Kolia

iTrader: (2)

The Subaru ECU does remember when knock occur. I'm pretty sure the Nissan also, but I cannot guarantee it.

@Nano: I don't see how the emission system would be adversly affected by an ECU reset. On acceleration and decceleration, signals from the O2 sensors are ignored by the ECU (Open Loop). But I'm puzzled by your friends CAT self-destruction. What type of car was that?

@Aki: Toluene certainly works. But you must keep in mind that most fuel might already have some toluene. Depending on regulations, pump fuel could have anywhere between 5 and 20% of tuolene or other parafin bases. Go above 30% and you might have a hard time starting up the engine. Health issues are also to be considered.

Octane increase from any given octane boosting product will not be the same when used with premium or regular fuel. Used with premium, we might get a 2-3 point increase in octane rating.

Reseting the ECU would put it in learning mode again. So yes, it might be a good idea. Get high octane gas, reset the ECU and drive it hard I usually reset mine twice a year, to adjust to summer vs winter driving conditions.

Nano

iTrader: (1)

Open loop occurs after given RPM during WOT, not simply "during acceleration". At WOT and after that given RPM, the ecu runs on it's predefined stock maps, curves, parameters, whatnot(fuel enrichment, cam timing, ignition timing, etc...). There is no learning going on as there is no data being read from any sensor(not even knock sensor as far as I know). And nothing can be altered here or changed or learned.

learning only is relevant to closed loop operation(part throttle and before given RPM). The ECU is always in learning mode, reset or not(it not only adapts to the driving parameters, but to ambient conditions as well). Reseting the ecu just gives you a clean slate to work with.

again, if the engine has been engineered to burn xx octane, why would it produce more power by burning xx+n?

SteveZ33

Update: My CEL light came on today. But I don't know if it has to do with the regular fuel (drove the car more today then when I got the gas the other night) or because of the Pioneer AVIC-N2 installation I had done today. I noticed it was on after the install.

Kolia

iTrader: (2)

The knocking occur the most during WOT. If the KS was bypassed then, the engine would risk grenading itself...

There is no mention of engine RPM as a factor to open/closed loop operation in the Nissan technical manual. It states that Open loop occure when:


Deceleration and acceleration

High-load, high-speed operation

Malfunction of heated oxygen sensor 1 or its circuit

Insufficient activation of heated oxygen sensor 1 at low engine coolant temperature

High engine coolant temperature

During warm-up

After shifting from N to D (A/T models)

When starting the engine


On a track, you can be sure the O2 sensors are completely ignored.

Kolia

iTrader: (2)

Have the code read. It could be anything from a fuel cap not tight enough to multiple misfires of the cylinders.

How does the car run? If its still smooth, it's probably just an emision issue.

I suggest, if you go to the dealer for that, not to mention anything about regular fuel in the tank...

Nano

iTrader: (1)

Believe me, It's not just "acceleration" and "deceleration", otherwise the car would always be in open loop, lol. Except on highway at constant speed. Throttle position and and RPM are factors (along with a few other).

Engine will not alwasy in open loop on a track, not even at dragstrip(launch)... unless the track is an oval and you never lift from gas and never shift. Otherwise, on a normal track, you are not always at WOT, the ecu is still learning and adjusting. Just rapid use of the throttle will get you out of open loop. I'd say on a lap the car will be 50/50 closed/open loop. But I'm no track expert, monza is more open, mecaglisse more close :P.

as for KS, as I said, I am not sure if it's bypassed. I deducted the reccomendations of not going WOT during break in and with low octane gas where in part due to that. Do race car use knock sensors? wouldn't make sense.


@Steve, you need to know what code you are throwing. (it could be detonation or something minor. Either bring it to dealer, or get it diagnosed. You can also diagnose it yourself, but it's a bit tricky. Here is what I found.

