This one is for you modded guys - we all know the VQ35DE ECU tries to compensate for mods that we have installed. The question is, do any of you routinely reset the ECU?


I also remember some posts about the car stalling out due to intake setups (pop charger, etc). Of those with stall-out incidents, who reset the ecu and who did not?

 

I'll start it off - Had the pop charger installed with grounding kit for about 2000 miles, no problems to date, never reset ECU.

 

I reset it everytime I get a new mod.

 

Mod list below. The car has never stalled, nor thrown a CEL. I have not ever reset the ECU.

 

i havent reset it at all....

 

So has anyone noticed a power loss over time? Thats probably my main concern here. Ahhh I hate OBDII...

 

don't have to reset it every month, just reset it after a new mod

 

never reset it yet. havent noticed any power loss.

 

No power loss here either. Consistent .2 sec improvement in 1/4 mile and +2mph at the end. Never once resetted the ECU.

 

No notable power loss.

 

No, that would be stupid. The ECU adjusts its fuel maps to keep the O2 sensor reading from going rich or lean. It also adjusts its timing maps to just before knocking would occur. Both are desirable things.

When you reset the ECU, the maps are reset to default values which are not optimized for your particular engine and mods, but which the factory chose in order to keep the engine safe. In other words, the fuel map will be too rich, and the timing map too retarded for best engine performance. It takes about 150 miles of driving for the ECU to then retune the maps to optimium values for your particular car.

So periodically reseting the ECU just guarantees that, for the next 150 miles, the engine won't run right. Note that any time you make a mod which affects fuel mixture or timing, it'll take the ECU about 150 miles to adapt to it. Until then, performance will be sub par.

 

Never reset it... Dyno has been consistant all the time.

 

Interesting point, thank you for contributing to this thread.

Just curious, how did you come up with the approximation of 150 miles? (Where did ya hear that, not that I dont believe ya!)

 

It is in the emission control section of the manual.

 

Guess I'll chime in now...

I installed the Kinetix Plenum V4 w/o reset...felt great! I then reset the ECU...didn't feel AS great anymore

I went to the track the next day, about 16 hours after the reset and the best I could run was 14.29 and the best my friend's z ran was 14.28. Our cars are bsaically identical except he has a pop charger and no plenum and I've got a NISMO CAI and plenum. So yea...don't know how I feel about that ECU...

 

So then, the ECU really doesn't negate our mods over time, does it?

Also, how does it supposedly cancel out our mods? Im thinkin A/F Ratios, right? Maybe timing?

Which leads me to believe if we get a piggy back AFC, we can keep the stock unflashed ECU and control it ourselves.

I smell progress being ready to be made...

 

how long can it really remember it for? a week? a month? more than a day seems unlikely just because if you consider it as an average, eventually there would be so much info it would take weeks to even make a minute change to the overall settting.

my opinion, the reset is a placebo effect, if that. unless you reset it constantly, meaning every time you start the car, thus running at default settings 24/7(which as mentioned might not be so great at all) your going to quickly hit the same settings you would have without the reset.

 

[QUOTE]Originally posted by Jetpilot718
So then, the ECU really doesn't negate our mods over time, does it?

No, it doesn't.

Also, how does it supposedly cancel out our mods? Im thinkin A/F Ratios, right? Maybe timing?

Again, it doesn't, but the things it does control are the air-fuel ratio, timing, and throttle position.

Which leads me to believe if we get a piggy back AFC, we can keep the stock unflashed ECU and control it ourselves.

The only time a piggyback could help is if your mods push the engine outside the range where the ECU can compensate. An example of that would be adding a supercharger or turbocharger. I can't think of any external bolt on NA mod that would push you outside the range of the ECU's maps (changing cams, or installing a stroker kit could push you outside the maps). However, you might still want a reflash to raise the RPM limiter, the speed limiter, or the WOT setting (the stock ECU will only open the throttle to 85% of WOT). Technosquare offers a limited reflash for that.

 

[QUOTE]Originally posted by ares
how long can it really remember it for? a week? a month? more than a day seems unlikely just because if you consider it as an average, eventually there would be so much info it would take weeks to even make a minute change to the overall settting.

The manual says it takes about 150 miles of driving for the ECU to fully adapt to changes. For example, if you switch from running 91 octane gas to 93 octane, it'll take about 150 miles for the ECU to advance the timing up to what 93 octane can support. Also, if you were to drive from sea level to say Denver, it would take the ECU about 150 miles of driving to adapt to the thinner air.

my opinion, the reset is a placebo effect, if that. unless you reset it constantly, meaning every time you start the car, thus running at default settings 24/7(which as mentioned might not be so great at all) your going to quickly hit the same settings you would have without the reset.

Correct. The only thing a reset can do for you is to start the ECU learning from a known safe condition, ie rich A/F and somewhat retarded timing. That's not a bad thing if your mods have leaned out the engine too much.

 

good info shopdog , thanks