ecu tuning

[bagpipe goatee]

i've been meaning to invest in a chip burner, and i have a p06 laying around that i got for free. if anyone has a wideband o2, we could burn and test chips.

we could lean out the mixture a little, but not too much to where we damage the engine. the new civics have a "lean burn" feature, it'd be nice to learn more about that. i'm not sure where i should put this, because it is kinda an experiment, but i'm not doing it right now.

[SVOboy]

Recently I have been spending a lot of time on pgmfi.org learning about my little honda ecu and the kinda things you can do like changing fuel maps and all that stuff, and it really is a great idea. I want to do it I just can't afford the stuff.

In any case, that new lean burn you're talking about is the vtec-e, where the engine shuts off four of the intake valves to cut down on friction that really isn't needed. This first came about in 1992 in the civic vx and its d15z1. When I first went to the dealership and asked for an HX cuz I liked the epa ratings, they told me they had none in the few states around because they had no air conditioning and so no one wanted them. But, I did learn about this lean burn feature. My first thought was the crap out my o2 sensor to lean it out, but no. Then later on I learned about this 12 valve operation. I like that stuff, right now I'm trying to get some money to make the swap. In the mean time I will continue to learn about the ecu so in the future I can think about chipping and tuning air/fuel mixtures on the fly.

[Matt Timion]

Someone told me at the beginning of my gas mileage journey to "just make a new fuel map that is more efficient."

Easier said than done.

It was this (among other things) that eventually led me to the d15z1 engine. I figured I might be better off using an engine/ECU combo that is already maximized for fuel efficiency.

[SVOboy]

From what I understand the z1 had an air fuel ration of 14.7:1, which is exactly at stoich, so even with it's cuteness of being about to run vtec-e it could safely be leaned out a little bit more through chipping or tweaking the ecu a little. Though I think this is best done on the fly compared to always because of the way the engine employs vtec-e to begin with.

[Matt Timion]

You can use a SAVC to lean out the gas a little bit, but everyone has told me to not do it. I imagine that leaning it out a few percent might give you those few precious MPG on long road trips.

This is something I'll consider doing when my d15z1 setup is all done. I'll put in a SAFC and use it when I go visit family in Las Vegas. If I'm lucky I'll get an extra 3 mpg out of it.

[SVOboy]

3 mpg is nothing to scoof at in this non-hybrid non-european game we play. If I drove a lupo I would be the first to admit I'd be boosting all the time, because I'd still get 100 mpg on recycled fuel, so hell. But yep, ecu tuning gets into the damn expensive range, mehbe I will try to process something about it for an article upcoming --_^

[bagpipe goatee]

yeah, i guess you're right. also, sorry for posting this in the wrong forum. oh well.

[Matt Timion]

yeah, i guess you're right. also, sorry for posting this in the wrong forum. oh well.

Dont' worry about posting in the wrong forum.

I'd personally think it would be wonderful if someone could figure out a way to do this very thing. Chip ECUs to be more fuel efficient. I think it would be great if we could chip ECUs to have two fuel maps. One for normal driving, and one for "lean mode." Of course, in a perfect world, "lean mode" would turn on with the push of a button.

[SVOboy]

I figured I should revive this because it seems that Mista Bone's amazing 53 mpg in his 145 chp honda has a lot to do with tuning his fuel mixture. Anyone know anything about tuning for fuel economy? I've been trying to understand www.pgm-fi.org but it's just not working for me if you get my drift.

[Matt Timion]

Maybe the best thing you can do is ask someone there for guidance. I remember thinking of tuning my ECU for fuel economy, but it seemed like too much of a task for me to undertake. I guess that's why I went with the p07 ECU instead.

Honestly, there might be a good business in remapping ECUs for fuel economy. For example, they send you a ECU, and you send the same ECU back with a different fuel map on it that is set up for economy. Their cost? $50 or so. It might give them an extra 4 MPG, which adds up quickly now adays.

Just a thought. I'd be happy to help with the marketing of this service if and when you decide to do it.

I personally think it's a brilliant idea.

Remember that thread we saw a while ago where the guy said he pushes a button to enable "lean burn mode" on his ECU? now THAT would be something worth having.

[Flatland2D]

Matt, what have you heard about the downsides of leaning the mixture?

Is there anything special about this "lean burn mode"? Would fooling the ECU via the O2 sensor be accomplishing the same thing?

[Matt Timion]

Matt, what have you heard about the downsides of leaning the mixture?

Is there anything special about this "lean burn mode"? Would fooling the ECU via the O2 sensor be accomplishing the same thing?

I have no clue. Basically this is just like every other modification for gas mileage. It's full of supposed results and speculations. I personally think leaning out a car too much is bad, unless you have something else to replace the missing gasoline with (like hydrogen). I've even heard that using a K&N air filter results in a leaner mixture, which is why the MPG increases.

Honestly the last thing I want to do is take control away from my ECU. When I get my engine installed, it is designed and built for economy. the d15z1 engine is designed with the ability to go 20:1 or leaner AFR. Other engines are NOT built for that type of a mixture, so I'm not certain if leaning them out too much would be good or bad.

It's one of those things that people can talk about, but most people are afraid to do. I mean, who wants to risk damaging their engine? Not me. I guess any potential heat increases due to lean mixture could be overcome by using a super synthetic oil, but I don't know.

If I had an extra car, I'd try it.

[SVOboy]

I've just bought a brand new obd0 pm5 ecu for my auto to manual swap, and now I'm thinking about seriously working on this. You can get a willem eprom burner, and burn chips for the damn thing. I have heard that it is possible to lean out the mph ranges where you would cruise (like 50 and 65 mph) in my case to something like 16-1 or 18-1 on my engine, which would be lean but not lean enough to cause lots of heat or damage, so this would be relatively easy as it is just altering the ecus fuel map to inject less at those speeds, but I think if I do the resistor mod I would have to read the AFR at all times for some testing before deciding how to do the ecu tuning, however, a good tune on the ecu might allow you to leave the IAT like it was and just create the same affect on the ecu, which is much better overall.