Like I said before, the 95-99 Maxima ECU is in fact different. I don't deny that, but the OBD-II programming and protocol is basically the same across all makes. I also don't deny that the ECU does in fact learn. I however don't agree that the ECU somehow reverts and starts taking away power over time. That just doesn't make sense. I also want to know why the G35 crowd insists on this procedure when the VQ35 Maxima/Altima crowd and the 350Z crowd don't embrace the same thinking.

As for gaining 5whp on the dyno by reseting the ECU, I've seen swings that high on my cars and friends car (various makes) with absolutely no changes to the car. Actually, I've seen swings as high as 20whp (friend's EVO).

 

I see the exact opposite. I see people with a lot of money and no tools in thier garage.

 

Okay, this is just BS. My 96 Maxima made a 167whp/183wtq with an intake back in 2000. When I was done with the car (modified stock airbox, y-pipe, JWT ECU, JDM variable intake manifold), the car made 205whp/200twq or about a 25% increase in whp. My ETs consistently dropped and MPHs increase with every power mod. The car went from 15.2s@92mph to 14.3s@99mph. I made well over 150 1/4 passes in that car and all it did was get quicker. I saw no proof of it getting slower or "detuning" itself. The car was ODBII and I didn't reset the ECU unless I had to change out a battery or if I got a CEL.

Yep, the information is correct. I think this link only proves my point.

 

What you state is exactly what happens when you reset an ECU. However, running rich is not what you want. A rich A/F will result in less power. An overly lean A/F will result in detonation which isn't good either. A nice A/F 15:1-13:1, depending on rpm and load, is ideal and this is where the engine will make the best power. Ideally, the most power will be made when the A/F is on the edge of detonation.

 

I agree Dave
What the hell!
Get this in your head guy's
If you guys think your cars came from the factory detuned your up in the night.
There is very little you can do to the ECU.
The best thing the ECU does is protect you from blowing up you engine When you think you are smarter than the factory. In some cases a reflash can help with timing and air/fuel.
A reset is just a reset. Put some good gas in your car and be happy.
Were does all this bull crap come from? And how does the ECU CHANGE THE CAM TIMING?

 

I just did the pedal reset on my 2003AT sedan with 40k (bought used in May) and it definitely changed the shift points, and got rid of the lag. I also chirped my tires (not from a standstill and had vdc on) for the first time, the tires also only have 7k on them. No this isn't the first time I've tried to chirp them. Normally it only would do it when I'm standing still and have the vdc off. I only use shell v-power and have no performance mods.

 

What the hell are you talking about. Enjoy your resets

 

The 350z crowd does have the same thinking. Do a search.

 

Ah okay, so you are saying everyone on this forum is stupid and your the smart one right?

 

Been dynoing VQ cars for 10 years, and have never seen a 5 hp jump from variables. Usually the 2nd dyno is always lower not higher due to heat.

And the VQ has always had a very exact power curve where it hardly ever changed. If there was a variable it was barely 1-2 hp. EVO's are not NA cars and can show a 20 hp decrease especially when the turbo gets hot.

There is no denying the fact that when people reset the ECU, they notice the gains.

There is already enough proof on this forum to back up the claim for ECU resets gain some power back. There is dyno proof, there are track times, etc. If you think there are no gains, back your statements up with proof. Until then its just your opinion. So please stop making it sound like its a fact when the facts are already laid out in the past that the ECU reset does work.

EOD.

 

Okay.

Did the ECU reset overnight last night. Left the battery disconnected for about 20 hours.

Purposely drove the car hard on the way to work this morning. Wound her up, manual shift mode, bat out of hell, shame on me. I deserved at least three tickets and my commute is only 11 miles. Fortunately I escaped unscathed and have already begged the law enforcement gods for forgiveness.

NADA. No difference that I could measure. The car still hauls cookies, still shifts the same, still moves at about the same rate. It's hard to tell (other than my impression) because I don't have any instrumentation to accurately measure the performance, other than the rate at which I see things coming at me through my windshield. Unfortunately I wasn't able to chirp second with my auto... But anyway.

