I found the cause of the ignition coil shorting out
03-24-2006, 06:28 PM
#1
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I found the cause of the ignition coil shorting out
Audi (and VW too!) need to learn how to protect and how to route wires better. This is the third or fourth time I've had an issue with poorly routed/insulated wires in a VAG product. My 1980 Scirocco had even a neat engine compartment fire due to a poorly insulated wire that rubbed through and shorted out. On my A4, the wire that went from the ignition power module to the coils rubbed through and shorted out, causing a coil to fail. That stupid wire is routed through between the intake manifold and the driver side head. it's not exactly cold there and plastic and PVC do get brittle over time. You also can't see most of the wiring. Awesome engineering, Audi!
I recommend that when you have the intake manifold out, you take a close look at all wiring. Look for mechanical wear and tear on insulation.
The wires on the new (used) coils were too short to route through under the IM, and I would not have wanted to put them down there again anyway. The wires are now accessible and can easily be checked for signs of impending mechanical failure.
<img src="http://i4.photobucket.com/albums/y108/moribundman/coil_wire.jpg">
If the image doesn't load, click <a href="http://i4.photobucket.com/albums/y108/moribundman/coil_wire.jpg">here</a>.
The broken wire shows not only obvious signs of being mechanically rubbed through, but also severe oxidation (green patina), meaning this wire's been suffering a slow death over a long time.
PS: Mr.D, thank you very much for supplying a perfectly working set of donor coils!
I recommend that when you have the intake manifold out, you take a close look at all wiring. Look for mechanical wear and tear on insulation.
The wires on the new (used) coils were too short to route through under the IM, and I would not have wanted to put them down there again anyway. The wires are now accessible and can easily be checked for signs of impending mechanical failure.
<img src="http://i4.photobucket.com/albums/y108/moribundman/coil_wire.jpg">
If the image doesn't load, click <a href="http://i4.photobucket.com/albums/y108/moribundman/coil_wire.jpg">here</a>.
The broken wire shows not only obvious signs of being mechanically rubbed through, but also severe oxidation (green patina), meaning this wire's been suffering a slow death over a long time.
PS: Mr.D, thank you very much for supplying a perfectly working set of donor coils!
03-24-2006, 06:51 PM
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I was sweating there for a while
I feared damage to the ECU or the ignition power module. Luckily, my fears turned out to not come true. Thanks again, Michael!
03-25-2006, 02:14 PM
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i noticed that wire when I had my engine torn apart...
it just astounds me that they routed wires in such a hot area... then again, in an engine bay I guess you don't always get a choice 
Was it sitting on the valley pan or against the head or anything? Or just one of "those things"?
glad you got it all figured out buddy!
Was it sitting on the valley pan or against the head or anything? Or just one of "those things"?
glad you got it all figured out buddy!
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03-25-2006, 05:12 PM
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Old and new wire routing
As you can seen, the wires ran previously under the IM, sidling up next to the driver side head. One set of wires (marked blue) went then to the proper (marked white) connector on the firewall, the other set of wires snaked its way above the throttle body and the engine's posterior coolant line all the way to the ignition power module atop the airbox.
<img src="http://i4.photobucket.com/albums/y108/moribundman/wiring.jpg">
Click <a href="http://i4.photobucket.com/albums/y108/moribundman/wiring.jpg"> here </a> if the image won't load.
Thanks to Luxus Panzer for involuntarily letting me ripp off, I mean borrow, his picture for demo purposes. :-P
The set of wires (red dots) that goes to the ignition power module goes now straight from the coils to the airbox. I don't know from what model Mr.D scavanged those coils, but the wires are too short to go any other way -- and that's for the best! The other set of wires (blue dots) goes from the coils along the rigid vaccum tube that goes from the intake manifold to the brake booster and goes straight to the proper connector on the firewall behind the coolant expansion tank. I used zip ties to hold the wires in place, and in a few spots I used thin silicone pieces (blue) (cut from a baking sheet :-) ) to prevent wear.
<img src="http://i4.photobucket.com/albums/y108/moribundman/new_wiring.jpg">
Click <a href="http://i4.photobucket.com/albums/y108/moribundman/new_wiring.jpg">here</a> if the image... you know the drill. ;-)
<img src="http://i4.photobucket.com/albums/y108/moribundman/wiring.jpg">
Click <a href="http://i4.photobucket.com/albums/y108/moribundman/wiring.jpg"> here </a> if the image won't load.
Thanks to Luxus Panzer for involuntarily letting me ripp off, I mean borrow, his picture for demo purposes. :-P
The set of wires (red dots) that goes to the ignition power module goes now straight from the coils to the airbox. I don't know from what model Mr.D scavanged those coils, but the wires are too short to go any other way -- and that's for the best! The other set of wires (blue dots) goes from the coils along the rigid vaccum tube that goes from the intake manifold to the brake booster and goes straight to the proper connector on the firewall behind the coolant expansion tank. I used zip ties to hold the wires in place, and in a few spots I used thin silicone pieces (blue) (cut from a baking sheet :-) ) to prevent wear.
<img src="http://i4.photobucket.com/albums/y108/moribundman/new_wiring.jpg">
Click <a href="http://i4.photobucket.com/albums/y108/moribundman/new_wiring.jpg">here</a> if the image... you know the drill. ;-)