at the risk of exposing my ...


you are cruising at a certain load rpm and getting 15+, you ramp up a notch and the afr returns to 14.7, what would happen if you lean out those cells more?
could it be that at that juncture the open loop part of the map is less indicative of what you have on the map. just as later in the map the afr is WAY off what you have indicated on the map.

 

Changed the Accell enrichment, but wasn't able to log. Just watching the afr while driving I am not sure this solved the issue. Will log tomorrow morning for better information.

 

Hey Razorlab & JohnBradley,

What would you guys consider to lean for idle, and cruize. I noticed that over the past couple of days, when I start my car, the car wants to idle and warmup around high 15's, sometimes even very low 16's. I am a little nervous about this, so I pulled my plugs last night, but can't see any sort of real problems with them. The base of the plugs are black with carbon (Not badly though), and the center electrode is slightly whiter than before I changed to a lean cruise. The most noticable difference is in the metal tang, it's definately white(er) than before. Whenever I pulled my plugs before, they were always fine (Looking) with a subtle brown tint to them, and now they are just white indicating I am lean. (Which is good, but how "lean" is "too lean"?)

 

Logged the accell enrichment changes this morning and things look a bit better, but I am still unsure why it still reverts back to 14.7 at times.

The good news is that my last tank yeilded 23.6 mpg and I am normally between 21.5 and 22.5.

Log is attached.

 

anybody still using this technique?

 

Can't see how accel enrich can effect fuel econ. Unless your at a constant state of initial throttling which is impossible - kinda like going up hill constantly bothways to work.

Anyhow, 15.3 afr seems to make the most power for fuel. Two ways - run in open loop or lie to ecu with WB controller NB sim

 

I know this is old, but is has anyone had any negative affects from doing this? Has anyone fixed this so the AFR is around 15.4 for 80 MPH? Also has anyone logged the EGT for before and after this modification?

 

Any more progress on this?

 

looking at this again, and was wondering if the accel enrich parameter mentioned was the old discredited one that has been replaced with the newer revised deffs.
If so, what is that old parameter doing, especially at 3krpm onwards.
Have some US tuners continued to work this gas milage thing?

 

Also wondering if anyone was able to figure this out.I'm on e85 and i should be able to cruise at close to 16:1 with no difficultly. Can you force the ecu to always stay in open loop?

 

I have had great success with Open Loop cruising. Set the AFR for about 15.2 in my cruise range ensuring to taper it smoothly into the surrounding 14.7s. Timing is raised to about 40, again tapering smoothly out to whatever was normally there. Then the Open Loop load #1 and #2 are both changed to 35 in the cruise rpm with the rest left as stock values.

This is for 93 octane. I get easily 320 miles per tank of gas with normal every day driving. Even better for long highway cruising.

That is it....it is easy and works perfectly.

 

nm

 

I am on e85 and have raised the cruise timing up to 45 and will try to raise the afr to 16:1 and use the 35 in both open loop 1&2 in the cruise area. Once I get my car back from the body shop as a young kid in an escalade put it in reverse at a light and rammed into my car last night

 

So you are 93 gasoline? I was thinking of upping the timing with my leaner cruise but decided that the fuel should be burning quicker. Maybe thats not right ?

 

Yes, I am on 93. Sitting at my 1/4 tank from full and I am at 96 miles. Normal driving, occasional boost.