Doug, Don, Guys,

Last night I spent quite a bit of time re-reading portions of the Engine Control (EC) section of the service manual. Based on their detailed description of how it works, I believe the ECU is constantly learning in both closed and open loop modes. This seems to confirm what many of us have noticed while driving our cars under "real world" conditions.


DaveO
2003 G35 Sedan - DP / Willow / AT / Premium / Sport
350Z Engine Cover, T-Stat & Air Duct / Stillen CAI
GG 7-Wire H-G Kit / TechnoSquare ECU
Street Edge TC / B&M Cooler / Stillen Exhaust

 

Dave, did you notice any distinction in the service manual between "open loop" and "wide open loop"? Again, I will be asking for clarification, but the comments I heard seemed to suggest that W.O.T.="wide open loop"=no learning. It may be that W.O.T. is the ONLY time our ECU isn't learning??

P.S. Should have put the manual on my xmas wish list, darn!

2004 | 6MTs | Diamond Graphite/Graphite
Upstate NY

 

Doug,

I found no reference to a "wide open loop" control function. Normally WOT stands for "wide open throttle".

For those with a 2003 Sean Service Manual, the basic info on Closed and Open Loop Control is found on page EC-26 of the Engine Control System section. Disclaimer: I haven't read all 644 pages in the EC section of the manual. There may be other references or information I have not yet found.


DaveO
2003 G35 Sedan - DP / Willow / AT / Premium / Sport
350Z Engine Cover, T-Stat & Air Duct / Stillen CAI
GG 7-Wire H-G Kit / TechnoSquare ECU
Street Edge TC / B&M Cooler / Stillen Exhaust

 

What I was trying to say is that (only) when at WOT, the ECU may be in neither open nor closed loop, but rather a third (non-learning) condition which was referred to as "wide open" loop. I'm note sure that even makes sense but, with my limited knowledge, that's how I interpreted his comments. For the moment, another one of Life's little mysteries I guess.

2004 | 6MTs | Diamond Graphite/Graphite
Upstate NY

 

I know the Stillen does, don't know about the Borla though. I heard that the design for Borla was different and perhaps there is an X or H chamber in the muffler? Don't know fill in the details! thanks

 

Doug,

I did a brief follow up and found no WOT mode. I believe I read and re-read the text correctly. Essentially "Closed Loop Control" is in effect while the car's crusing. Open Loop Control is in effect under the operating conditions listed below:

1 - Starting the engine
2 - After shifting from "N" TO "D"
3 - During warm up
4 - Acceleration or deceleration <<<<
5 - During high load or high speed operation <<<<
6 - High engine coolant temperature
7 - Malfunction of heated O2 sensor 1 or its circuit
8 - Insufficient activation of heated O2 sensor 1 at low coolant temperature

The next topic following Open Loop Control is "Mixture Ratio Self-Learning Control" which I read as functioning during both Closed and Open Loop Control Modes. The description describes how "Short and Long Term Fuel Trim" works.

The next topic "Fuel Injection Timing" addresses Sequential Multiport Fuel Injection (normal mode of operation) and Simultaneous Multiport Fuel Injection (starting and fail-safe mode). The text continues with no mention of a non-learning mode. I guess we could call the Fail-Safe or limp-home mode as non-learning.... however, Nissan doesn't.


DaveO
2003 G35 Sedan - DP / Willow / AT / Premium / Sport
350Z Engine Cover, T-Stat & Air Duct / Stillen CAI
GG 7-Wire H-G Kit / TechnoSquare ECU
Street Edge TC / B&M Cooler / Stillen Exhaust

 

More sound/vidoe files
lead_foot just posted some pics and sound/vid files here

https://g35driver.com/forums/showfla...sed&sb=5&part=

You will need Quicktime 6.5 to hear the files. Get it here
http://www.apple.com/quicktime/download/

Worth the download. Hearing these has sold me on the purchase.

 

Before performing Idle Air Volume Learning, EC-42 of the 2004 sedan service manual states:

"...make sure that all of the following conditions are satisfied. Learning will be cancelled if any of the following conditions are missed for even a moment.

- Battery voltage: More than 12.9V (At idle)
- Engine coolant temperature: 70 - 100 Degrees C (158 - 212 Degrees F)
- PNP switch: ON
- Electric load switch: OFF (Air conditioner, headlamp, rear window defogger)"

Q.) What is a PNP switch?


2004 | 6MTs | Diamond Graphite/Graphite
Upstate NY

 

Good points Doug. I forgot to include that valuable info.

The PNP switch is the Park - Neutral - Position Switch for AT equiped cars.



DaveO
2003 G35 Sedan - DP / Willow / AT / Premium / Sport
350Z Engine Cover, T-Stat & Air Duct / Stillen CAI
GG 7-Wire H-G Kit / TechnoSquare ECU
Street Edge TC / B&M Cooler / Stillen Exhaust