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Old 08-20-2008, 09:19 PM   #541 (permalink)
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I've got an AEM EMS in the car for the engine computer. I found that the original vss was a reed switch in the speedometer head and that the EMS did not like the signal from the first gen Mitsubishi. They say the second gen cars don't exhibit the problem. Several years ago I added an aftermarket hall effect in-line speed sensor that it mounted directly on the transmission and then the original speedometer cable is screwed to the top of it. My understanding of the speed signal was 4 pulses per rotation of the speedo cable. I have never found what that was supposed to be per mile. When I got the speed sensor from the Speedo shop, they said it should match so I fed the output of it to the EMS and it was the same as the original except that it was very stable and didn't flucuate like the original reed signal did. Earlier this year the speedometer got to wiggling and the cruise wouldn't stay engaged for more than a few feet, replaced the cable and it worked fine. The EMS vss reading was still stable and didn't flucuate, course the sensor for it is before the cable. This is the sensor that I attached the to the MPGuinio.

When I tried the MPGuinio on the reed sensor wire that had originally gone to the factory ecm, I didn't get any reading at all. So I just hooked it to the aftermarket one feeding the EMS because the pulse count should be the same as stock. I'm wondering if the flucuation I'm seeing is simply that I've probably put 35-40 thousand miles on it since I put this sensor on it and it now has some wear in the bushings allowing it to wiggle?
The EMS still shows steady speed up and down but maybe it isn't reading + to + pulse but just + or - and that is how it determines speed.

Can you think of a way I can get you a good picture of the scope screen to make a determination from? I don't think this one will let me save it in a manner that I could download the trace and send it out.

Mark

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Old 08-21-2008, 12:49 PM   #542 (permalink)
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Hey all, Added an enclosure section to the Wiki!!!

Check it out!!

MPGuino - EcoModder

You can all thank WagonMan76 and DriveByNothing for the design and Pics

Last edited by TruckTrash; 08-21-2008 at 01:24 PM..
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Old 08-21-2008, 03:03 PM   #543 (permalink)
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Originally Posted by TruckTrash View Post
Hey all, Added an enclosure section to the Wiki!!!

Check it out!!

MPGuino - EcoModder

You can all thank WagonMan76 and DriveByNothing for the design and Pics
Sweet, I'm coyping DBN's case design (same 4x2x1 case and inputs / 7805 sticking out the back). I'll have pics soon. Currently I've got my iDuino built, my LCD has its ribbon set up, my iDuino shield is mostly configured, just need to add the jumpers from the iDuino pin connectors to the header for the LCD, and add buttons somewhere. It's coming along quite nicely and modularly!
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Old 08-21-2008, 06:13 PM   #544 (permalink)
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The wiki looks great! Glad you guys like the enclosure.
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Old 08-22-2008, 12:44 PM   #545 (permalink)
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Just finally got my "production" 'guino built! Noticing one little thing with v0.70... Tested with 0.67 to compare and with v0.70, when sitting on the bench unconnected, Speed shows as 294967, and in instant Data, uS is showing garbage data too. Is this just a side effect of the new interrupt system that will go away when hooked up? I won't have a chance to run power wiring in the car until tonight or tomorrow.
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Old 08-22-2008, 01:06 PM   #546 (permalink)
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Dont know about uS, that speed thing on the front page threw me off too. But once connected properly in the car, the speed goes to zero once the mpguino starts getting fuel pulses.
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Old 08-22-2008, 01:17 PM   #547 (permalink)
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Good that's what I wanted to hear. Wanted to be sure I didn't make a mistake with the wiring. Well, I should say "another mistake", because I accidentally swapped two wires when building my iDuino shield. So I did what any good hardware engineer would do. I fixed it in software. Just a simple RS and Enable pin swap, so 4=5, 5=4, done. Just got to remember to keep making this mod in code for future updates...
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Old 08-23-2008, 01:36 PM   #548 (permalink)
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Well I think I got my display all figured out. I found that if I disconnect the ground wire from the display, it will still run fine but it kills the backlight. It pulses just a little with the blinking light on the Arduino board but its not a big deal . So put the wire normally to pin 15 of the display to an NPN transistor that breaks the ground to the display. The different levels of brightness now work too.

I was kinda hoping I could kill the display entirely, but if I do that, it shows jibberish when it comes back on unless it is reset. So anyway, I think I got it working as intended. It does time out properly now and hopefully the killing of the backlight will make the screen less hot when not in use.

The display I used was from ebay, item# 320277596129. They say yellow-green backlight with black characters. It is actually a green backlight with blue characters, which still looks nice and is easy on the eyes. It looks just like the display on the old Casio graphing calculators.
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Old 08-24-2008, 05:58 PM   #549 (permalink)
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For editing of the variables, I personally would rather whip through the screens with one click each till I get to the one I need, then whip through the rest to get out. It makes going in to edit one variable a lot faster, without fear of screwing up the rest. So in the EditParm section near the end of the code, I changed the following in mine.

From this:
Quote:
byte p=9; //right end of 10 digit number
To this:
Quote:
byte p=11; //XX
And I removed this section:
Quote:
for(int x=9 ; x>=0 ;x--){ //do a nice thing and put the cursor at the first non zero number
if(fmtv[x] != '0')
p=x;
}
Just my preference. I tried it and it does work so if anyone wants to use it, feel free.
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Last edited by wagonman76; 08-24-2008 at 06:09 PM..
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Old 08-28-2008, 02:51 PM   #550 (permalink)
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MPGuino complete! Now w/ 100% more pictures!

I'll add these to the enclosures section of the Wiki in a few...






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