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Old 03-28-2012, 04:42 PM   #20 (permalink)
EcoModding Lurker
Join Date: Mar 2012
Location: Houston
Posts: 46

truck - '06 Chevrolet Silverado WT
90 day: 22.65 mpg (US)
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Originally Posted by California98Civic View Post
I have a scan tool that I bought for diagnostic purposes, and it offers some data my ultra gauge does not. But since I don't have a MAF sensor, I would not have that data on the tool either. By "spark" do you mean a timing advance readout or something else? Because the timing advance data would be inaccurate once I jump the system and start changing timing at the distributor.
Yes by 'spark' I mean spark advance, most tuners have these tables it's what you may know as a 'low octane' or 'high octane' tune (all that's changed between those two tunes is the spark advance). Yes, honda's use speed density, tune by MAP sensor, I'm not very familiar with honda ECU's when did they go over to MAF or have they yet? Its actually very easy to tune speed density system if you had some type of software that would allow you to change the ignition spark while keeping your idle spark/idle circuit stock, which is the ideal situation. Sadly I see no spark map parameters on the hondata tech website, which I assume people are adding aftermarket ignition systems for boost retard or N/A advance at certain rpm? Like I say don't know too much about these honda ECU's.

I have thought about Hondata, and looked into it. My specific OBD2 ECU is not ideal for their services, though other 6th Gen Civic trim levels are (such as the EX). I wish I had a 2005+ HX. Its redesigned ECU is specifically cited as one that Hondata will tune for MPG if desired. That would be cool.
I'm not positive but I'm pretty sure your ECU is supported:
Applications By Vehicle
Though they may not send out a 'gas mileage' generic tuned ECU, you'd have to do it yourself. By the mid 2000's I'm sure they have spark advance maps available, but you never know with honda, it seems like if something works they don't change much for a few decades.

One feature that would greatly benefit your goal is the hondata fuel tables, you'd have to buy a hondata tuning system and a wideband O2 sensor (PLX about 150$ last I checked) and have access to a good laptop, this would allow you to really lean out your engine, or within a certain rpm range/throttle input etc. You can save different tunes on your computer or wherever, so if something doesn't work just modify or start over from stock tune. Leaning it out from its current 14-14.7 (assuming its in good running condition) to 15-16 AFR will net a few more mpg's, the trick is to lean out the AFR until just before the catalytic converter/narrowband O2 sensors tell the ECU to add more fuel so the cat doesn't burn up and gas mileage decrease from the ECU adding fuel. Harder to explain than it is in practice.

Technical Information
Tech - Wideband tuning

Civic 96-99 US D16Y P2P P72,P28,P30,P61,P08J,P30J,P72J s100/s200/s300 2,6,7

Civic 96-99 US D16_ P2E P74,P75,P06,PR4,P72,P28,P30,P61,P08J,P30J,P72J s100/s200/s300 2,6,7
2. Manual transmissions only.
6. OBDII to OBDI adapter harness required.
7. OBDI ECU swap.

- if yours is a manual, seems like you can use the hondata with an ECU swap and adapter, call hondata for details if you go that route

Last edited by mja1; 03-28-2012 at 05:18 PM..
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