Rough idle when cold

[Sharkie]

Had a rough idle for about 30s the last 2 days first thing in the morning, sounds like a miss? Revving makes it sound normal. After the 30s sounds and goes like normal.

any ideas?

Now that the 9n3s are getting older maybe we need a thread with common issues and fixes?

[s4mmie]

I would venture a guess and say SAI/Combi on the way out. I had the exact same problem. Ripped 'er out and no more problemos

[noone]

yeah, SAI fun.

I'm hoping Guy will find a way to get around the bypass throwing a code on the APR'd Polo's...

[Jmac]

Yeah itll be the SAI combi, and in turn as ive already made a thread about this will eventually fill up with water, a by product of combustion that will make its way to the pump. As with the SAI codes, its fair to say most are having the codes reappear with the exceptions of a couple, the code isnt just being thrown because the ecu is looking for the pump but the 02 sensor also dictates when the sai pump should run, in fact the ecu whilst you are cruising along can ask for the sai pump to run momentarily, thats when most of you will find the MIl lamp coming on and not in the morning when the pump always runs. I know Vwindahouses code hasnt came back and one i did over a year ago has never came back but a couple ive done since have. And this is nothing to do with a tune/flash car as the one i did a year ago is stock as a rock where Anthonys is the polar opposite. The big fix is to remove the bit from the prom table. Untilk then we will have to keep putting the lights out so it doesnt mask a proper reason for the light being on i say proper as we have introduced this one. If we let the light stay on then how will we know if another fault is there?? so thats where im heading with that. I havent doen any of these deletes any differently so it is a funny one that some flag a light and others dont. All have around the same ks so rule that out too.
Cheers
Jmac

[h100vw]

I have had the light come on, on my Polo. I deleted the gear a while back when I first got it home.

I deleted the fault with the original ECU and it seemed happy for 500km or more. Then I swapped in my immo defeated ECU to do some comparison logs, the light came on again. I deleted it just now when I fitted a resistor to the plug.

I'll report back if it comes on again.

Gavin

PS I have a serviceable but noisy Polo pump and the one from my S3 as well.

[Jmac]

I have had the light come on, on my Polo. I deleted the gear a while back when I first got it home.

I deleted the fault with the original ECU and it seemed happy for 500km or more. Then I swapped in my immo defeated ECU to do some comparison logs, the light came on again. I deleted it just now when I fitted a resistor to the plug.

I'll report back if it comes on again.

Gavin

PS I have a serviceable but noisy Polo pump and the one from my S3 as well.

Yeah there is no rhyme or reason Gav, its a flow fault and like i say i can be run during driving anytime really, so not sure why some do and some dont, i guess we have messed with it and all we are doing is fitting resistors for the ecu to think it sees the pump but it then doesnt see its job when reqd, but not them all hmm.
Cheers
Jmac

[h100vw]

I wonder if there's a softcoding change, only tuned 8104 myself but maybe some others have had an update. Also got no resistors on my S3 and the code went away after a couple of resets and has never come back.

Gavin