points, I need to be flooring it to maintain 65mph on the highway, regardless of whether I'm going uphill or downhill. Then, when I have it floored, I think the car gets confused as to which gear it should be in, and quickly transitions back and forth between 3rd and 4th, causing a knocking noise sometimes.

It's the winter here in Colorado, but I don't think that it has to do with the cold. I think it has more to do with the altitude, because it only happens when I get higher up in the mountains. At first, I thought it may be an issue with the transmission, but it only has 35k on it. My other thought is that it may be an air intake problem (consistent with the altitude variable).

Does YW have any ideas? Questions? Please help!

clarenceie · 01-09-2013, 09:50 PM

Tire pressure would be my first guess since you are having trouble keeping speeds going downhill. Following that, How freely does your rear tires spin off the ground?

Decent engine performance on flat surface, good mpg?

In anycase, I had trouble keeping speed going uphill, what do you expect from a 1.5L? :P

CoryM · 01-09-2013, 10:24 PM

Could be a few things. Things that come to mind are:
-low fuel pressure (cause lack of power and fuel knock because it is too lean)
-barometer not working to compensate for the altitude change (not too common, and to be honest I don't know what the Yaris uses to sense altitude. Possibly the fuel tank pressure sensor?)

I would start by checking fuel pressure and volume.

Cheers.

PS: and yeah, don't forget it's a 1.5L. Flooring it to get over mountains is normal. On level ground not so much.

junorico24 · 01-10-2013, 03:01 AM

Higher up mountain means less air? Cars tends to struggle in those elevations above sea level. But I am guessing you check vacuum hoses and throttle body for leaks.

YarMinor · 01-10-2013, 04:10 AM

Clarenceie and CoryM,

I get that it's a 1.5L, barely pushing 100 horses. It's a 2007, so I've had the car for almost six years, and I know how it should normally handle [edit: having trouble making this sentence not sound arrogant; no bitchiness intended, I promise!] I've been up to the mountains before, and I know that it can maintain more power than I'm getting. The main counterpoint is that this occurs downhill, as well.

I don't think it's the tire pressure. I checked, and they look in normal range. This has happened the last time I went up to the mountains to go skiing, as well, but never in any other circumstance.

I think it's the altitude, but I don't know what I can do to fix that.... I live in Denver which is at 5,280 ft, and the base of the mountain (copper mountain) is 9,700 ft. I didn't think it would make such a big difference! I had the car checked recently, as I took a road trip up to Seattle and back (2,700 miles roundtrip), and there wasn't any problem at all.

Any suggestions to combat altitude-related power loss? Thanks again for all of the help!

YarMinor · 01-10-2013, 04:13 AM

***besides forced induction :p

Isn't there a chip out there that confuses the MAF into pumping more air?

CoryM · 01-10-2013, 10:21 PM

9000ft is pretty high to be making power. You would lose roughly 30bhp at that altitude. That being said, you should still be able to go 65mph on level ground w/o flooring it. It certainly sounds like something is wrong if that is the case, but pretty hard to guess what without some more info or data.

willygoodness · 01-11-2013, 05:25 AM

check the intake pipe bit before the filter box. maybe you've sucked up a sock or bit of plastic that is blocking intake

Bluevitz-rs · 01-12-2013, 09:50 AM

1. Check the Air Filter and air box for dirt. You should be able to see light through the filter when held up to the sun or a lightbulb.
2. Does your car loose speed coasting in "N" going down hill?
3. Have you checked the brakes to make sure one isn't seized? (you can do this very easily by feeling your wheels after driving, and knowing you weren't hard of the brakes. The wheel will be hot.

01-09-2013, 07:39 PM	#1
YarMinor Drives: 2007 Meteorite Hatch Join Date: May 2011 Location: United States Posts: 16	Help! Losing power... Hi, YW! I have been having some trouble with my car. When I drive up to (or returning from) the mountains, I feel like I am losing power. The car seems to be struggling to maintain a reasonable speed. At points, I need to be flooring it to maintain 65mph on the highway, regardless of whether I'm going uphill or downhill. Then, when I have it floored, I think the car gets confused as to which gear it should be in, and quickly transitions back and forth between 3rd and 4th, causing a knocking noise sometimes. It's the winter here in Colorado, but I don't think that it has to do with the cold. I think it has more to do with the altitude, because it only happens when I get higher up in the mountains. At first, I thought it may be an issue with the transmission, but it only has 35k on it. My other thought is that it may be an air intake problem (consistent with the altitude variable). Does YW have any ideas? Questions? Please help!

