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BMW link g4 pnp with audi r8 coils


ThatBoostedE36

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The BMW has built in igniters in the ECU, the stock coils do not have an igniter built in. The Audi R8 coils have an inbuilt igniter. 

To make these work you would need to wire in external pullup resistors and change the spark edge in the ECU.

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Thank you Simon for the reply, The diagram on ecu manual is what I need to follow then? Its says to use 470 ohm resistors but does the watts matter? Ignition x I'm sure its means each individual ignition out from ecu. The little box with the word igniter is each coil i would assume. The last thing is will I be able to use the 5v on the expansion loom for all 6 channels and other sensors being connected to it without stressing it out? I'm sorry for the newbie questions. 

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1 hour ago, ThatBoostedE36 said:

Its says to use 470 ohm resistors but does the watts matter?

1/4W resistor will be fine.  

 

1 hour ago, ThatBoostedE36 said:

Ignition x I'm sure its means each individual ignition out from ecu. The little box with the word igniter is each coil i would assume.

Correct & Correct.

 

1 hour ago, ThatBoostedE36 said:

The last thing is will I be able to use the 5v on the expansion loom for all 6 channels and other sensors being connected to it without stressing it out? I'm sorry for the newbie questions. 

Yep that will be fine.

 

Also make sure you change the spark edge to rising.

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Hello, thank you Adamw for the response, went to go source the resistors with no luck so I ordered them online. They finally came in and went to go install them with no luck on getting the coils to fire. Things I did

Added a resistor on each wire that goes from the ecu ignition output to each coil( i did it right after the ecu plug)

On the other side of each resistor are twisted together crimped go towards the 5v out on expansion loom

Coil pin out:

Pin 1 12v

Pin 2 ground to chassis 

Pin 3 to ecu

Pin 4 ground to head

Ecu spark edge is set to rising 

Coil doesn't even fire on ignition test mode(coils are brand new from ngk)

Edited by ThatBoostedE36
forgot to add another info
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I have moved pin 2 on coil packs from chassis ground to the sensor ground on expansion loom, still no luck.

I don't know if a multimeter can keep up with the output signal on the ignition wire but i believe i measured -0.62 when ecu is not on ignition test mode and switching between 4.77 to 4.89 ignition test mode is on

Also measuring resistance between pin 2(ecu ground)and pin 3(ecu signal) on the coil(unplugged) i got .389 

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I don't know if I'm doing this right but, after trying the 470ohm resistor. I pulled those out and tried a value 10 times less than the pin resistance (389). The closest I got on hand was 10ohm (close to 40 ohms). So after I popped in a 10ohm resistor on just (one) coil, the others were disconnected. On test mode I got the coil to click but no spark came out of the plug(plug was free airing and ground to head). I gave up but then tired to just crank the car with fueling off and I got the coil to fire! 

So after loading up each channel with a 10 ohm resistor then bunching up the other side together and crimping it to a wire that goes to +5v out on expansion loom. I get 5 volt output error code 74 and still don't have spark.

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Yeah thats not going to work.  I=V/R = 5V/10ohm = 0.5A.  So with a 10ohm pull-up each resistor is going to pull 0.5A.  The 5V regulator in the ECU is only capable of about that total and it has to power all the other sensors in the car too.  

Unfortunately, although 99% of coils out there with a built-in ignitor would of worked with this 470ohm pull-up, these VAG coils are a bit of an odd exception so you've got a combo of ECU and coils that were just not designed with each other in mind.

One thing you could try is keep the 470ohm pull-up but connect it to 12V rather than 5V.  The 389ohm coil resistance working against the 470ohm 12V pull up should mean the coil will see about a 5.4V signal.  Pin 54 is 12V.

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On 3/22/2020 at 3:42 AM, Adamw said:

Yeah thats not going to work.  I=V/R = 5V/10ohm = 0.5A.  So with a 10ohm pull-up each resistor is going to pull 0.5A.  The 5V regulator in the ECU is only capable of about that total and it has to power all the other sensors in the car too.  

Unfortunately, although 99% of coils out there with a built-in ignitor would of worked with this 470ohm pull-up, these VAG coils are a bit of an odd exception so you've got a combo of ECU and coils that were just not designed with each other in mind.

One thing you could try is keep the 470ohm pull-up but connect it to 12V rather than 5V.  The 389ohm coil resistance working against the 470ohm 12V pull up should mean the coil will see about a 5.4V signal.  Pin 54 is 12V.

Ok it seems that we got this to work I’m trying to recreate this exact same set up can either you or the other person in this please help me or just simplify what wires go where I really need some help now I’ve got the resistors and the coils and everything I’m just not having success I just need to see or read exactly what wires go where 

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13 hours ago, E36nocap said:

Ok it seems that we got this to work I’m trying to recreate this exact same set up can either you or the other person in this please help me or just simplify what wires go where I really need some help now I’ve got the resistors and the coils and everything I’m just not having success I just need to see or read exactly what wires go where 

The ecu comes with a litte book with a pin out diagram at the ecu

On 7/20/2020 at 3:41 AM, Kyle.36 said:

Any info on wiring into stock ECU?

If u can't change the spark edge and dwell times in ecu then there's no point in wiring them in

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Ok so pin42 is 12v I can send that to the vag coil with a resistor for power as I read above I am just curious as to what I do with the oem harness ground and signal wire since the green one is power I’ll leave that one excluded 

on the vag coils do I connect pin 3 to the oe wire as a signal and then ground it using pin 4 to the brown oe wires or to cylinder head/valve cover 

(currently I have pin 1 connected to the junction box in the bay for 12v like the n54 guys do with the diy they do)  can you help me I’ve gone too far already with this  my Instagram is @e36_sonsa 

image.thumb.jpeg.c2cbaf3133c739d39f9bda52de2adeb6.jpeg

 

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5 hours ago, E36nocap said:

 

Ok so pin42 is 12v I can send that to the vag coil with a resistor for power as I read above I am just curious as to what I do with the oem harness ground and signal wire since the green one is power I’ll leave that one excluded 

on the vag coils do I connect pin 3 to the oe wire as a signal and then ground it using pin 4 to the brown oe wires or to cylinder head/valve cover 

(currently I have pin 1 connected to the junction box in the bay for 12v like the n54 guys do with the diy they do)  can you help me I’ve gone too far already with this  my Instagram is @e36_sonsa 

 

 

Note, unless you have an aftermarket ECU, this will not work.  The output from the factory ECU (which has an ignitor built-in), produces the exact opposite signal of what these coils require.  You will fry the coils in a matter of minutes, and if it does actually run for more than a minute then your ignition timing will give extreme advanace with RPM as your coils will be firing on the dwell edge rather than the spark edge.  

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