HOW TO SET DIAGNOSTIC MODE II (SELF DIAGNOSTIC):

1- Turn ignition to "ON" position and wait 3 seconds
2- Fully depress and release accelerator pedal 5 times in 5 seconds
3- Wait 7 seconds, then fully depress accelerator pedal for approximately 10 seconds until the MIL starts blinking
4- Fully release accelerator pedal (ECU has entered diagnostic mode)

The ECU will blink 10 times to indicate the start. After that, error codes are read by counting the blinks. For example, to read error codes 456 and 458, the ecu will blink 10 times, pause, blink 4 times fast, pause, blink 5 times fast, pause, blink 6 times fast, pause, blink 4 times fast, pause, blink 5 times fast, pause, blink 8 times fast, pause, lather-rinse-repeat.

HOW TO CLEAR THE ECU OF ERROR CODES:

1- Get into diagnostic mode
2- Fully depress pedal for more than 10 seconds and the ECU will only blink 10 times

Before erasing error codes, I would recommend finding out what they are. A 456 is a "very small leak in fuel evap system." I had that and that's usually caused by the gas cap not tightened down enough.

Kolia

iTrader: (2)

The Nissan Manual does not specify at how much % of throttle it will shift to open loop.

But in general, it’s only when coasting that the fuel trim and ignition timing is adjusted with O2 sensor feedback.

About the track well, you’ll get to experience first hand at Tremblant how it is. Only in fast, long sweeper will you be part throttle for any give length of time. The rest of the time, you’re either WOT or hard on the brakes. Long fast sweepers are virtually non-existent on North American road courses… So unless you’re chatting with your instructor, the engine runs in open loop. ;-)

I once had bad fuel during a track. Fuel at a shabby station, and their Premium wasn’t very good. The engine just died at 5000rpm coming out of a second gear hairpin. The tank was full and the car had nevers behaved like this before (at that track with good VPower!) This suggest the KS is quite active in this situation.

Nano

iTrader: (1)

I haven't got a clue on the track bit, I'll take your word for it, even though I cannot imagine taking turns at wot, I thought it was a smoother, gradual thing. Especially in chicanes or any curve that is not followed by a straight for that matter.

Fuel quality is a huge factor. What happened to you is strange, but not completely uncommon... I never had those issues(even with canadiantire gas). I fill up once in a while with 93 octane, for the "higher" guarantee of quality and cleaning properties... but never for added horsepower,lol. Even shell website says that V-power can range anywhere between 90-93 octane... actually, I am sure, that in most conditions(except odd rare cases), 91 octane will give the most power on Z. If you have detonation issues, it could be related to other things as well beside octane.

European and Japanese Z are rated at 280hp, and use higher octane fuels.

rolling

iTrader: (2)

uhh what does +1 and "bump" mean? i stillll havent figured that out ... *slaps head "should have had a V-6!"

CelticPride2

+1 = "I agree with what the quoted guy said" (+2 for the second dude who agrees, etc.)

Bump = "just making a post so this thread will get moved (ie, bumped) to the top of the forum listing again"

rolling

iTrader: (2)

oo ok thanx alot Makes sence now..

Kolia

iTrader: (2)

No cars in Japan are rated higher than 280hp. Manufacturers have agreed to not advertise HP higher than that. Regardless of actual HP (wich can be significantly higher).

The V-Power I used in Italy was 99RON octane (about 95 R+M). The "bad" fuel was some AGIP premium stuff (allegidly 95RON).

I must document myself on japanes race fuels now...

Nano

iTrader: (1)

Z have been dynoed in Japan too, they aren't producing significantly more power. Actually, they are producing less power than here, as emission laws are more stringent.

and it's not race fuel, it's japanese 100 octane pump gas (RON).

and Since 2002, European fuel has two grades(xcept germany who has 3), Euro Super(95 octane) and Euro SuperPlus (98 octane) premium would be 98 octane, not 95 Now Stop it! Never had issues with agip gas, and I beat the car way more than here.

Brandon@Forged

Japan's emission laws were unchanged and pretty lenient up until a few years ago. However, they are still not as tight as America's (CARB specifically). So I do not think Japan models are making more or less than America's. Nissan doesn't care as long as they can claim the 287 and 300 crank hp numbers and be close, and still pass emissions.