ECU Resetting

[fifthgear]

So, I've been told by K-KaT, aka K-DaWG, aka the KeWL one (and a couple others) to reset the ECU after installing my new intake. Now the logic behind this, to my understanding is, that once it is reset and you start the car back up and drive it, it will learn that it's taking in cooler air, more air, and will change the fuel-to-air compression ratio. This concept is simple to grasp, no?

Now think of this: the car already assumes (without an ECU reset) that it has the stock box on and already has a defined fuel-to-air ratio. Now with a new intake (and not reseting the ECU), it is getting cooler air and more air, but it doesn't have the ratios altered. Would it not be wiser to leave it this way, as you will still be using the same amount of gas before, if not a little less as you have cooler and more air going into the engine? The thought behind this is I assume is that if the engine is now taking in more air, won't it burn more fuel?

I hope this makes sense to you guys, but it was something that was proposed to me by someone else when I told them I was going to reset my ECU.

[DAILLESTWUN]

Yeah but you would think if you're not resetting the ECU then your CAI won't be working to it's potential. It's like adding a turbo and not messing with your fuel. it won't work how it's supposed to.

[jalmir]

The ECU will take it into account enventually, it's just that when you reset it it will also adapt itself to your driving style, so if you want it to be economical just drive it like your 90yrs old ... :D

[fifthgear]

LOL well then what does everyone think? Is it worth it? My buddy's Honda has saved him on gas after the CAI but he never reset the ECU. So I'm really wondering.. I can see how for a Turbo you'd need to, but an SRI? Will it really make that much of a difference?

[jalmir]

As I sadi your ECU WILL take the CAI into account, resetting the ECU only makes it faster for it to see ...

I always reset the ECU when I clean my K&N filter, it's not like I need to but I tend to let it take dirt for a long time! *shy* Last time I had to clean the filter twice! lolll

Anyway, I would recommend resetting it, it's not hard or long to do and you may have some fuel economy right away...

[Jonny666]

Basicly when you reset the ecu it erases all of its memory and restarts on a standard base map. it then adjusts for your climate and driving style. when you add a cold air intake with out resetting the ecu, the ecu will continue buisness as usual but it will see that the O2 sensor readings at the same load / throttle are differant than before. it will eventually adjust the fuel trim's to suit the change. it basicly comes down to pay me now or pay me later. the ECU will learn your mod, its a matter of time. also, while the ecu is readjusting to your new CAI there may be lean spots in the fuel curve..... if you think about it our beta II motors have an unusually high compression ratio for cars running on regular gas ie 10:1....our beta's also run very rich.... it is possible that the reson we are able to run such high compression safely on regular 87 gas is due to the rich fuel trim that the factory has deadlocked into our ecu's.
That's just my 2 cents.

[fifthgear]

I assume that once you do the reset, you must turn the car on and let it run for a bit? or drive it after you turn it on?

[KeWLKaT]

They hit it right on.

The ECU will EVENTUALLY adapt, but it makes the progress SO slowly you won't even feel it.

Also, go back and search a bit for those dyno threads from FordfasteRR where he used to be into his car.

Example (not real numbers):

Dyno run #1 : 129.4whp
Dyno run #2 :(ECU reset) 132.8whp

It is just proven that:

- When you do ANY mod, reset the ECU. It makes it start all over again, and adapt accordingly to the new changes.

- When resetting the ECU before a dyno run / drag race, it trims the fuel in a way to increase power output.

What have you got to lose anyways?

If you want good fuel consumption and whatnot, well, just don't modify your car, and shift at 2200 RPM all the time :D

I assume that once you do the reset, you must turn the car on and let it run for a bit? or drive it after you turn it on?

Just drive right away after it reached operating temp (that, I recommend to anyone anyhow for ANY driving)

[fifthgear]

Haha ok I will try this tonight then sir, right when I get home. And I might add, they always advertise that K&N and SRI/CAI will help improve fuel economy :rolleyes:

[KeWLKaT]

I've never believed that.

