ZoomZoom

Hello All,
I don't know if you have looked at the thread posted
ECU Reset gave me .4 second increase in performance and fixed AC

Modifry - what's your take on this?? Obviously, I value your opinion a lot...

Seems like a pretty easy thing to do but I don't want to damage anything.

Tim and JRaw, if there is some truth to this, it may be worthwhile to try during the next dyno run.

Cheers,

modifry

I don't know for sure how the Honda ECU operates, but on a lot of vehicles it goes like this:

ECU comes from factory with default settings, with usually includes ignition timing at maximum advance.
As the car is driven, fueled, abused, etc, the ECU watches for detonation or engine knock. If it hears knock, it will retard the timing till it goes away. This is a fairly slow process, may take a few miles (10-100) of driving to make the changes.

Some ECU's will continulally try to up the advance to see if the condition that caused the knock (low octqane gas?) has gone away, and if so, they will return to factory specs in a few hundred miles.
Other ECU's may react faster or slower, depending on how they are programmed.

If someone runs crappy gas and the ECU retards the timing, it will affect HP. If you reset the ECU, BAM, you have max timing advance again. If there is no reason to retard the timing, it will stay there, but if you're still running the same crappy gas, it will slowly return to the retarded state. (I think that's called "Alabama")

This is how some bogus performance product companies get dyno tests to show a HP gain. Their instructions tell you to install their "Super-whammy-dual-douche-bag-turbo-flow-fan-blade", and to make sure your ECU "compensates for the increased air/fuel efficiency" they tell you to reset your ECU. When you do, you may actually notice the performance increase if your vehicle is old and tired and abused. BUT, it is knocking it's ass off and over the next hundred miles, will be back to it's old (slower) self again.

If we get enough time on teh next dyno day, it would be very interesting to try this with several different cars. Make a few runs, then reset the ECU, and make a few more comparison runs.

I've never put anything lower than 92 octane in my car, and I've never heard it knock, so timing should be at full advance.

I'd also like to go to the next dyno day and try manually activating VTEC at a lower rpm, just to see what happens.

SilverStreak

And then I'll bring some Everclear to pour into our tanks... that is if Modifry is out of liquid O2...

ZoomZoom

Modifry,
That is an interesting analysis.
At one point, while I was still in Houston, I accidentally used the middle grade (87) gasoline. I never had any problems but it now makes me wonder if my ECU has retarded the spark AND if it managed to learn it's way back to full advance - or if I could actually benefit (1-2hp) from doing the unplug and resetting procedure?????

I may give it a try before our next dyno to see what happens.

Thanks for the feedback.

SilverStreak

Id like to know HOW to do that...

johnyboy32

I think there is something in the FAQ section on how to reset the ECU. If I remember correctly, it is not complicated.

modifry

Worst case (and this is how it's usually described), you just disconnect the negative battery terminal for 10 minutes, then hook it back up. Of course you lose your radio presets too. If you want to keep your presets, unplug all the connectors from the ECU instead. ECU is the big box behind the left panel in the driver's foot well. It's probably easier to re-do your presets.

modifry

After thinking about the original post, it mentioned the ECU reset also fixed the guy's AC. In that case, the ECU probably retarded the spark because the car overheated (or it thought it did). In that case the ECU may shut down the AC just to reduce the load on the engine.

SilverStreak

I may do it just for fun since my 'Check Engine' light came on 2 days ago and I suspect the gas cap...

Cosworth

I don't think it applies to S2000 ECU. You guys have a more "up-to-date" technology that adjusts to any problems in matter of seconds. Older OBD-II ECU's are known to necessitate resetting, but S2000 ECU does not require resetting AFAIK.