ECU Reset

[AutobahnRacer]

I just want to know what the real point of resetting the ECU is. I did do research but all I get is posts about these ricer idiots asking if they should reset after every little mod such as ridiculous as changing spark plugs.

So whats the real and only true point in resetting the ECU?

[Ej6Mike]

Never heard of reseting the ECU after installing modifications. Only time ive ever unplugged / plugged an ECU back in is to reset any trouble codes (check lights) if i dont have my pocketscanner handy, or im too lazy to go inside and get it, lol. Of course, this is after ive diagnosed and solved the issue. Resseting the ECu also resets the Readiness settings in it (for inspection) , which have certain parameters that need to be met in order to read as "ready" ( for example... driving the car a certain amount of miles). This means you cannot reset the ECU while in line for inspection to clear a code in order to sneak on by (because the light wont come on for another XX amount of miles ) ...it will read as "not ready" and you will fail for emmisions.

[AutobahnRacer]

Trouble code reset makes sense, because like I said people were asking if they should reset their ECU after every little mod, and the OP said if you do major mods than you should reset, so I am just trying to see if its BS or legit.

Here was the procedure he posted:

The following is how to reset your ECU, which all Honda technicians do prior to returning your car from the shop:

step 1: Ensure the car is at opperating tempreature (i.e., take it for a drive or let it idle for a 15 mintues).

step 2: Take the fuse for the ecu out -- on my s2000 its labeled "Backup" but do research on yours because it could be different -- wait 15 minutes.

step 3: Put the fuse back in.

step 4: turn the car on. DO NOT TOUCH ANYTHING. GIVE IT NO GAS. let the car idle for roughly 15 minutes, or until the car is idling smooth at lower rpm's.

step 5: Turn the ignition off. ONCE AGAIN, DO NOT TOUCH ANYTHING OTHER THAN THE KEY. Immediately turn the ignition back on after you have gone to full off. this will store the new settings your ecu has made.

These steps will properly reset your ecu. After they are accomplished go do whatever, the new settings have been stored.
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[SovXietday]

It's bull****. They think that the ECU "learns" and this is false. The ECU does not learn, it just reacts.

[Nick 95 6sp]

In addition to the reasons already mentioned above, the stock ECU on the TT Supra (at least the post '93 version I'm most familiar with) does learn some things. For example, if it detects knock it is very aggressive at retarding timing as an initial protective reaction. So for people who consistently exceed "safe" limits of boost for the octane they run, with the ECU pulling timing it results in sort of a "wet blanket" feeling and the engine isn't as responsive or powerful as it could be. So if that happens and you reset the ECU, that resets the timing to the factory default (pretty aggressive) settings and that has noticeable beneficial effects in this situation. People who operate in a manner that causes this pulled timing consistently report quite a few mph improvement in 1/4 mile trap speeds by reseting the ECU.

[AutobahnRacer]

So in short don't even bother right/it does nothing? lol

ps I would personally never run boost under unsafe circumstances. Not worth the risk,cheaper for a proper tune than a rebuild

[Got Insulin?]

Originally Posted by Carministrator

ps I would personally never run boost under unsafe circumstances. Not worth the risk,cheaper for a proper tune than a rebuild

Tuning on a dyno or in the street is basically probing unsafe circumstances. Keep leaning til you knock; add fuel, reduce fuel; add boost, blow headgasket.

[AutobahnRacer]

Yea I know, but thats in response to him saying resetting essentially tricks the ECU. Thats like putting a bandaid on something that needs surgery. At least with a true tune once you find the safe perimeters its done and there.

[SovXietday]

Nick makes a point I should have probably mentioned. He's right, some cars have software built into the ECU that counts knock or something similar that will change the fuel and timing maps for the engines safety. I believe DSMs have this feature as well. Either way, it's really only a feature on a car that's usually boosted or has the ability to detonate rather easily.

When it comes to 90s/early 2000s Honda's, no. All the ECU knows how to do is read a bunch of different variables and output a timing value and an injector pulse width more or less.

[AutobahnRacer]

Are you referring to a specific situation or vehicle? What would classify as

has the ability to detonate rather easily.

?

[itwillboost]

Originally Posted by SovXietday

Nick makes a point I should have probably mentioned. He's right, some cars have software built into the ECU that counts knock or something similar that will change the fuel and timing maps for the engines safety. I believe DSMs have this feature as well. Either way, it's really only a feature on a car that's usually boosted or has the ability to detonate rather easily.

When it comes to 90s/early 2000s Honda's, no. All the ECU knows how to do is read a bunch of different variables and output a timing value and an injector pulse width more or less.

Just to add to that many piggybacks will have some ability to "rough tune" on their own.
For example to carministrator I know there is no difference between my cars 1997 and 2000 ecu minus 4 certain pins but the responsiveness and ability to adapt are drastically different. What I am trying to say is this can be a very specific and specialized answer to the question.

[DB Dude]

lol. there is no "risk" to resetting your ECU (simply pulling a fuse or disconnecting the battery terminal for a few minutes). Whether you will get any benefit depends on how your ecu works. Either way, its a precautionary thing to do if you are significantly changing any of the aspects that would affect the performance of the motor. Its more of a "you never really know, so best to err on the side of caution" type thing. For example, when I change plugs I always reset the ecu because there is a good change that the gap on the plugs is not exactly the same as it was before. For "learning Ecu's", it will "erase" the memory of whatever fuel map was running before, and adapt to the new circumstances to find the stoichiometric AFR. But there is no harm that can come from it, so its kindof pointless to NOT do it.

However on an side note, OP - do you not realize the irony of referencing a bunch of "ricer idiots asking if they should reset after every little mod such as ridiculous as changing spark plugs".............. and then you post a thread asking if you should reset the ECU? LOL. You're not going to find a conclusive answer here, I will tell u that much. Every ECU is different, every owner is different. Certain times its recommended to reset the ECU, other times its not.

[ThePrimerSuspect]

I think its pointless. I've never done it on my cars or customer cars unless it was necessary. Resetting because you replaced something is a waste of time, but if it makes you feel better then go for it. It can't hurt.

[jpalamar]

I wouldn't waste your time.

[AutobahnRacer]

Alright general consensus is don't bother, so I won't.

[SovXietday]

Originally Posted by Carministrator

Are you referring to a specific situation or vehicle? What would classify as ?

More or less referring to a car that if you were to put 87 in instead of 93 you'd probably det like crazy. Mostly boosted cars.

itwillboost, yeah some piggyback systems can "rough" tune, but only AFRs and they need a wideband O2 in order to do it, and they will only do it in low load areas. Basically they just make small corrections to try and reach a target AFR that you have specified, but they will always be monitoring and doing this, so resetting it isn't going to get you anywhere.

DB, not sure if you really know how the ECU works lol. The ECU doesn't know "omg, he just put on a catback exhaust. INCREASE FUEL AND TIMING YO!" No, lol. Most ECUs are unable to make significant adjustments, if any, in the positive direction. (As in, increase timing and fuel for better performance after an intake install). It's a computer, and it is limited to the software installed and how it is programmed. Same with gapping of spark plugs, that has nothing to do with tea and china and an ECU to be honest. The ECU only tells the coil when to release it's charge to the spark plug, not how much electricity to send.

All in all, no, it's useless unless you're trying to clear a code / get it out of protection/limp mode. If you're making significant changes you need to switch to an EMS system (piggyback, standalone, whatever) that has the ability to make the additions to fuel/timing that you need manually.