Let's rewire the ECU!
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Let's rewire the ECU!
Ok, so someone at emanageusers.com replied to my description of the issues I've been having with my eM*. Their suggestion: rewire the ECU power into the ignition power so that everytime I shut off the car, the ECU gets reset without the hassle of the battery removal (genuis, says I)
So how do we do that? I think it would be: cut both wires, splice the wire from the ECU to the wire that goes to the fuse box for the ig, then splice the wire that goes to the harness to the other half of the ignition wire. So the ECU power is now inline of the ignition power (just like the eM itself is inline of the air flow meter signal wires).
Where should I go for the ignition wire? ECU power is the easy one to find (it's the same wire everything else runs off of
Any thoughts?
* the eManage issue, 35 words or less: The ECU is learning around the eManage maps and the only time the eM seems to have control is after an ECU reset. But that only lasts for a little while.
So how do we do that? I think it would be: cut both wires, splice the wire from the ECU to the wire that goes to the fuse box for the ig, then splice the wire that goes to the harness to the other half of the ignition wire. So the ECU power is now inline of the ignition power (just like the eM itself is inline of the air flow meter signal wires).
Where should I go for the ignition wire? ECU power is the easy one to find (it's the same wire everything else runs off of

Any thoughts?
* the eManage issue, 35 words or less: The ECU is learning around the eManage maps and the only time the eM seems to have control is after an ECU reset. But that only lasts for a little while.
Originally Posted by engineerboy
Any thoughts?
* the eManage issue, 35 words or less: The ECU is learning around the eManage maps and the only time the eM seems to have control is after an ECU reset. But that only lasts for a little while.
* the eManage issue, 35 words or less: The ECU is learning around the eManage maps and the only time the eM seems to have control is after an ECU reset. But that only lasts for a little while.
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Switch might be a good idea, too- added security
And yeah, there will be a gradual shift from the eM to ECU during a long trip, but that's not what I'm worried about. I'm concerned that when I autocross, I'm not getting full benefit out of the nearly $2K that I've put into the fuel management/tuning system 
Besides, when you're cruising (throttle below 40% or so), the ECU is in control and keeps the AFR around 14.7 for best gas mileage. I want the ECU to do some stuff, but at the track on on a course *I* want to be in control. The ECU doesn't suddenly take over, it gradually figures out that something's not within its parameters and it adds a little fuel and checks the result. It continues to do this until the primary o2 says the AFR is about 12:1 and timing is where it needs to be.

Besides, when you're cruising (throttle below 40% or so), the ECU is in control and keeps the AFR around 14.7 for best gas mileage. I want the ECU to do some stuff, but at the track on on a course *I* want to be in control. The ECU doesn't suddenly take over, it gradually figures out that something's not within its parameters and it adds a little fuel and checks the result. It continues to do this until the primary o2 says the AFR is about 12:1 and timing is where it needs to be.
Last edited by engineerboy; Jul 4, 2005 at 11:33 AM.
hmmm...is there a way to put a switch like the TV's have....like a toggle switch between your EM to the stock ecu....? might sound stupid, might not be possible...but its just a thought.
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the problem is that the ECU remembers, so a switch like that won't really do much. Besides, I want the eM running all the time, but I want the ECU to control things like idle and cruise functions.
I just tried the switch thing and it worked for a few minutes and now I can't get the car to turn over at all. Oops. Well, I guess it's just one more thing to figure out. Oh, and there are 2 12v power sources. Both need to be tapped in order to keep power away from the ECU.
I just tried the switch thing and it worked for a few minutes and now I can't get the car to turn over at all. Oops. Well, I guess it's just one more thing to figure out. Oh, and there are 2 12v power sources. Both need to be tapped in order to keep power away from the ECU.
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Thanks and I got it to work!! I blew the 20A engine fuse under the hood. Popped in a new one, rewired the switch, taped all the ends and the face of the ECU box so there can be NO shorts and BAM!! Kill switch for added security and ECU resetting without the pesky battery terminal removal.
It's just a 6A metal switch that I spliced inline of both wires 25 and 12 (both of the 12v power wires). I kept the side to the ecu to one terminal on the switch and the other wires on the other terminal, that way the switch can't act as a bypass

Enjoy folks!
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Damnit. The RRE pinout map let me down, or at least the wires I was conecting to the switch didn't do what I needed/wanted. Plus, I'm getting a CEL for "intake air temp sensor high input"
Definitely a bad week to stop sniffing glue....
Gimme a sec. I'm tellin' ya man...AEM forums would probably offer you a lot of general help for the E-manage.
http://forum.aempower.com/bbs/viewtopic.php?t=1279
http://forum.aempower.com/bbs/download.php?id=86
http://forum.aempower.com/bbs/viewtopic.php?t=1279
http://forum.aempower.com/bbs/download.php?id=86
Last edited by HobieKopek; Jul 6, 2005 at 01:02 AM.



