Sorry if this is in the wrong forum, I posted it here as you can use it as a tool to tune a naturally asperated or turbocharged car. Anyways I got my air/fuel ratio meter working, I was able to make it out of a programable chip and a few custome circuits. Basically how it works is there is 5 menus that you can cycle through by pressing a button. First menu displays the air/fuel ratio (2 decimal places) and the maximum and minimum air/fuel ratio that has been reached. You can change the time interval in which the air/fuel is metered at by pressing a seperate button, and you can reset the max and min values by pressing a different button. Second menu contains basically the identicle thing only displaying RPM's instead of air/fuel. Third menu has a stopwatch, you can time whatever u want with it (works just like any other stopwatch, start/stop and reset). Forth menu is the data logging menu, you can start it, then at wide open throttle go through all the RPM ranges and it records all of the data at the given increments you want (which you can also change). The last menu (5th) is the data viewer, where you can view all the data you just captured from the previous menu. Using this you can adjust something like an SAFC, etc. You could also type in the values into an excel spreadsheet if u wanted for a graph of rpm's vs. air/fuel ratio and tune from there. This device also hooks up to a computer and can log the data as well. Anyways I got everything working perfectly so far (for the rpm's I made a frequency generator so I could test to make sure it was working properly before I hooked it up to the car. The frequency meter on the thing I made works perfectly I just havent hooked it up to the car yet). I made this for a 2004 Elantra which already contains a wideband o2 sensor, so basically all I had to do was hook it up. I was also curious if other people would be interested in something like this? Since I got the prototype working I can make a new one but much neater, enclosed in a box, nice connectors, buttons, containing instructions, etc. I am not exactly sure for the price at the moment but I do know that it would be considerably less than most other wideband o2 air/fuel ratio meters, and it works exactly like it should. Anyways here are a couple of pics of the process, it is ghetto rigged a bit, and the numbers you see in the display are not actually being read from the car, they are being read from a test signal:

Picture of the device while still working on it
http://mahonroy.home.comcast.net/af001.jpg

Another picture
http://mahonroy.home.comcast.net/af002.jpg

Closer picture reading test signals
http://mahonroy.home.comcast.net/af004.jpg

Pic of the device rigged up in my car so I could test it out
http://mahonroy.home.comcast.net/Photo001.jpg

Pic of me
http://mahonroy.home.comcast.net/af005.jpg

Let me know what you guys think, and if any of you would be interested in a nicer version of this. There is also a lot of different things I could add to this, such as different LCD screens, more memory, different features, etc. I was looking in on how to go about modifying airflow signals, because it would be nice if you could have meters, get rpm vs. air/fuel ratio data, and tune all on the same device, the only thing I am looking into/afraid of is if the device fails how to have somekind of a fail safe device.
-Matt

everything looks great except that gh3ylord in the last pic ! LOL

good stuff :) how much for a nice version? :D

Wow! pretty slick -- nice work!

I have a suggestion if you want one -- if you could rig it to be a Heads-up display (reflected off of the windshield) and include MPH on the readout, that would be even cooler.

That's sweet. All you people with 04's & up are lucky. By the way, 11.24 A/F sucks, haha.


Wow! pretty slick -- nice work!

I have a suggestion if you want one -- if you could rig it to be a Heads-up display (reflected off of the windshield) and include MPH on the readout, that would be even cooler.
Heck yes, you'd need a different display to do it... and it'd have to be bright enough for you to be able to read it all the time. But that would be cool.

That's sweet. All you people with 04's & up are lucky.

You would be able to use this on other years of elantras as well, you just need to get a wideband o2 sensor to go with it.

Yeah. I don't think I'm ready to do that. Next thing you know I'm gonna want to turbo the car.

I am now trying to locate the ECU Harness for the 2004 Elantra but am having some difficulties... I have completely removed the glovebox and glovebox holder, but now I cannot find the ECU or the ECU Harness, could someone help me and tell me how to find it? :D Also, once I find the ECU Harness, I know there are several pin diagrams out there labeling what pins are what, but I was unable to find a pin diagram for the 2004, they seem to be different. Does anyone know of where I can get a pin diagram for the 04? Thanks again for the help.

