When tuning highway mode stuff in $61, should I allow the mixtures to sit a bit lean or should I stick with the 128 BLM/INT rule and tune like that? I have noticed that the upper parts of the BLM table will have several cells consistently with BLM>129. I tuned a lot of that out, but I have since decided that those cells may end up involved in the highway cruise stuff and should be a little lean.
Highway mode = lean cruise mode, right?

 

IIRC the ecm is jsut in open loop, learn disable, or whatever you wish to call it so the blms will be locked at 128 and the ecm will be running with a commanded AFR of whatever you set in the tables for HW mode. Youll need a WB O2 to tune in/check up on the actual AFRs as teh stock O2 will be of little use.

 

How did I know I'd need a WB? Man! I guess that's the next contestant up on the Price Is More than I Can Afford.
Thx, dimented24x7!

 

When highway mode is on, learn is off and the current BLM cell is used... isn't it? It's been a really long week and I've had less than 4 hours of sleep each nite for the past week.
I would definatly use highway mode but don't tune too lean because it can hurt milage! There is a limit where too lean and you'll be using more throttle = more engine load = bad milage. A wideband should be required for any kind of AFR tuning outside of closed loop narrow band stuff.
Driving back from Detroit today my upper radiator hose blew off the engine. Short story; easy fix at gas station where I needed to fill up anyways, but I did something stupid. I washed down the engine and I think I thermo shocked the oxygen sensor into failure. Car gets less than 20mpg right now on the highway after it set the SES light. But it runs great after the SES light comes on and the BLMs are set to 128 . If only I could get highway mode to work while in open loop!

 

That would be cool. Is it possible to command a particular AFR in C/L?

 

At least that makes some sense. What I never understood is why the CCP have to be taking place for HW mode to occur? Whats teh point?

 

Run open loop and forget the closed loop strategy.
Run the AFRs you want everywhere.

 

I've been toying with the idea. Especially now that our Formula SAE competition is over and I can get my wideband in MY car . I had to use the RR_WB to tune the car on the test track. It was logged into our PI data-aq so I could chart everything at any sample rate required. We did 20hz for the wideband tuning group.
One thing that keeps me from going open loop is the fact that I haven't even messed around with the prop gain terms for the sensor. Yet the engine runs awesome in closed loop AND open loop. The gas milage is just great on the highway so I was going to wait until I worked on tuning a super stable low idle in closed loop. Once I do that I'd like to start tuning open loop.
I have a couple of EGT TCs and I'm thinking about putting the narrow band, wideband, and TC all next to each other in the y-pipe. Data log and see how accurate the narrow band sensor can be when temperature compensated. The narrow band is a heated sensor but it doesn't have a temperature control, it's just used to get the sensor up to temp faster and keep it from cooling down.
Bruce, do you know where TRC is? It's in Marysville and we test and tune our cars there. One of these weekends you'll have to come out and check out my "really fast" car. 470lbs and 86hp .

 

[QUOTE]If I could figure out how to do it, I would. I don't YET have a WB, but that may be soon in coming. Got any ideas?