MK5 Golf GTI

All Things Mk5 => How to Guides / Troubleshooting => Topic started by: Vag-mk5 on May 30, 2022, 04:04:51 pm

Title: Mk5 too Rich
Post by: Vag-mk5 on May 30, 2022, 04:04:51 pm
Hello I am from Austria and have the error code p2178/p0172

Fuel Metering System System too rich from idle speed

Bank1

Ne colleague read it with vcds

Up to now some parts have been changed:

 
KGE
ignition coils
spark plugs
injectors
fuel filter
And little things
O2 sensor
mass airflow meter


Do you happen to have any tips on what this could be or maybe someone had an error that could help me :thinking:
Title: Re: Mk5 too Rich
Post by: LC5F on May 30, 2022, 08:35:54 pm
There are a few things it could be:

PCV leak, engine is drawing in extra air, lambda sensor seas the engine running lean so adds more fuel.

Assuming your car is a Gti, it has 2 coolant temperature sensors, one for engine the other for instruments - it could be the engine one is faulty, telling the ECU that its cold pushing more fuel in.
Title: Re: Mk5 too Rich
Post by: Vag-mk5 on May 31, 2022, 01:23:25 am
Hi thanks for your contribution

I'll check the temp sensor


And I recently changed the lambda probe
Title: Re: Mk5 too Rich
Post by: pudding on May 31, 2022, 08:57:53 am
And I recently changed the lambda probe

Genuine or aftermarket?

I've had issues with cheap aftermarket lambda sensors not reading correctly.  The only problem is, genuine ones are around £200 now!
Title: Re: Mk5 too Rich
Post by: Vag-mk5 on May 31, 2022, 09:39:04 am
Yup its from Bosch the old one are bosch

Oriignal cost me 280€
Title: Re: Mk5 too Rich
Post by: rich83 on May 31, 2022, 11:09:07 am
And I recently changed the lambda probe

Genuine or aftermarket?

I've had issues with cheap aftermarket lambda sensors not reading correctly.  The only problem is, genuine ones are around £200 now!

Bosch one is £118 on eurocrapparts
Title: Re: Mk5 too Rich
Post by: pudding on May 31, 2022, 12:34:16 pm
Yup its from Bosch the old one are bosch

Oriignal cost me 280€

If you have an OBD2 scan tool, check the long term fuel trims.  Also check the lambda requested and actual to see if lambda control is actually working.

What is the MAF reading at hot idle?  Should be around 2.5g/s.  Does the MAF number increase when you rev the engine?
Title: Re: Mk5 too Rich
Post by: Vag-mk5 on June 07, 2022, 12:49:09 am
Hi, I have a quick question, can the mixture be changed in my case (rich) due to a leaking Soundpipe(soundgenerator) Or just reduced performance?

Thanks
Title: Re: Mk5 too Rich
Post by: pudding on June 07, 2022, 02:03:35 pm
Possibly.  We didn't get the Sound pipe (thank god!) in the UK so I don't know much about it.

It's normally running too lean these engines suffer from, because of the large number of pipes and connections that can leak.

Running too rich isn't common but you have replaced the common causes of that.  Is the car getting up to temperature? A bad thermostat can cause the engine to run too cool, which can cause over fuelling.

Title: Re: Mk5 too Rich
Post by: Vag-mk5 on June 07, 2022, 04:12:02 pm
Hi, so I found the cause yesterday, the seal from the Soundpipe was not installed I've now dismantled it and stuffed it in there specifically for the hose.

Had an error code mixture too lean immediately after closing it.

I then did a test drive and couldn't find any misfires and the car just jerked more than before.

 But I have to say that I deleted the balance shaft a few years ago.

 Can the error code only come because of the rich run because it ran rich before and now suddenly gets more air.

The GTI has power :thinking:
Title: Re: Mk5 too Rich
Post by: Vag-mk5 on June 10, 2022, 10:57:47 pm
????