The ECU is under the drivers side dash, that is why you can't find it on the pass side.

Well... aint that some **** lol. Yeah I looked at this thread: http://www.newtiburon.com/forums/showthread.php?t=3623 which made me under the impression it was there. :crash_com Thanks for the info!

What does the mafterburner do??

It basically has the same purpose as the s-afc, its a fuel controller, you can adjust your air/fuel curve with it. I was just using that as an example as to where the ecu harness is located at because the mafterburner taps into some of those wires, plus I thought the tiburon would have a similar location for things, aparently not though.
I found the ECU, its in kind of a wierd hard to reach location with a bunch of other harness cables running over it, getting in the way. May be a pita to get to it, but I will take my whole dashboard apart if I have to, to get to the wires I need :rolleyes:

so with this baby you can tweak the ecu??? or it just monitors it

so with this baby you can tweak the ecu??? or it just monitors it
Are you talking about the thing that I am making or the MAFterburner? The thing that I am making right now only gives you information, I am still figuring out about making it a fuel tuner. I know how I would do it, the only thing I need to figure out is a fail safe device.

NEW:
Ok, call me stupid but I cannot get the connector off the ecu for the life of me. I don't want to put much torque on it as I don't want to mess the harness/wires up. There is a plastic housing that connects to the ecu, then there is a plastin harness that appears to plug into the plastic housing. The only movable piece that I was able to locatate was at the end of the harness u can pull out a clip, but after a while it gets harder and harder to pull the clip back and I am afraid of breaking it. I also cannot tell if just the harness thing comes out of the plastic piece, or if it is actually one piece that comes out of the ecu... Anyways here are some pics, I circled the movable clip with a red circle, if anyone has any input on how to un-hook the harness it would be greatly appreatiated.

http://mahonroy.home.comcast.net/ecu003.jpg

http://mahonroy.home.comcast.net/ecu001.jpg

http://mahonroy.home.comcast.net/ecu002.jpg

Thanks again!
-Matt

i had to wiggle mine until the clip came most all the way out, before the plug would come off... that is all the advice i can give you. i messed with it for a good 30 min or so.

Thanks for the help, I finally figured it out I just wasn't pulling on it hard enough :D Anyways, I had been experimenting with some new displays, to try to bring the cost down as well, though I will still probably make some with the large LCD displays as well. I originally wanted to make this a DIY but it is way too impracticle I think to make instructions like this, maybe I can have a kit or something, I don't know.
I would also like some input from you guys if you dont mind, on what type of features you would like to see in it, etc. What I was thinking was making the screen just out of 4, 7-segment displays (a couple of diff photo's below) to show what the air/fuel ratio is, and possible RPM's, but the point of that would be 1. to keep cost down, and 2. Have it mostly rely on hooking up a computer to it to get information (there is a serial connector on each for serial communication between the device and the chip), and on the software you could log all of your data, and have nice graphs printed etc, and not be limited by the display on the device to view stuff. I could also use leds, led bar graphs, the 4 digit displays, and then like the first one a 2x16 character (5x8 pixels per character) LED display. Anyhow I would like any input on what you guys think, thanks!
Some experimenting with diff displays pics: (sorry for the bad quality of photos)

Working on a 4 digit display
http://mahonroy.home.comcast.net/newp1.jpg

4 digit display connected to computer
http://mahonroy.home.comcast.net/newp2.jpg

checking out led display, and 7 segment display
http://mahonroy.home.comcast.net/newp3.jpg
http://mahonroy.home.comcast.net/newp4.jpg

-Matt

Ok made a new one, has 4 digits and a decimal point:

Pic of design:
http://mahonroy.home.comcast.net/next001.jpg

Close view of 1 of the 4 displays:
http://mahonroy.home.comcast.net/next003.jpg

Now to fit all of that plus the air/fuel ratio and rpm reader circuits into this: :D
http://mahonroy.home.comcast.net/next002.jpg

I was planning on putting this in the area under the dashboard where the speedometer, gas guage, etc. is at, as it wont cover up anything and mount pretty nicely there, what u guys think?

If you make a failsafe that would be uber! start taking orders :D