AC knocking engine...??

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CGreen98
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Drives: Polo 1.6 TDI SEL
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AC knocking engine...??

Post by CGreen98 »

So I have a 2011 Polo TDI 90. When I've been driving for a bit (10 minutes+) when I stop the car at traffic or on the drive and take it out of gear the engine shakes/knocks intermittently as though it doesn't know how to idle...

However as soon as soon as I turn on the AC the engine runs completely fine, in fact I get better MPG with the AC on!

Anyone had similar issues with this, I thought maybe it was something to do with the emissions update until I realised it was the AC!


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alexperkins
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Re: AC knocking engine...??

Post by alexperkins »

The reason for that is the AC is putting more load on the engine

You may well have a dirty throttle body so the idle is struggling when there is little to no load on the engine
CGreen98
Getting There!
Posts: 73
Joined: Tue Oct 04, 2016 9:35 pm
Drives: Polo 1.6 TDI SEL
Location: West Sussex

Re: AC knocking engine...??

Post by CGreen98 »

Thanks Alex. That's what I am thinking now... I thought maybe it was the injectors at first. It's booked in at the dealer in a weeks time so will see what they say.


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