Normally I'm a sedate driver. Speed limit, in the gas when I need to be and on the brakes the same way. Today I made it a point to run the car to see how it compared to the other times I've played a bit.

If there is a change, I missed it.

Still waiting on a reputable source, other than what's been posted in these and other public forums. Think I'll call Infiniti today and talk to my service guy and ask him to explain to me how the ECU learning and reset work from his perspective. If he's clueless (which I half expect) then I won't be surprised.

DaveB - your descriptions and scenario sound about like what I have experienced over the past two and half decades I've been messing with cars. There are some differences in terminology.

I believe the car adjusts to what it senses - no 'learning' other than the constants of what it senses each day. If we want to say that once a car 'gets used' to a certain amount of airflow (being sensed) and the ECU takes that vaiable and adds it into the equation, and we want to call that value a 'learned' value, then I guess I could buy into it, as long as we remember that the value could change (like when a mod is added). Then the ECU 're-senses' that value, adjusts itself, and proceeds as advertised. I believe the car does this on it's own (no reset required).

If Nissan didn't design the ECU in such a fashion as to be constantly adjusting to what it has been told (programmed) are its norms, the mod changes would be sensed (more airflow for example) and adjustments would be made and things would carry on. With this ECU I suppose that doesn't happen - it's constantly driving back to zero (or base) settings by adjusting for what it sees as abnormalities (more airflow for example).

I hope that made sense - I know what I'm trying to say it's just hard to write it.

Other than that - this sounds like a debadging discussion. One side thinks one way and the other thinks another and no amount of personal opinion is going to budge either opinion.

In the end it's all good. Reset or no, I had a good drive to work this morning.

 

I've been dynoing VQs for 7 years. Big deal. I've witnessed probably 20 VQs getting dynoed on Dynojets. With my own personal VQ, I've seen swings of 2-5whp. I've seen the same on other VQs too. The overall power curve shape stays the same, but the power can vary a little. I've seen better numbers on the 1st run and sometimes on the 2nd run. My shop typically does a 15 minute cool down with a big fan blowing across the motor before making another pass.

Hardly. My point was that the majority in this Org sub out the work on their cars, they typically have a lot of money, and typically have little understanding of how cars work. When they pop the hood, they get nervous looking at all the lines and electrical connectors and they have minimal understanding of how the systems work or even what they are looking at. I understand what I'm looking at. Does that make me smarter? Hell no. It just means I've read books, bought the FSM, done the wrenching myself, done the trouble shooting myself. That's all.

 

Hi Dave,

I've done "a lot" of dyno tests under very tightly controled test conditions and I must say a ECU reset can make a clear and unmistakable difference. (but not always) I've seen it make as much as 10 HP and sometimes up to 15 HP broad band deltas. Not just little spikes or blips, but significant changes in area under the curve. On my car the results are highly repeatable and definitly not coincidental.

Please see the text below... Its what I posted on another thread.
xxxxxxxxx
Guys I have to say that a ECU reset can indeed affect the power curve of the engine.
I've proven it on the dyno multiple times. It won't always do it... different cars will react differently. But I've seen that it can make a difference.

For example:
On EK's automatic a ECU reset made absolutely no difference at all on the dyno.
On my 6mt it fattens up the torque curve and HP above 4K. I've dynoed it multiple times.

Results will depend on how you drive, the gas being used and your cars state of tune. It doesn't always make a difference but the potential is there. You won't know untill you try.

 

An ECU reset at dyno time might make a seemingly large difference for the short term. You'll probably find that the car is running a lot richer during that time as the ECU is making decisions based on what's happening at that moment vs a history of what has happened with that particular tank of gas, taking into account the law of averages.

But give it a mile, two miles, everything will normalize again. I don't buy that the ECU adapts to your driving style. All it's going to do is change timing and air/fuel mix to make the car perform within the parameters defined in it's tables. It probably does this a lot more conservatively when armed with the last 100 miles worth of data to average out the numbers, and a lot more aggressively when it's starting at ground zero. But I propose that any changes perceived by an ECU reset are very short-term.

...Now, the computer-controlled automatic transmission. That's another story altogether. And one that I neither have theories or passion about.

 

+1

What he said.