What do you think this could be?

[APL TDi]

Hi all

I have a 2004 A3 TDi 140. Had a new turbo put on it last week. Everything seemed fine for the first week, but then it developed a stuttering under hard acceleration.

It is fine up to 3,000 rpm but then it stutters and coughs and loses and gains power.

What do you think this could be?

I ahve posted a simlar question in the A3 8P section, but was hoping for some diesel expert advice.

Cheers

A!

 

[APL TDi]

The car seemed fine this morning, no hesitation and accelerated hard through the rev range.........

I am now very confused

 

[evomaster3000]

MAF problem? turbo's take a while to spool up and drop power so it probabily wouldn't be the actuator or vacuum supply to it.
could be a leaking egr? or bad egr vacuum supply/fault dumping the boost irratically.

 

[fjtwelve]

Agree MAF is a definite suspect. Next time you have the problem unplug the MAF and see if it gets worse. If it doesn't then the MAF is probably knackered. Unfortunately MAFs fail gradually sometimes, drives you mad. Stuttering is possibly due to fuel starvation or flooding, turbos and valves don't respond fast enough to cause a stutter. Maybe you cleared a blockage in the fuel lines, could be the fuel pump and its ecu playing up. VAGCOM check is a good place to start. Find an independent specialist. Where are you?

 

[APL TDi]

Cheers guys.

I am taking it back to the dealer this evening and they are puttting it into audi tomorrow so they should be able to do a diag check.

As said its fine now, so hopefully it was just something bedding in or snagging in the fuel or boost system.

Audi are going to have a look at the turbo to make sure nothing is loose causing a boost leak, hopefully it will be fine (touch wood)

 

[spud28]

well done, Have you fired it up yet?

I should have done my head gasket myself but instead I thought I would get a replacement engine from a breakers. The problem is instead of a replacement AFN they've sent a AHU and won't give me a full refund as they say it's the same engine with a different exhaust gasket and turbo and all I need to do is swap my ones over.

I have had differing opinions as to whether or not this is the case. Could you enlighten me? or direct me towards someone who could help, please.



Cheers, Spud28

 

[etronic]

well done, Have you fired it up yet?

I should have done my head gasket myself but instead I thought I would get a replacement engine from a breakers. The problem is instead of a replacement AFN they've sent a AHU and won't give me a full refund as they say it's the same engine with a different exhaust gasket and turbo and all I need to do is swap my ones over.

I have had differing opinions as to whether or not this is the case. Could you enlighten me? or direct me towards someone who could help, please.



Cheers, Spud28

I don't know how this post refers to the topic but i can tell you that these two engines are completely different
AFN is a 110BHP witn VTG turbo and AHU has only 90BHP and turbo with no variable nozzle geomerty. Also AFN got DMF while AHU not.