Mk 5 GTI - lumpy idle and P0171 error code.

OSI · 26-08-2013 8:25pm #1

So for the last week I've noticed a rather lumpy idle in my GTI. Especial when the engine is warm.

It started out rev hunting between 800 and 1500 rpm. Rising slowly, sitting at 1500, then falling back slowly. More recently it's started to splutter after falling back down. So I imagine it's trying to figure out an AFR.

On Saturday, the CEL came on, and a quick scan with Torque pulled up the code P0171, System too lean. Which again points to an AFR problem. I figured it was a vacuum leak, or bust PCV, but I've checked and can't find any evidence of either.

Any other suggestions? If not, any suggestions for a good VW Indy in north Dublin? Would love to bring it to George, but it's a bit far for what I hope is a simple fix.

George Dalton · 26-08-2013 8:42pm

It is probably the PCV to be honest. Did you take the old one off for a look?

George Dalton · 26-08-2013 8:47pm

Does it have all of its power? Do you think it is making full boost?

George Dalton · 26-08-2013 8:52pm

If it is down on power then you are looking at a possible turbo diverter valve failure then. The original diaphragm type valve gave lots of trouble, the current version is an improved piston type.

George Dalton · 26-08-2013 8:56pm

It can affect the idle alright. If you can take it off yourself then it is definitely worth doing, it will be really easy to see if it is torn once you have it off.

Killinator · 28-08-2013 8:53pm

OSI wrote: »

Hmmmm, new code. P0441 - Evaporative Emission Control System Incorrect Purge Flow

Hopefully I'll be able to get under this weekend to have a look at that DV.

I have that, it comes and goes

Killinator · 01-09-2013 1:52am

OSI wrote: »

Got this sorted today. Got the DV and breather pipe replaced by a local mechanic after I ordered the bits online. Car is back to it's best and I have my boost back.

So much giggling and smiling on the drive about after.

George, you're a legend! Name your brew and there'll be a case on it's way to ya.

Can I ask where you sourced the necessary part(s)?

tossy · 01-09-2013 11:17am

Did you uprate or did you order OEM parts from ECS?

Neilw · 01-09-2013 11:42am

tossy wrote: »

Did you uprate or did you order OEM parts from ECS?

Anytime I looked at stuff from ECS the shipping cost put me off.

tossy · 01-09-2013 11:44am

Neilw wrote: »

Anytime I looked at stuff from ECS the shipping cost put me off.

I agree,i only ordered from them once and that was only becasue the Brake kit was a good deal and the dollar was weak at the time.

Mk 5 GTI - lumpy idle and P0171 error code.

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