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Reset ECU/USMB


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16 replies to this topic

#1 CROSSTBOLT

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Posted 31 August 2003 - 09:01 AM

This is a newer, easier and faster Subie message board! You all done good! And thanks to Shawn & Josh for listening to my whining....

Reset my Baja ECU yesterday using the battery disconnect method. Looked in the Owner's manual about fuse panel and found NOTHING about ECU, did find TCU but my Baja has the 5spd MT. Got the 10mm boxend wrench & disconnected the ground for about 45 minutes. You would not believe the difference! I had a real crabby throttle: either accel or decel, NO smooth transition. You could NOT drive across a parking lot in first or second at a reasonable speed without being JERKED back & forth as it went accel/decel. And FORGET cruise! Uphill, upwind and level ok. NO slight downhill or it would jerk back & forth. Now it is smooth as glass.

I learned this reset ECU business right here with you guys & gals!Thanks!

Karl

#2 DerFahrer

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Posted 31 August 2003 - 11:01 AM

While I'm glad to hear it runs good again, I can't help but be curious as to why it was running like that in the first place.

You never got a CEL? The symptoms would have me checking the TPS thoroughly... :confused:

#3 CROSSTBOLT

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Posted 01 September 2003 - 05:12 AM

No CEL, just crummy throttle action. So where do I locate TSB's to browse?

#4 theotherskip

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Posted 01 September 2003 - 09:59 AM

i've always had pretty crappy throttle transitions, especially when trying to crawl in traffic. i always chalked it up to a poor gearing choices made by the engineers. i've reset the ecu (not specifically for this problem), but it has never solved it like it did for you. very strange...

it is next to impossible to leave it in gear while slowly rolling in traffic. you can take your foot off the gas to let it coast/slow down, but as soon as you barely touch the gas, it really starts bucking, even with feathering the gas ever so slightly. i've always just clutched it when i needed to give it gas again. i'd love to hear if there is a fix for this, besides reseting the ecu (which didn't help me)

#5 CROSSTBOLT

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Posted 02 September 2003 - 04:46 AM

Theotherskip, you're description is right on the money. Sorry to hear the reset did not work. And for Subielover2212 I was listening: you said TPS and I responded with TSB! I agree with TPS but I discounted it for an actual test since "the problem" does not occur in the same spot every time. That is, it seems to be a function of manifold pressure and not of throttle position.

The thing is still noticably smoother in transition from torque to trail and back again.

#6 theotherskip

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Posted 02 September 2003 - 05:13 PM

so you are saying that resetting the ecu completely cured you problems? i'll have to check out my throttle body, etc. i always thought that it was just poor gearing choices made by designers.

i've read through all the tsb's issued for my car, and none of them mention this problem.

#7 DerFahrer

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Posted 02 September 2003 - 11:49 PM

I have adapted to the jerkiness, I guess. I do occasionally make a very smooth transition from decel to accel, but maybe it's because my car isn't as bad, or I'm that good of a driver :banana:

I always claimed it was the good ole boxer engine torque at its finest...

#8 kehunter

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Posted 25 September 2003 - 12:08 PM

I posted a reply to someone else about this, but I saw this post and am confused by the acronyms here. What's a TSB and what's a CEL?
I'm having the same problem with the bucking and not being able to make a smooth transition from accel to decel. The service dept. guy at the dealership says it's the design of the car and that his Outback does it too. I had the computer reset the other day and tried to get the problem to happen again yesterday but couldn't, so it may have fixed my problem. I'm just curious what CEL is and what the TSB's are to search for my car. I'd like to be as informed as possible about this so I can make sure it's taken care of if it's a problem.
Thanks,
Kelly

#9 calebz

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Posted 25 September 2003 - 12:11 PM

CEL=Check Engine Light

#10 kehunter

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Posted 25 September 2003 - 03:18 PM

Thanks for the reply. Now I just need to know what a TSB is. Anyone? Or anyone have more input about this issue?
Thanks,
Kelly

#11 truktek2

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Posted 25 September 2003 - 03:59 PM

TSB = Technical Service Bulletin
This is literature sent out by the manufacturer usually to their dealers about common problems and fixes:banana:

#12 kehunter

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Posted 26 September 2003 - 08:14 AM

Thanks. Now how do I go about locating one of these TSB's? :confused:

Also, does anyone have any other info. on this problem?

#13 theotherskip

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Posted 26 September 2003 - 04:41 PM

i am not aware of any tsb's for this problem. i've searched for my car (a 97 obw). i still have to try cleaning out the throttle body and see if that helps at all. maybe tomorrow...

#14 CROSSTBOLT

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Posted 27 September 2003 - 06:29 AM

Whoa, ho, ho! I am the dummy that got screwed up on TSB/TPS. TSB: Tech Service Bulletin, TPS/TPI: Throttle Position Sensor/Indicator. There is no TSB on this ferky throttle as far as I know and my TPS must be fine because the "buck" showed up at different throttle positions.

I put another post in on easy ECU Reset that was inspired by Josh/Legacy777: pull the ECU fuse instead of disconnecting the battery. No ECU fuse? Pull the one for Eng Ign (engine ignition). I am inclined to believe it is a good idea NOT to use cruise for a couple of hours after resetting the ECU since cruise SEEMS to bring the jerks back. Fast. I reset again and drove manual throttle to let the confuser learn and throttle response is still smooth as glass!

#15 theotherskip

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Posted 27 September 2003 - 10:34 AM

Solved??

i just finished doing and oil change and cleaning out the trottle body. a few weeks ago, i picked up a can of Napa/CRC Fuel Injectoin Air-Intake Cleaner . this morning i stopped by a GM dealer and picked up a can of top engine cleaner, expecting the intake cleaner not to work.

after completing the oil change, i removed the air chamber (large plastic part of air intake before the throttle body). following the directions, i sprayed the air-intake cleaner into the throttle body as directed, then used a paper towel to clean out as much as possible. I then reapplyed more cleaner, and reassembled the air intake. it took a little longer to start, then ran a little rough for 30 seconds, but seemed normal after that.

i then took it to a parking lot and tried to get it to studder like it normally would. even when creeping along and then flooring it, it seemed to make considerably smoother transistions, worlds better than how it acted before.

i guess the true test will be driving to work on monday. i'll post with the real-world results after i've done some, but for now it seems solved.

if it continues, my next attempt will be to use the top engine cleaner...

hope this helps...

#16 newsooby

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Posted 29 September 2003 - 02:53 PM

Finally reset my ECU using the negative cable disconnect method -- wow what a difference!!

No more hesitation at 40mph/2200 rpm. Nice smooth shifts, even in traffic! :banana:

Dealer tune-ups couldn't fix shifting problems and hesitation :banghead:

I wonder why Subaru dealers don't do this when people complain about hesitation and shifting problems? Don't let the dealers hear about how well this works, they'll just charge folks for it!

Thanks for the tip!!

#17 theotherskip

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Posted 29 September 2003 - 05:50 PM

cleaning the air intake seems to have fixed my problem. driving in traffic to work today, and it is barely noticeable, world better than it used to be. it may be that resetting works for people with new cars, but for older engines that are carboned up, a cleaning with help fix things...




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