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01-09-2013, 09:50 PM	#2
clarenceie Drives: Yaris Sedan Join Date: Apr 2012 Location: So Cal Posts: 53	Tire pressure would be my first guess since you are having trouble keeping speeds going downhill. Following that, How freely does your rear tires spin off the ground? Decent engine performance on flat surface, good mpg? In anycase, I had trouble keeping speed going uphill, what do you expect from a 1.5L? :P

01-09-2013, 10:24 PM	#3
CoryM Drives: 2009 5-door, 5-speed Join Date: Sep 2011 Location: White Rock BC Posts: 687	Could be a few things. Things that come to mind are: -low fuel pressure (cause lack of power and fuel knock because it is too lean) -barometer not working to compensate for the altitude change (not too common, and to be honest I don't know what the Yaris uses to sense altitude. Possibly the fuel tank pressure sensor?) I would start by checking fuel pressure and volume. Cheers. PS: and yeah, don't forget it's a 1.5L. Flooring it to get over mountains is normal. On level ground not so much.

01-10-2013, 03:01 AM	#4
junorico24 Drives: toyota yaris yrs Join Date: Jun 2007 Location: Sydney Posts: 642	Higher up mountain means less air? Cars tends to struggle in those elevations above sea level. But I am guessing you check vacuum hoses and throttle body for leaks.

01-10-2013, 04:10 AM	#5
YarMinor Drives: 2007 Meteorite Hatch Join Date: May 2011 Location: United States Posts: 16	Clarenceie and CoryM, I get that it's a 1.5L, barely pushing 100 horses. It's a 2007, so I've had the car for almost six years, and I know how it should normally handle [edit: having trouble making this sentence not sound arrogant; no bitchiness intended, I promise!] I've been up to the mountains before, and I know that it can maintain more power than I'm getting. The main counterpoint is that this occurs downhill, as well. I don't think it's the tire pressure. I checked, and they look in normal range. This has happened the last time I went up to the mountains to go skiing, as well, but never in any other circumstance. I think it's the altitude, but I don't know what I can do to fix that.... I live in Denver which is at 5,280 ft, and the base of the mountain (copper mountain) is 9,700 ft. I didn't think it would make such a big difference! I had the car checked recently, as I took a road trip up to Seattle and back (2,700 miles roundtrip), and there wasn't any problem at all. Any suggestions to combat altitude-related power loss? Thanks again for all of the help!

01-10-2013, 04:13 AM	#6
YarMinor Drives: 2007 Meteorite Hatch Join Date: May 2011 Location: United States Posts: 16	***besides forced induction :p Isn't there a chip out there that confuses the MAF into pumping more air?

01-10-2013, 10:21 PM	#7
CoryM Drives: 2009 5-door, 5-speed Join Date: Sep 2011 Location: White Rock BC Posts: 687	9000ft is pretty high to be making power. You would lose roughly 30bhp at that altitude. That being said, you should still be able to go 65mph on level ground w/o flooring it. It certainly sounds like something is wrong if that is the case, but pretty hard to guess what without some more info or data.

01-11-2013, 05:25 AM	#8
willygoodness Drives: 09 yaris hb Join Date: Jul 2010 Location: qld Posts: 93	check the intake pipe bit before the filter box. maybe you've sucked up a sock or bit of plastic that is blocking intake

01-12-2013, 09:50 AM	#9
Bluevitz-rs 1NZ-6spd View User's Garage Drives: '05 6-Spd Vitz RS Join Date: Oct 2008 Location: Oshawa, Ontario, Canada Posts: 2,967	1. Check the Air Filter and air box for dirt. You should be able to see light through the filter when held up to the sun or a lightbulb. 2. Does your car loose speed coasting in "N" going down hill? 3. Have you checked the brakes to make sure one isn't seized? (you can do this very easily by feeling your wheels after driving, and knowing you weren't hard of the brakes. The wheel will be hot.