More air = More fuel = More burnt fuel.

I mean our cars have MAP and MAF sensors for a reason...

[fifthgear]

Yeah that's what I figured... well... I don't drive like a mad man so the gas consumption should be cool. I'm really curious though how long it would take the ECU to get used to the new intake?...

[mtlelantra]

FWIW, under daily driving conditions, I get 1.5-2 L/100 kms better fuel economy with my intake than stock (10 L/100 kms vs 11.5-12 L/100 kms), most likely because I'm probably getting better power and torque through the 2500-3500 rpm range where the auto tranny tends to shift.

[fifthgear]

FWIW, hrmm?

[KeWLKaT]

Possible, possible. I'm not saying it's not possible, but still. You are using less pedal to get where you're going. If you were driving with the same heavy foot (I know I see WOT and redline a lot daily), it wouldn't be such a good compromise.

Anyhow I really miss being N/A now that I have sunk soooo much money into the car, lol. Someone should've talked me out of the turbo when I was switching kits this winter :redface: :redface: :redface:

Maybe its just the fact that I have the broken exhaust... It's killing me with the noise and the restriction!!! Maybe when I get my **** together and get it welded I'll be a happy man again!

[fifthgear]

Understood. Hopefully I don't see too much of a difference in fuel consumption... unless for the better :D

[KeWLKaT]

I guess you'll let us know :)

Sucks you dont have a GT with the fuel consumption meter on the dash :D

[fifthgear]

Yeah I almost bought a GT - bastards, but it was rusted and damaged in a couple spots. **** that.

[KeWLKaT]

get a tib multigauge. :D

btw before you do anything else like this and go and spend 100$ for a friggen elbow and fliter, TELL ME. My SRI setup had only cost me 45$ with a reusabe filter :D

BTW if you need a heatshield for that filter, I have one made by Injen that I would sell!

[fifthgear]

Aww man now you tell me! I bought the SRI way before.. didn't you notice I was the one that created the DIY?

ECU Reset time. BRB with my opinions and success/failure.

[KeWLKaT]

ummmm

I did. LOL

But I didnt know BEFORE you bought it ;)

[ChrisS95TA]

So I reset my ECU....I think. Just did it with the key turned, I heard stuff going on when I put the fuses back in. Do I need to have the car running to reset it? Hehehe, I feel like a noob.

On my 95 TransAm I just left the - battery cable off for a few minutes and that did it. :tongue:

[KeWLKaT]

^^^ yeah that works too, but pressing the brakes accelerates the procedure ;)

[ricerrx7]

I've never believed that.

More air = More fuel = More burnt fuel.

I mean our cars have MAP and MAF sensors for a reason...

That is true, and if you're always at WOT then you will use more gas with the CAI vs stock. But, there are pumping loses to take into consideration. The stock intake is obviously restrictive, and the engine has to use power to suck the air in. With the less restrictive CAI, the engine has to use less power to suck the air in. Think of it like this; run a mile. Then try running a mile breathing through a mcdonalds coffee stir straw. You will use less energy breathing normally, because you had to use energy to breathe through that restrictive straw.

And all you have to do to reset the ECU is pull the two underhood fuses for a second. I proved this on the dyno.

[fifthgear]

Well I reset it, and I will be updating the DIY into it's publication mode :P

I instantly saw the change at low RPMs... more UMPH! Yay :D Thanks K-DaWG :P

Now let's see gas consumption.

[KeWLKaT]

Haha, glad you liked it :P

[ghrpdx]

Just drive right away after it reached operating temp (that, I recommend to anyone anyhow for ANY driving)
Waste of time and fuel ... I start the car, when (and if) all the warning lights go out, I'm gone.

