[Ryans24]

Hey everyone I have a problem with my plugs keep getting sooted up I had a code for running rich p0172 so I've replaced fuel filter plugs all injectors fuel pressure sensor and hpfp and it still does it has anyone else had this

[RS777]

This is what I found for possible causes on a A3, including RS3 models . Hope this helps.

Vacuum Leaks– With the Audi A3, one of the most common cause for the P0172 code to show is a vacuum leak. Take a look around and see if you can find the vacuum leak.


Oxygen Sensor– The P0172 codes is thrown when the oxygen sensor(s) do not register the right amount of oxygen in the exhaust. When the oxygen sensor is bad, it can cause a false reading and trigger the code. The computer will still adjust the air/fuel mixture to compensate. This will cause the A3 to run rich. Audi A3 O2 Sensor
Mass Air Flow Sensor– The mass air flow sensor calculates the volume of air entering the engine. If it has gone bad, the air fuel mixture will be off and the P0172 code will show.
Bad Fuel Injectors– If you have one or more fuel injectors that have gone bad that can certainly cause the air/fuel mixture to go bad.


Fuel Pump/Fuel Filter– Today’s modern fuel injected motors need a lot of fuel pressure to atomize the gas properly. If the fuel pressure is off, atomization doesn’t happen properly and the optimal air/fuel mixture isn’t achieved.
Air Filter– While it’s not the most common reason to throw the P0172 code, a clogged air filter certainly can cause the code to throw. And, since it’s so easy to check, why not look?

[Ryans24]

I've checked the air filter it seems to be in OK condition so that rules that out I've also changed the hpfp and injectors so that rules them out so that leaves vacuum leak or o2 sensor it's also got map sensor instead of maf so it couldn't be the maf sensor

[RS3Dell]

Ryan.

What RS3 do you own mate ? The 1st O2 sensor will control your fuel mixture as it's of the wideband variety.

Dell.

[Ryans24]

It's a 8p mate and I did think it could have been that to be honest

[RS3Dell]

It's a 8p mate and I did think it could have been that to be honest

Ryan.

The 8Ps are 10 years old now so things will start to going wrong, mine's in need of the DMF replacing & a slight oil leak at the back of the cylinder head.

Dell.

[Ryans24]

Tell me about it I've just had the chains and dmf replaced along with all my fuel related stuff

[RS3Dell]

Ryan.

I replaced my injectors with the "L" spec one's a few years back,had the HPF sensor play about once so I changed that,the fan motor module also failed.I did all the work myself so it took some of the sting out of it

Dell.

[RS777]

Ryan.

I replaced my injectors with the "L" spec one's a few years back,had the HPF sensor play about once so I changed that,the fan motor module also failed.I did all the work myself so it took some of the sting out of it

Dell.

Would FL port injectors fit an 8P Dell?

[RS3Dell]

Would FL port injectors fit an 8P Dell?

Stu.

I believe the port injectors are only used at low rpms on the FL to help solve the issue with carbon build up on the back of the inlet valves so I would have thought they wouldn't be of any use in the earlier engines as a direct replacement even if they were to fit.🤔

Dell.

[RS777]

Stu.

I believe the port injectors are only used at low rpms on the FL to help solve the issue with carbon build up on the back of the inlet valves so I would have thought they wouldn't be of any use in the earlier engines as a direct replacement even if they were to fit.

Dell.

Fair enough, just a thought as I have a spare set.