Surprise benefit of resetting ECU

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BManning`

BManning`

Joined
Oct 29, 2005
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323
Well, I took the day off from work & finally got around to my LC "to do" list, triggered by CE P0155 (Bank 2 O2 sensor 1). I figured while I'm at it I'd also clean the throttle body, MAF sensor, and drop in a TRD air filter. Running boards off too; might as well as long as the compressor is fired up.

Thoughts: 1) I love the new look, sans boards...my LC no longer looks like a cabin cruiser. 2) Only difficulty I ran into at any time was getting the connector free from the harness on the bad O2 sensor; fought tooth & nail with it, from underneath and from through the wheel well, until I finally won. PITA. 3) Couldn't believe the amount of carbon buildup there was in the TB; STP, a toothbrush, rags, and elbow grease prevailed in the end. 4) MAF sensor looked fine, but cleaned it with CRC while I was in there. 5) Dropped in the TRD; my paper filter was dirtier than I thought-- hadn't checked it in a very long time:o

When finished, reconnect the battery & started it up-- as expected, idled high (~1200) for a few minutes before tapering down to ~700. Just got back from a test drive; it is smoother and more responsive...not an enormous thing, but enough to notice a difference. Very happy with the results, especially since...

Resetting the ECU has definitely improved the shift characteristics of the tranny! I suppose the TCU reset as well (logically) and now that little bit of rubbery slop I used to have between shifts is history-- shifts are much crisper and seem better timed than before. Unexpected bonus that I'm quite happy about.

Moral of the story: if your tranny shifts aren't to your liking, try disconnecting the negative battery cable for a little while...seems to have worked for mine. And if you're putting off cleaning your TB, call in sick & do it :grinpimp:
 
1loudLX said:
i'd like to clean out the whole intake manifold, i bet theres lots built up.
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How do you clean the intake manifold? I am changing out my starter this weekend and I could do it while I have it taken apart...
 
IIRC, the ECU sorta remembers your general driving style when you reset it, then it transfers that information into how the vehicle drives. this *could by why. i learned this from a friend of mine who would always reset his ECU and then drive really fast for a little while whenever he took his Lexus to the drag races, said it tricked the ECU into giving slightly more power since it's now "programmed" for a more aggressive driving style.

you could probably use some throttle body cleaner and a toothbrush to clean out the intake, dunno how deep you'd be able to get in there, but some is better than none. maybe even some seafoam. lots of elbow grease will help. i'm sure the ultimate way would be to take it off and go down to a machine shop to have it tanked.
 
Just make sure when you spray the carb cleaner in the intake the little straw doesn't shoot off inside :mad: .

I had my battery out for a few hours last week. Only thing that changed was my radio stations and clock. I guess I should unhook it again and drive like a mad man fir a couple days. Gain a few ponies. If that even works.
 
Engine power isn't increased, your ECT Computer just goes back into program mode and monitors your driving characteristics and then molds itself to your driving habits. For example, if you feather your throttle from the get-go after you reconnect your battery and then just baby your landcruiser, the ECT goes into fuel sip mode and trys to keep the trans in the highest gear possible and avoids hard down shifts and stuff like that. Floor it after you reconnect the battery, and alls it does is programs the ECT to have sharper shift points.

You know, you guys can do it another way without disconnecting your battery. Push the PWR button and it'll hold the revs a lot higher (redline) and it'll constantly downshift even when not needed.
 
Could this explain my mine feels slower and underpowered after cleaning the MAFS, TB and disconnecting the battery? I used a soft brass brush instead of a tooth brush. I figured it'd be fine since it's a softer metal than the TB's steel.

When I hooked everything back up it wouldn't start up. I had to give it some gas while turning the key to start it up. It turned over, idled high 1200 RPM before settling back to normal idle. It started up fine after that but it feels like I have less power now.

I'm wondering if the ECU got used to running on 87 octane gas and is now running as if it had 91.
 
^^Might re-check all the plumbing, sounds as you might have introduced a vacuum leak there^^
 
2000UZJ said:
Just make sure when you spray the carb cleaner in the intake the little straw doesn't shoot off inside :mad: .
.
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Haha I did that years ago with another vehicle. Luckily I got it out with some long needle nose pliers, but now I'm always paranoid when spraying the intake/TB.
 
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