# Coil pack wiring issue



## dwmaurer86 (Jul 16, 2012)

hey guys, im recently a new 2001 ttq225 owner and have a few questions. first the engine idles rough it- bounces around 1k. I have a downpipe ordered that i plan to install hopefully this weekend because i noticed there was an exhaust leak coming form the flex section on my stock DP. i thought this may be the issue. whil searching on here i noticed talk about the coil packs and when changing the spark plugs i did notice that one brown wire has come unhooked from somewhere near them but all of the coils have a brown wire going to them. any ideas or suggestion as to the possible cause of the idle problem or where that brown wire may go?
Thanks


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## Marcus_Aurelius (Mar 1, 2012)

I just did a coil pack harness swap so the info is still fresh in my head. All brown wires are grounds and are soldered together downstream. Also, on the ignition side of things, make sure your plugs are fresh, gapped properly, and your coilpacks are not failing. You could use the misfire counter in VCDS to make sure you're actually misfiring at idle.

With that said, I'd also look into doing a pressure test to seal possible vacuum/boost leaks that may also be the cause of your symptoms.


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## dwmaurer86 (Jul 16, 2012)

Alright sounds good. I just changed the spark plugs yesterday so I know there good. I plan on trying the vacuum test this weekend. What is the VCDS misfire counter? And I'll make sure I check the coil packs. If I just ground that brown wire to the nearest spot would that work or should I try to track down where it came from? Thanks for the advice. Like I said im new to this and everything helps


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## dwmaurer86 (Jul 16, 2012)

i did check the codes it said that misc cylinder and cylinder 3 was misfiring. i didnt realize VCDS was (VAG-COM Diagnostic System)!!:banghead:


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## Marcus_Aurelius (Mar 1, 2012)

Ok, that narrowed it down. You may have a failing coilpack on cylinder 3 or the harness wires are pretty bad on that particular cyl. To test the coilpack, try swapping it to another cylinder (say cyl #1) and see if the misfire is recorded on cyl #1 in VCDS. That would confirm a failed coilpack (once they start going, it will become a regular thing until you take care of your coilpack harness). As far as the broken ground, I would chase it down and solder it back if the section of wire is not too bad (be ready because you may find some unwanted hidden treasures once you unwrap that harness). :beer:


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## dwmaurer86 (Jul 16, 2012)

alright great thanks for the help im going to try to tackle this and a DP install this weekend.


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## lite1979 (Sep 9, 2005)

Just to clarify, your brown wire should be fastened to the valve cover with a 10mm hex head screw, IIRC. There's one between cylinders 1 & 2 (though closer to 1), and another between 3 & 4. Someone correct me if I'm wrong. I'm guessing you have the AMU motor, which would be the same as mine. I just wrapped the one near 1&2 because it was cracked (in electrical tape for now), and replaced all four coil packs. The idle should be over 1000 when starting from cold, and slowly drop to around 750 once warmed up. Is your idle loping? What are the max/min rpms at idle?


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## dwmaurer86 (Jul 16, 2012)

Well. Installed the DP no luck with the idle issue I'm going to try to tape up the wires for now to see if that helps. It's still loping it fluctuates between I'd say 700 to 800 rpms at idle. It idles fine at a cold start but once it warms up and drops to the 750 range it starts to lope. I changed plugs (NGK)grounded the brown wire. Next I'm going to check the coil packs. It runs fine with no hesitation under power though. Would a MAF cause this?


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## Tommyb13662 (Dec 18, 2019)

*Same wire issue i think.*

Hello, 

You ever find where that wire was supposed to go? It comes out of the loom by itself. my car is a 2001 TT quattro 225 amu. The previous owner did a n249 delete and I was wondering if it was part of that or if it was a ground. I have a black ground near/between coils for one and two. Same lope in idle almost like a missfire but isnt.


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