Rough Idle and misfire on cold start (2l8v ADY MP9)

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Tottie
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Rough Idle and misfire on cold start (2l8v ADY MP9)

Post by Tottie »

Hi guys,

Please help. Been having this problem for a while and just cant solve it

My car idles very rough (to the point where the dash rattles) on cold start and I can also hear a miss. Small amount of white smoke (can only be seen when looking at the tail pipe) but disappears after about 10sec. This happens every morning and after standing for long periods. The rough idling normally goes away (not 100%) after the car warms up.
I've noticed my number 3 plug being wet (fuel) every time i replace it. The rest of the plugs are all fine just fouled by what i think could be over fueling. I've been basically replacing plugs almost every 2nd month just to get a smooth ride for a while.
I've changed my plug wires, distributor cap and MAF. Problem still not gone.
I've ordered a compression tester and will be testing compression as soon as i receive it. I'm also in process of ordering a head gasket set just to ensure I have it should it need replacing.

Any input on this that you guys might have would be much appreciated.

I'm basically contemplating on buying a new ADY motor if this problem does not go away. But need to motivate the reason to my wife first.

Thanks guys, always appreciate the feedback.
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panic-mechanic
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Re: Rough Idle and misfire on cold start (2l8v ADY MP9)

Post by panic-mechanic »

Ah see it's on Mp9 - have you looked at what the water temp sender is reporting to the box?.
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Tottie
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Re: Rough Idle and misfire on cold start (2l8v ADY MP9)

Post by Tottie »

panic-mechanic wrote: Thu May 10, 2018 12:20 pm Ah see it's on Mp9 - have you looked at what the water temp sender is reporting to the box?.

no i have not. Do you suggest I do diagnostic test first?
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panic-mechanic
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Re: Rough Idle and misfire on cold start (2l8v ADY MP9)

Post by panic-mechanic »

Most definitely. Don't just look for faults - go into measuring blocks and see that the reported cold temp before you start it in the morning roughly agrees to the ambient temp at that stage.
Stephan van Tonder - Jhb - Putfontein Benoni
'05 Audi A6 3.0L TDI Avant
'09 Touareg 3l TDI
'13 VW CC 2l tdi (repair project)
'05 Touareg v10

Perfect Power dealer. I do dyno tuning.
Tottie
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Location: Cape Town

Re: Rough Idle and misfire on cold start (2l8v ADY MP9)

Post by Tottie »

panic-mechanic wrote: Thu May 10, 2018 12:50 pm Most definitely. Don't just look for faults - go into measuring blocks and see that the reported cold temp before you start it in the morning roughly agrees to the ambient temp at that stage.
Thanks, should this test be done with engine cold? Or will it still show the measuring of the cold sending even if its warm? I'm going to take it tomorrow morning for diagnostics. thanks
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panic-mechanic
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Re: Rough Idle and misfire on cold start (2l8v ADY MP9)

Post by panic-mechanic »

Done when cold otherwise meaningless
Stephan van Tonder - Jhb - Putfontein Benoni
'05 Audi A6 3.0L TDI Avant
'09 Touareg 3l TDI
'13 VW CC 2l tdi (repair project)
'05 Touareg v10

Perfect Power dealer. I do dyno tuning.
Tottie
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Posts: 52
Registered for: 10 years 1 month
Location: Cape Town

Re: Rough Idle and misfire on cold start (2l8v ADY MP9)

Post by Tottie »

panic-mechanic wrote: Fri May 11, 2018 11:18 am Done when cold otherwise meaningless
Hi, so i didnt get a chance to take the car for diagnostics. Been very busy. I did however do a compression test.
I first checked all injectors and it was consistent throughout at 14.9 ohm.
I then checked the injector connectors with ignition on and it was consistent at 5.889v
I then proceeded with the compression test.
Cyl 1, 3 & 4 all gives a reading of 215psi
Cyl 2 gives a reading of 195psi. If i do a wet test on cyl 2 it pushes it up to around 213psi.
I bought the car about 7 years ago and the motor was already fitted so i dont know if there was any work done on the car
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