BSOD2600 Posted September 30, 2006 Share Posted September 30, 2006 I'm going to school in Klamath Falls, which is around 4300ft. I've noticed a few things about how my car changes with the elevation: 1) When I romp on the gas, typically the car switches into 'power mode' and takes off. When in kfalls, this does not happen. 2) There is a weird buzzing/humming sound thats most noticeable around 2-3.5K (until the tranny shifts and the rpms drop). It changes with speed. Initially I thought it was some problem with my transmission (I'm pretty sure its slipping or something anyways), but this weekend I drove back to a sea level city and I don't hear the sound anymore (or it's still there just not really noticeable anymore). 3) The engine often revs up to 2K when in drive or reverse to get the car moving. Then all of a sudden, it engages and the car jerks in the direction. This a sign there are problems with the transmission? Yea, this isn't an elevation issue since it happens all the time. The transmission was swapped out with another 89K mile AT 2 weeks ago. 4) Obvious lack of power compared to sea level -- yea, I realize this is normal because of the elevation. Are there some changes the ECU makes based on the MAP sensor or something? Quote Link to comment Share on other sites More sharing options...
porcupine73 Posted September 30, 2006 Share Posted September 30, 2006 have you checked the atf level? maybe it's low? based on your descriptions, it sounds like the replacement AT's oil pump might not be all that hot. If it really is slipping it's not going to last long. As you already noted, you're just not going to get as much power at higher elevations because there engine can't get as much air (and consequently fuel) when romping on it as it can at low elevations. Quote Link to comment Share on other sites More sharing options...
Scoobaroo Posted October 1, 2006 Share Posted October 1, 2006 A normally aspirated engine will lose around 3% H.P for each 1,000 ft rise in elevation. At 4,000+ feet, you're down about 12% compared to sea level. Quote Link to comment Share on other sites More sharing options...
BSOD2600 Posted October 1, 2006 Author Share Posted October 1, 2006 My Legacy has a turbo. What I ment about the power mode, is with my automatic tranny, there is actually a power light that turns on. Up in kfalls, I've never seen the light turn on when WOT. That's why I'm asking if the ECU changes anything with elevation. Quote Link to comment Share on other sites More sharing options...
ericem Posted October 1, 2006 Share Posted October 1, 2006 My Legacy has a turbo. What I ment about the power mode, is with my automatic tranny, there is actually a power light that turns on. Up in kfalls, I've never seen the light turn on when WOT. That's why I'm asking if the ECU changes anything with elevation. Well i see mine come on every so often at lower gears, but usually when im on the highway it lights up. If the fluid is a little bit low, it can casue the clutches to slip and therefore its screwed on that part, but the turbo should help u out a bit. Hmm never thought about height on earth. Hmm, well is it like a super noticeable problem? THe power light i believe indicates to hold the gear, and downshift. Quote Link to comment Share on other sites More sharing options...
ericem Posted October 1, 2006 Share Posted October 1, 2006 Just wondering, u try premium fuel or do u run premium fuel all together? Becasue these engines run way better one premium, its even noticeable with my 93 leg wagon non turbo. Like i got my REAR wheels spinning!! THATS incredible, and on the highway, its definitly more quick. Then i went back to 87 octane, and things just dont feel the same. But if u say there is a buzzing or humming from the engine, well, its hesitating, mine did the same sort of thing, dumped the seafoam through the pcv valve and no more humming and buzzing. ANd dumped some seafoam in the gas tank. Quote Link to comment Share on other sites More sharing options...
BSOD2600 Posted October 1, 2006 Author Share Posted October 1, 2006 Yea, I only run premium fuel -- the gas cap says to. As for Seafoaming, yea I've already done that too. Had a lifter sticking and it fixed it :-) http://www.ultimatesubaru.org/forum/showthread.php?t=64947&page=3. I checked the ATF levels the other day and it seemed fine. Although, being that the tube for the dipstick is angled, it seems like some fluid would rub on/off and throw-off the reported level. Whats the proper way to check it? Cold/hot, etc? Quote Link to comment Share on other sites More sharing options...
ericem Posted October 1, 2006 Share Posted October 1, 2006 Yea, I only run premium fuel -- the gas cap says to. As for Seafoaming, yea I've already done that too. Had a lifter sticking and it fixed it :-) http://www.ultimatesubaru.org/forum/showthread.php?t=64947&page=3. I checked the ATF levels the other day and it seemed fine. Although, being that the tube for the dipstick is angled, it seems like some fluid would rub on/off and throw-off the reported level. Whats the proper way to check it? Cold/hot, etc? Oh ya i remember that thread. I checked the tranny by driving in the city, for about 10-15mins then i stopped left the car running(dont turn off the engine) then i made sure the car was on level ground, pulled the dipstick, wiped it, then reinserted, it should be around half way on the hot side, of the dipstick. Quote Link to comment Share on other sites More sharing options...
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