Why does my car pop when dumping boost.

Freeman_1986

Freeman_1986

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As title. Best I can describe it is like a hollow popping noise. Also boost gauge jumps around at the same time (when dumping)

Doing my nut in now.

Thanks
 
You don't have anti lag do you, sounds similar to what you describe, has it been remapped?
 
Not sure on anti lag? What is it? Yes the car is mapped. Was done a few years ago by the previous owner at AMD
 
Freeman_1986 said:
Not sure on anti lag? What is it? Yes the car is mapped. Was done a few years ago by the previous owner at AMD
Click to expand...

AMD don't offer anti-lag on their maps and are generally very anti ... anti-lag.

The basic principle is to ****** ignition on throttle lift,and continue fuelling,so that fuel is burnt in the exhaust and turbo.
The continuing gas flow during throttle closure keeps the turbo spinning,and means that boost is available faster when the throttle is re-opened.

As fuel burns in the exhaust,you get a very obvious banging from the exhaust,and the ignition ****** is very noticeable in terms of how the engine feel,and note change.

That's the raw basics......now that all sounds good,but EGT's go sky high,and extra loads are placed on the turbo shaft,both of which can lead to failure.
 
Won't be anti lag... what rpm and load (part throttle/full throttle etc) is this happening at?

<tuffty/>
 
audi upgrades
F*ck me!!... a red spring?

Put a green in... is it the new design piston with the o-ring seal on the domed face? if not use at least one shim to reduce the piston volume (improves response and peps the spring rate a little)

<tuffty/>
 
Might not be red mind. I'll check when I get home. That's only from memory, as didn't change the spring. Just the piston and o ring.

This was the service kit, which I think is the domed one you're on about
http://pages.ebay.com/link/?nav=item.view&alt=web&id=221523847743&globalID=EBAY-GB

If it isn't the red one, could it be that the spring could be past it and need replacing? Has been on there at least the 2 years I've had it. And seen the receipt for the valve from 2010. So possibly 5 years it's been unchanged
 
Possibly. Serviced it not long ago though, just not the spring. Don't get any error codes, no EML on dash either. Idles fine, it's literally just when dumping the boost. Hopefully it's something as simple (and cheap!!) as just the spring needing to be changed.

I'll check when I get home
 
ImageUploadedByTapatalk1435847588839968


Could this be the problem? Split hose from fuel regulator to manifold.
 
I guess that could lead to over-fuelling on lift off as the vacuum isn't being transferred to the FPR; although I'd assumed that the injectors didn't fire anyway on overrun? Either way it needs fixing
 
Get that sorted asap dude... it will potentially be running lean which is bad...

<tuffty/>
 
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