[MarkMac-RS3]

Tuner is on holiday till next week so looking to try and get some guidance in the mean time on my issue.

Sorry for the long post but trying to get as much info surrounding the lead up to the code as possible.

My car was on the rolling road on Thursday and as I’ve suspected for a while it had a pretty crap map on it. Was putting out 385hp and 581Nm. Car was flashed with MRC software but was pulling timing with Shell Nitro, having a suspicion it was a bad batch from a small garage I used, octane booster added to see if it was in fact bad fuel, which it was as the octane booster helped.

Anyway I’ve driven the car about 10 times since getting the new map and at least 4-5 times I’ve got the above code, system too rich off idle. The tank of Shell Nitro and octane was ran down to quarter in the process and filled back up with Momentum. I’ve logged the car and it’s only pulling 1.5 degree of timing from time to time on a 2nd to 3rd gear pull to redline.

The code always seem to trigger around 1700-1800 rpm looking at my VCDS scans. I’m guessing that’s just the specified criteria for it to trigger. Just had a play around and when watching the advance measuring values it seems to misfire when you hold the revs anywhere between 1000 and 2000 rpm. Anything above or below that and no misfires. For the too rich code I started to think injectors but changed the plugs prior to getting the car mapped and cylinders 2-4 had pure white ceramic on the tips and 1 had a very slight black colouration on the ceramic. I know with this map pushing things that but harder than the previous one any issue will be highlighted so I took them out last night again to see if there was anything glaringly obvious but of course the octane booster had given them a brown colour. So cleaned them up and refitted. I’ll check them later for any signs of sooting.

My initial though was maybe it’s the octane booster causing the code but then again it’s not creating a richer AFR just increasing octane and knock suppression. I don’t want to drive the car if I’m risking bore wash with too much fuel going into a cylinder or cylinders.

So on short I’m not sure if it’s maybe just needing a map tweek or pointing towards something else like injectors failing.

[RS777]

Tuner is on holiday till next week so looking to try and get some guidance in the mean time on my issue.

So on short I’m not sure if it’s maybe just needing a map tweek or pointing towards something else like injectors failing.

100% I’d wait to speak to the tuner and see what they are suggesting.

[MarkMac-RS3]

Got in touch today and he said he only sees similar when there is a small boost leak or lambda starting to fail or not switching quick enough.

[MarkMac-RS3]

To me with the intermittent nature of the fault it seems more like the lambda sensor. I would think a leak would be there all the time and rear it’s head all the time triggering the code. I drove nearly 100 miles today before it popped up.

[BenTTU]

So is the sw mrc or some 1 else?

Has this car had injectors?

Boost leak- fault would be under or over boost or malfunction fault for n75.
Lambda can be logged, but tends to throw a fault if it has an issue.

Ben

[MarkMac-RS3]

So is the sw mrc or some 1 else?

Has this car had injectors?

Boost leak- fault would be under or over boost or malfunction fault for n75.
Lambda can be logged, but tends to throw a fault if it has an issue.

Ben

Yeah it’s MRC stage 1 now. I was thinking any of the issues would surely trigger a code of their own.

I’ve logged the lambda and it seems to be working fine. Hovering either side of 1. I’ve yet to log it when the fault triggers though, not that it will make much difference.

I started the car today with the fault present and the car was running very ruff and kept stalling out after 5 seconds, could smell fuel. I’ve started it previously with the code present and it would start ok. Cleared the code and it ran fine again for the cold start and when the revs dropped. Stupidly never logged the car while it was running ruff. I guess it was running rich though or maybe the injectors leaked down I over night and the excess fuel was burnt off the third time o started the car?

Not done injectors on this one but I’m thinking it’s a wise move to do them.

[RS3Dell]

Yeah it’s MRC stage 1 now. I was thinking any of the issues would surely trigger a code of their own.

I’ve logged the lambda and it seems to be working fine. Hovering either side of 1. I’ve yet to log it when the fault triggers though, not that it will make much difference.

I started the car today with the fault present and the car was running very ruff and kept stalling out after 5 seconds, could smell fuel. I’ve started it previously with the code present and it would start ok. Cleared the code and it ran fine again for the cold start and when the revs dropped. Stupidly never logged the car while it was running ruff. I guess it was running rich though or maybe the injectors leaked down I over night and the excess fuel was burnt off the third time o started the car?

Not done injectors on this one but I’m thinking it’s a wise move to do them.

Mark.

Check the engine temperature sensor is not causing an issue.

With a cold engine I would expect to see the water showing round about ambient temperature.

Then watch it while the engine warms up to see any abnormal behaviour till fully hot @ 90'

Dell.

[MarkMac-RS3]

Can’t seem to get the fault to come back now. It kept popping up nearly every other drive. It’s not came back since I started logging the car while driving.

Lambda specified is nearly always 1 and actual value fluctuates either side of 1 as no doubt it should. Manifold pressure specified and actual seem to be within 0.1 Kpa of each other. HP fuel specified and actual track each other very closely as well. Long term fuel trims were around -5.5% last drive and -3.8% the time before. Car doesn’t pull timing much on full throttle pulls, when it does it’s 1.5* up to 2.3* and it seems to be worst around 1000-2500rpm partial throttle I’m seeing up to 4.5* at times. Could well be crap fuel again, I’ll try to fill the tank at another garage and log timing pull, if it’s no good I’ll try octane booster again to see if it helps. Also took the NGK plugs back out and put the stock ones back. I started the car earlier today and got fault codes for multiple cylinder misfire and codes stored for cylinder 2 and 5 specifically.

Car definitely hesitates regardless of what plugs are in it when pulling off just before 1000rpm and quite often at partial throttle in 3rd or 4th till you get past 2000rpm. Lambda actual seems to dip right down to .7 odd when it happens for a split second when I first press the throttle then it recovers.

[MarkMac-RS3]

After a few hours of logging I found what appears to be a link. If I drive in D all the time, no issue. The long term fuel trim is at around -3.1. Short term still goes to -20 and +20 when coming off or on the throttle but it’s a split second and not for extended periods. The rich condition seems to happen when I’m in manual and say at 30mph in 4th and very light on and off throttle when trying to maintain a cruise. I’ve tested at 40mph also in 5th gear, same thing. So it would seem it’s when I’m in manual and in a one gear lower than the car would be in at the same speed and in D.

[MarkMac-RS3]

After looking at the logs I’ve done I took a guesstimate that the an injector/s were actually leaking (more the fact I had checked everything else) The last time I logged the car the long term fuel trim was sitting at -7% even at idle. As soon as I started it would recover slightly and sit around -3 to -4% at best or be away up at -20 to -25% when at partial throttle as before. So it was worse at idle and not so bad at higher rpm when the fuel demand sort of masked the extra fuel from the leaking injector/s. Got some Rev L injectors/ancillaries and manifold gaskets from Audi and replaced the injectors yesterday afternoon and the LTFT is sitting around +/- 0.8% for the most part now.