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Discussion Starter · #1 ·
Hello again,

I have an issue with my 2001.5 Passat that I can't seem to fix. It started with a standard inspection at which point the guys looking it over changed the spark plugs. No big deal. After that though the car started to hesitate and then 'stutter' under boost. After looking under the hood, I found that one of the connectors to the spark plug wasn't pushed down all the way. How could I have not seen that. So, I fixed that and the car drove normally. I came back the next day after the engine had cooled and the connector had pushed back out. Why? As the engine cools the volume of the gas should contract right, creating a vacuum which would definately not push the connector out.

If I push it down right before I drive, there are no problems, but if I don't tend to it then it pushes out and doesn't make the connection necessary to provide the spark to that cylinder. This has caused the MIL light to flash and then become illuminated, indicating a Catalytic converter failure. I understand that if one of the cylinders is not combusting that non-standard exhaust could be causing a probe to read incorrectly or fail.

Sorry for the long post, just trying to fully explain. Any and all input is welcome. Thank you.
 

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Probabaly a loose spark plug. Compression gas is escaping and pushing the ignition coil off. Try retorquing the plug.
 

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Discussion Starter · #3 ·
Okay, I'll try that. Do you think that it will correct the fault code, or are there things I will have to do to correct that? I think I understand that the fault code is linked to the fact that the one cylinder is not firing, and after tightening it, it should fix the problem but is there anything else I should be concerned with (with regard to the cat converter)?

Thanks again for your responses.
 

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Where are you seeing a message about cat converter failure?

The MIL is the same as the check engine light CEL. The fact you saw it means the ECU stored code(s) about the abnormal performance, your likely case cyl misfire. Scan the codes with a OBD-II and you may see a P030x where x is the misfiring cylinder. If the code is a P0420 series then there is slight possibility of cat failure.
 

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When you say "one of the connectors to the spark plugs was not pushed down all the way" what do you mean exactly?

I am assuming that you have individual coil packs for each plug (at least thats the way it is on all 1.8t's I've seen). These coil packs are bolted to the top of the valve cover with an allen head bolt on 2 of the 4 corners- I can't picture how these could "pop off", am I missing something, can you take a pic of what you are talking about?

Here is a crappy picture I found, with coil pack circled in red....
 

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Discussion Starter · #6 ·
first, thank you both for your input.

turtle-thanks for clarifying the code. The Cat failure idea came from the owners manual; I was unaware that the MIL was the same as a general CEL.

riles9b-your're right, on all of the picture that I've seen of the 1.8T I too have always seen that setup in your picture. Oddly enough but standard to my luck, I don't have them. If I did, I understand how it wouldn't make any sense that it would back out.

I will attempt to re-torque the plug. If that doesn't work I would think the next step is to replace them?

Thanks. Your help is much appreciated.
 

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What do you mean you don't have them- you don't have the bolts that hold down the coil pack? Or you don't have a coil pack at all? Now I am curious to find out what your set-up is....

If you do tighten your spark plugs make sure you don't overtighten them!!! I think manual says 22 ft-lbs. for plugs- any more and you run the risk of stripping them out, and that would suck big time. I would really suggest a torque wrench, but if you don't have one, 22 ft-lbs isn't very tight so be careful, its probably not even 1/2 turn past finger tight...
 

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The newer 1.8t does not have bolt down Coil packs. They snap into place onto the plugs, that is all that holds them down.

I believe the last engine with the bolt down Coil packs was either the ATW or AUG circa 2001.
 

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Discussion Starter · #9 ·
Thanks B5BAR,...yeah that's the idea. I have the coil packs, but I do not have the bolts that hold the coil packs in place.
 
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