[KeWLKaT]

the worse thing for piston rings is driving hard when the car hasn't reached operating temps.

unless you're talking about automatic tranny granny driving ;)

[fifthgear]

I'm confused.. what's going on now? :abovelol:

[Cypher]

always let the car warm up. this whole thread was about ecu resetting... wow...

[elantra_mann84]

so let me get this straight you reset the ecu disconnecting the negative terminal on your battery, breaking for approximately 30 seconds, reconnecting the terminal and then starting your car back up for a bit. then its done or am i wrong

[ghrpdx]

Yep, that's it ... then you get to reset your clock and all your stereo settings. PITA!

always let the car warm up. this whole thread was about ecu resetting... wow...
I'm sorry ... lost track. Fifthgear has started so many threads I can't keep track of which is which.

[elantra_mann84]

ok thanks guys for helping me out with all my crappy noob questions

[ricerrx7]

so let me get this straight you reset the ecu disconnecting the negative terminal on your battery, breaking for approximately 30 seconds, reconnecting the terminal and then starting your car back up for a bit. then its done or am i wrong
And all you have to do to reset the ECU is pull the two underhood fuses for a second. I proved this on the dyno.

Again. Just pull the two underhood fuses marked "ECU" for a second and the reset is done. Then you don't have to mess with clock and radio programming.

[jalmir]

^^^

What he says ... works great ! :D

[elantra_mann84]

well what works better remember i have an 03 with a maf sensor if that changes anything thanks for the help

[ricerrx7]

3rd times the charm?
Pull the fuses.

[Cypher]

both will reset it. its your perference.

[jay cam]

I had my SRI installed. So does this sound okay to reset the ECU.
Disconnect negative battery lead.
Wait for 30 minutes(keepbusy cleaning the car :rolleyes:).
Then after 30 min. push on the brakes for 30 seconds or 30 times and then start er up. Whats with the breaking anyway???????:confused: :confused:
Then finally drive for 30 min for the CPU to download new info.

Or just pull out the 2 underhood ECU fuses.

[elantra_mann84]

im taking it this is a hard concept to grasp

[fifthgear]

I'm sorry ... lost track. Fifthgear has started so many threads I can't keep track of which is which.


I keep seeing you post this. Do you have a problem?

[Kens GLS]

How often can you reset the ecu?

[jalmir]

I had my SRI installed. So does this sound okay to reset the ECU.
Disconnect negative battery lead.
Wait for 30 minutes(keepbusy cleaning the car :rolleyes:).
Then after 30 min. push on the brakes for 30 seconds or 30 times and then start er up. Whats with the breaking anyway???????:confused: :confused:
Then finally drive for 30 min for the CPU to download new info.

Or just pull out the 2 underhood ECU fuses.
lolll

you got it wrong ...

1. Disconnect the negative bat. lead;
2. Push the brakes for 30 seconds, it will drain the remaining electricity in the system!;
3. Reconnect the bat. lead;
4. Set your clock and radio;
4. Drive it for 30 minutes, the time the ECU needs to adapt itself to your driving style and the light mods.

OR

1. Pull out the 2 ECU fuses under the hood, just pull both out and connect them back, you don't have to wait AND you don't have to set your radio and clock;
2. Drive it for 30 minutes, the time the ECU needs to adapt itself to your driving style and the light mods.

Hope it's clear!

[jay cam]

Thanks buddy. Nice to see the procedure clearly explained.

[seraphim]

makes sense how do you do this

[KeWLKaT]

^^^ just explained it...


you people do it on purpose it seems!

[fifthgear]

Read above, there are several steps provided. Have a little trust in us, and yourself. It's a very simple procedure. If you use the method that removes the negative terminal, then when you put it back on there will be minor sparking - don't worry about it, just be cautious.

[BIGROB]

im stock and i would loooove to reset my ECU for no reason at all!!! :D ahhh jk but seriously how did this thread make it 3 pages? is it rele that hard to understand?

[elantra_mann84]

lol this is a pretty good thread it should be thread of the month