Correct D15Z1 leanburn info

[drmiller100]

rather then fooling the sensor, just make a hot air intake.

[steffen707]

So I wonder if the WAI actually gives better gas mileage because of the warmer air, or because the engine reads "INCOMING WARM AIR". If the later is the reason, then why not feed it a incoming air is warm signal like all the time?

[VxonFumes]

@cbaber: I just read this now, but here's a thought for you: Do you have OEM wheel size? I had large prelude tires/wheels on my VX for about 2 weeks waiting for a chance to get winters put on them. This was a whopping 9.7% increase in outside diameter, plus much heavier wheels to boot. The car struggled much more to stay in lean-burn with those wheels on, b/c the gearing was too tall and had to struggle, and the extra reciprocating mass, etc, meant more work too. So this is just a thought: you cant' diverge much from OEM wheel size for gearing's sake.

Also, I just put a warm air intake on my VX, but it's too early to see if it works much yet...haven't had a chance to drive it yet. I'll let you know if it helps much that I can notice as winter is setting in here soon.

@greasemonkey: thank you very much for taking the time to give actual air-fuel ratios while running! Outstanding. You manged to keep the meter in the exhaust pipe while driving down the road? Did the 22:1 to 23.5:1 ratios hold steady all throughout the lean-burn operation, or was that just the most common averages?

John

[greasemonkee]

The tallest tire I've ran was a 185/65/14. I saw an improvement over the 195/50/15 - probably because of the width. Yes, it bumps up the effective final drive, but only minor changes were necessary in driving technique. My car has Integra brakes so original tires are not an option.

The wideband O2 is a permanent mount.



The factory wideband is very stable, nothing short of impressive. The air/fuel usually stays within one point while cruising, but it really depends on the conditions whether it runs in the low 22's or high 23's - not sure why.


Perhaps this will answer your other questions -

http://ecomodder.com/forum/showthrea...nda-23288.html

[nitebluesky]

thanks for the info on the rpms and when lean burn kicks in and when it doesnt. Ive just installed my D15z1 about a month ago and just installed a Hf tranny two days ago. My 02 is in the wrong spot thats for sure. Make sense thats why it has been acting up. ive installed it right below the firewall and this was after i didnt know that the 02 needs to be really hot to work. I had a Dx tranny before the swap and I got 41 mpgs kinda of curious what i would get with the HF.

[cbaber]

I've not been able to confirm that O2 sensor position is a factor. As I posted earlier, I swapped my stock exhaust manifold for another Civic setup, which the O2 is at the back of the manifold near the firewall. Even with that setup I could still engage lean burn. My problem is the O2 sensor. Shortly after making my earlier posts my factory sensor went bad, and I bought a cheap replacement. After buying the replacement I can no longer engage lean burn without the engine hesitating and stumbling when it tries to engage.

I've bought another manifold that moves the O2 sensor back up next to the exhaust ports, but have yet to install it. If that solves my problem then I will report back. If not, it's my cheap O2 sensor that cannot handle the lean burn.

[nitebluesky]

Mine engine light turns on when its cold outside, especially in the morning or when i leave it outside in the cold. Lean burn doesn't turn on at all or not for a while. Now that its colder i have to drive 15 or 20 miles of driving doing whatever. If i turn the car off and leave it sitting and start it up Ive got a 50/50 chance of it coming on again. When i did this swap last month same set up it was 75 plus degrees and my engine light never came on. Soon as the weather changed the 02 light came on. I am going to make a jumper harness hopefully soon and put it in the front near my engine and HOPE that will correct the issue of the engine light coming on.

[greasemonkee]

This does pose a concern to me now this issue is mentioned. As seen in the pic, mine is a few more inches away from the exhaust ports than the original config. Since day 1 the MIL would come on if I hit fuel cut right after startup - as if it had to be preheated before it would work properly. I've gotten use to the quirk and hadn't paid it any attention for some time, but after a quarter million miles, she's starting to jerk. That's probably a reasonable lifespan. Unfortunately, a sensor costs as much as the engine so it won't be getting replaced anytime soon.

[VxonFumes]

In relation to the brief discussion of tire size, there is a super tire sizing chart I found on another thread somewhere that is the best I've ever seen, found here: Custom rims, wheel tire packages for your ride - RIMSnTIRES.com

As to warm air intake, it is definitely better to make a warm air intake then to trick the computer by telling it the air is warmer than it really is. I used a warm air intake last winter, but it didn't seem to do much for me, but then again, I had tires/wheels on that were way too big for the VX and that hurt mileage so it was impossible to tell. I had to change an engine mount this summer and in the process had to remove some intake plumbing, and while at it just removed the whole resonator, etc, and put on a premium Amsoil EaA air filter with pre filter over it, so I had to lose the warm air. Maybe this winter I'll try again with proper tire sizes.

Greasemonkee, how many miles on your VX now? You got a quarter million miles out of your 02 sensor??? If this helps, I have an 02 sensor for my VX that I bought as a spare in January, as I had some mild stumbling issues too. A month ago I put it in the VX for one full tank of gas, and it made absolutely no difference for mileage or the stumbling, so I put the original sensor back in. The spare I got is a Denso, which is one of the OE Japanese companies Honda uses for its' components. I can sell the spare 02 sensor for 200 bucks or so, if interested: it's basically brand new, and clean. I just called a local Honda dealer here by me in Ontario, (Image Honda in Stony Creek), and they charge 380 dollars for that sensor before tax. I understand you have no reason to trust me to be telling the truth, but I can send pictures if that helps. I would keep if but I'm so tight for money 200 bucks would help me a lot. If your 5 wire 02 sensor is actually bad, a new sensor will do wonders for your mileage, and maybe clear up stumbling too.

(As a side note, if you're not going to keep your car up but let it go to waste, so to speak, let me know if you are ever going to sell it. I keep my cars up, and with a car like a VX it's totally worth the money.)

Lastly, who here has a good ECU for the VX, from a 94 or 95 model years for a hundred bucks? I'm looking. Thanks.

[greasemonkee]

Thanks for the offer! I'll be heavily pondering that.

Mine was originally a CX which I converted and modified to get the most that can be had from the leanburn system - there should be a link to that on the first page.


I try my best to keep the vx top shape - lot of irons in the fire lately, but because it's no longer a dedicated route car and only gets driven 45 miles/day; it would be years before a $390 sensor paid for itself. Every inch of this one is modified (ITR suspension, ect) and this one will probably be with me from now on.