off another forum: ICM delete for AEB
01-29-2008, 01:58 PM
#21
Maybe you are referring to other signals, but for the ignition coil specifically, it is as what Jeff
above has posted. How it works is the ECU fires a low voltage signal to turn on a MOSFET. MOSFETs require almost no current to turn on. They only need a voltage potential higher than the source voltage to create a field higher, and "short" the drain to the source. In this case, the source is ground (the 5th wire in the primary side of the ignition modulte). The drain (the 4 outputs of the ICM) is connected to one side of the ignition coil primary. The other side of the coil is connected to +12V (not the ECU).
The built in ICM coils (4 wire coils) just have the MOSFET with the coil. It still takes in the low current signal from the ECU. This approach has been standard on cars even with signal coils.
Now, fuel injectors and the N75 valve on the other hand, have drivers at the ECU.
The built in ICM coils (4 wire coils) just have the MOSFET with the coil. It still takes in the low current signal from the ECU. This approach has been standard on cars even with signal coils.
Now, fuel injectors and the N75 valve on the other hand, have drivers at the ECU.
01-29-2008, 02:03 PM
#22
Interesting you went that approach though. For our TT, I plan to get rid of the factory ignition
coils and use an external driver and some high output ignition coils plus wires. I already tried Nology wires on the stock coils. Can't say much for benefit yet as I will do a dyno with and without them. For our TT, I run 0.034 gap with Iridiums, and over 17psi of KO4 heat I mean boost at 6500 RPM. Hold boost is as high as 24psi when in racing mode, but no misfire issues. Peak is limited to 28psi.
01-29-2008, 02:09 PM
#23
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Re: Maybe you are referring to other signals, but for the ignition coil specifically, it is as what
Perhaps I should post up the schematics for both coil designs.
If you've noticed, the AEB coils simply have 3 pins, while the ATW coils have 4. The difference? There is an extra ground wire, that needs to be SEPARATED to ground the igniter signal from the coil. This would be pin #4 on the ATW coil (which did not exit on the AEB coil).
You cannot simply just create a central and common ground, for it will cause a loopback and premature short of the ECM signal (as you are concerned about).
Here is a brief breakdown of the coil pinouts that I've discovered
AEB:
Pin 1: 12vdc (from ignition/fusebox)
Pin 2: Ground for coil
Pin 3: Input signal from Igniter
ATW:
Pin 1: 12vdc (from ignition/fusebox)
Pin 2: Ground for coil (ATW+ coils also ground themselve with the M6 bolt which the AEB does not)
Pin 3: ECM gated signal
Pin 4: Ground for MOSFET/Igniter
Both grounds for pins 2 and 4 will eventually lead back to the chassis anyways, but this MUST be addressed prior to the swap.
But I do know what you are referring to, as my first mistake during this 2 day project was speculating a single and common ground. Though I did not burn out the ECM, I did experience missfires. The missfires was NOT from a weak or inadequate 12vdc or ground, but rather from the igniter acting up. After addressing this issue, the car ran better than it ever did.
If you've noticed, the AEB coils simply have 3 pins, while the ATW coils have 4. The difference? There is an extra ground wire, that needs to be SEPARATED to ground the igniter signal from the coil. This would be pin #4 on the ATW coil (which did not exit on the AEB coil).
You cannot simply just create a central and common ground, for it will cause a loopback and premature short of the ECM signal (as you are concerned about).
Here is a brief breakdown of the coil pinouts that I've discovered
AEB:
Pin 1: 12vdc (from ignition/fusebox)
Pin 2: Ground for coil
Pin 3: Input signal from Igniter
ATW:
Pin 1: 12vdc (from ignition/fusebox)
Pin 2: Ground for coil (ATW+ coils also ground themselve with the M6 bolt which the AEB does not)
Pin 3: ECM gated signal
Pin 4: Ground for MOSFET/Igniter
Both grounds for pins 2 and 4 will eventually lead back to the chassis anyways, but this MUST be addressed prior to the swap.
But I do know what you are referring to, as my first mistake during this 2 day project was speculating a single and common ground. Though I did not burn out the ECM, I did experience missfires. The missfires was NOT from a weak or inadequate 12vdc or ground, but rather from the igniter acting up. After addressing this issue, the car ran better than it ever did.
01-29-2008, 02:16 PM
#26
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Re: Interesting you went that approach though. For our TT, I plan to get rid of the factory ignitio
Honestly the most efficient spark you will see will be from the L/R coils (AWM). However, you'd also gotta change them like you change oil. ;-)
It's good to finally see someone here with some real background and also shares my thought about Iridium plugs. Some others will swear by Bosch F5DPOR's (with a <0.024 gap) just to keep their ICM's/coils from missfiring. ::high five::
It's good to finally see someone here with some real background and also shares my thought about Iridium plugs. Some others will swear by Bosch F5DPOR's (with a <0.024 gap) just to keep their ICM's/coils from missfiring. ::high five::
01-29-2008, 03:44 PM
#30
since you guys sound lke you know what you're talking about, riddle me this
wtf is this thing off the cp wiring on a 2001 AWM? (a noise reducing capacitor?)
<img src="http://i23.photobucket.com/albums/b373/audiness/what-1.jpg">
see the cp closest to the firewall.
<img src="http://img230.imageshack.us/img230/4792/dscf9631xa9.jpg">
<img src="http://i23.photobucket.com/albums/b373/audiness/what-1.jpg">
see the cp closest to the firewall.
<img src="http://img230.imageshack.us/img230/4792/dscf9631xa9.jpg">