2002 VW Passat 2.0L 130bhp AZM Engine (petrol), Cylinder 3 Misfire, out of ideas

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Sun 1 Jul 2012 13:49
2002 VW Passat 2.0L 130bhp AZM Engine (petrol), Cylinder 3 Misfire, out of ideas - paul1972uk
Any help greatly welcomed.

I have a 2002 2.0L petrol (130bhp AZM Engine), with single DIS Ignition coil pack. The engine warning light came on with a misfire whilst doing 40mph (no previous warning or indications of potential problems), which is present at all engine speeds. I had the code read, indicating a misfire on cylinder three. I have completed the following checks and run out of ideas:

1) Cleared the codes and restarted engine.
2) Replaced the spark plugs with new ones.
3) Old spark plugs were in good condition with no oil, no deposits and the electrodes in good condition.
4) Checked HT lead condition and found no corrosion, a tight fitting cap and no damage to cable.
5) Earthed the HT lead and have strong spark when engine turns over.
6) Checked the injector electrical connections with a bulb tester and all is fine.
7) Removed the fuel rail and extracted cylinder 3 injector.
8) Performed a visual inspection of injector with all looking good and no blockages at the jets.
9) Tested the injector on the bench using a 12V battery to ensure it opens and closes correctly.
10) Replaced the injector in the rail and turned the engine over to check for blockages, with all injectors operating.
11) Swapped cylinder 3 and 4 injectors (misfire still on cylinder 3, no change)
12) Inspected fuel and air connections and ensured no leaks.
13) Checked the engine oil condition with no evidence of water contamination (head gasket)

Any ideas would be most welcome

Edited by paul1972uk on 01/07/2012 at 13:50

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Sun 1 Jul 2012 16:00
2002 VW Passat 2.0L 130bhp AZM Engine (petrol), Cylinder 3 Misfire, out of ideas - unthrottled

Does it feel like the engine is misfiring?

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Sun 1 Jul 2012 18:34
2002 VW Passat 2.0L 130bhp AZM Engine (petrol), Cylinder 3 Misfire, out of ideas - Peter D
Do a compression check to ensure they are balanced. Regards Peter
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Sun 1 Jul 2012 19:00
2002 VW Passat 2.0L 130bhp AZM Engine (petrol), Cylinder 3 Misfire, out of ideas - madf

The HT lead may break down under load. Cheap to replace..

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Wed 4 Jul 2012 15:19
2002 VW Passat 2.0L 130bhp AZM Engine (petrol), Cylinder 3 Misfire, out of ideas - paul1972uk

Found it.... Split breather pipe under inlet manifold

Thanks for the input everybody

Edited by paul1972uk on 04/07/2012 at 15:20

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