Smelling rich with the odd EPC light

[Geezertronic]

Hi All. I have a 56 plate Audi RS4 Avant which I purchased about 4 months ago. The car has been running fine but when I start it, it does give a powerful smell of petrol which seems to last until the car has warmed up so was wondering whether it was running rich or not?

Also, the EPC light comes on frequently but goes out during the next start - no codes are present when I put a diag tool on it. The only error code I had received (caused the Engline Management light to come on) was a P0491 which a mechanic cleared for me and has not come back.

I understand the only modification done to the car is to have a Milltek exhaust put on it which was done by the last owner (was fitted by Graham Goode in Leicester as per the Invoice recepit). The car runs fine and performance is not impacted when the EPC or Engine lights are on.

Could anyone offer any advice please?

[yorkie]

I'm guessing the EPC will be sticky manifold flaps.

[P_G]

What diagnostic tool are you using on it and if VCDS, what sections are you checking? This may help determine why the EPC light. When you switch your car off and restart is clears the previous code until it happens again up to IIRC a max. 20 times and then triggers the EML light instead.

Could be a number of things, running too rich due to vacuum or solenoid issues but to name just one so a bit more info. would be useful. Does it say the exhaust is cats back or including down pipes race cats? Cat back should pose EPC issues but if downpipes as well could be the lambda sensors have not been replaced properly. Also if the latter exhaust it should have bee remapped but a dealer won't know unless the seller said so which could open up a whole different scenario.

[Geezertronic]

Thanks for the reply. I am not using anything special, just a cheap handheld reader - I've not had anyone run proper diags on it (and I'm not paying dealer prices either). When the EPC light comes on next I'll plug the handheld reader in before I turn it off, and I'll see if my mechanic friends know anyone with a VAG-COM to get some proper info out of it

The exhaust invoice says "Supply and fit Cat Back Milltek exhaust" and contains:

Twin Link Pipe Assembly
RH & LH Non-Resonated Centre sections
Brace Bar
RH & LH Rear Section

Would a remap help do you think or without proper diags is it difficult to suggest anything?

[adsgreen]

I would expect race cats to trip the emissions MIL light not epc but could be wrong.

Codes shouldn't be cleared after a restart - they should be 'pending' even if the light is off but some scanners may not be able to check.

If sticky manifold flaps the code would be Ron related - eg, if the flaps are stuck shut the codes will trip the light as soon as you go over 3k ish rpm.

Proper diags would be helpful