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Old 01-24-2010, 07:38 PM   #1
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Default Wideband location and other issues.

I have a few questions about the new to me Miata.

1. This car has the AEM wideband installed under the car in the test pipe location. Is this ok? Seems like a long way away from the engine, but perhaps that is not a problem.

2. How important are ground and power locations. I'm assuming that the power needs to be connected to the MS lead and the ground to the ECU ground in the engine bay near the throttle body. I'm assuming this could cause mis-matched AFR numbers.

3. The test pipe is 2.25 with crush bends in it. I am assuming that this thing needs to be replaced with 3 inch ASAP? The rest of the exhaust is 2.5 inch Enthusa with a Magnaflow muffler. Down pipe is a 3 inch that has some "clearancing" done around the steering shaft. I was thinking about an electric cutout for track purposes. Do these work and stay working?

I'm sure I'll have more.
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Old 01-24-2010, 07:53 PM   #2
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I want to point out that every time you activate that exhaust cutout, you'll want to be on a different tune than when running through the muffler. Probably fine for a dedicated track day, but not so realistic if you're into roaring off at a green light.

That being said, I have no personal experience with cutouts, so this really is just noob forum surfing experience talking.

EDIT: That's right--I do remember having to deal with a going lean situation when I uncorked the exhaust on an old speed density based EFI setup years back. I take back the noob surfing statement on this one.
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Old 01-24-2010, 08:17 PM   #3
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Just do a proper 3", there isn't much to be gained after that.

There are a million threads on the GND problems. Read the directions to a "T" and do not variate from them. You will probably stack the grounds because everyone seems to think you can, then you will fail and we'll send you the links.
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Old 01-24-2010, 09:14 PM   #4
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Just do a proper 3", there isn't much to be gained after that.

There are a million threads on the GND problems. Read the directions to a "T" and do not variate from them. You will probably stack the grounds because everyone seems to think you can, then you will fail and we'll send you the links.
HAHA OK! I'll get to that when I get it in the heated garage. I'm thinking the TPS may not be correctly calibrated either. It goes from 9-70 in the datalogs. Is that normal?

So you think the 3 inch test pipe to the 2.5 inch exhaust will be fine. Sounds easy. Or are you saying "proper" as in 3 inch all the way out the back.

Is the location of the wideband ok? Should it be moved closer to the engine?

Sorry for the questions, but if I had built and tuned the car initially I probably wouldn't have these questions. I'm working on loosing my status so I can help others some.
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Old 01-25-2010, 06:39 PM   #5
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Is the location of the wideband ok? Should it be moved closer to the engine?
Per this thread, it should be in the downpipe and at least 18" from the turbo.
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Old 01-25-2010, 07:18 PM   #6
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Quote:
Originally Posted by rweatherford View Post
I'm thinking the TPS may not be correctly calibrated either. It goes from 9-70 in the datalogs. Is that normal?
Tools -> Calibrate TPS
Click the respective "get current" buttons with zero and then full throttle. That's it.
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Old 01-25-2010, 07:40 PM   #7
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On mine the sensor was installed right there on the firewall at 90 degrees.

All the wires were ground to the engine (separate from one another), works like a charm, note... mine is a Innovate wideband.
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Old 01-26-2010, 12:24 AM   #8
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Thanks guys I'll do some reading, get my AEM moved and regrounded, work on TPS and go from there. If I get all that straightened out I can try installing the EBC with MS control.

Last edited by rweatherford; 01-26-2010 at 01:14 AM.
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Old 01-26-2010, 12:11 PM   #9
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I used my radio's power and ground on my innovate wideband. AFR's seem about right for what a stock ecu will do.
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Old 01-26-2010, 12:53 PM   #10
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The sensor is self heating, so it can go pretty much anywhere. The key thing is not to get it *too* hot, that screws it up. That's why the recommendation to keep it at least 18" downstream.
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Old 01-26-2010, 08:15 PM   #11
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I knew it was self heated. Didn't know if the distance screws up reading the log files and tuning. Perhaps I'll leave it where it is and check for voltage differences between grounds and power locations. Could just wire them together on the ground side. Probably can't tie the power locations together without causing problems, even with fuses on each end. I'll have to review the instructions thoroughly.
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