onrails

I'm surprised they even admitted it was a problem and tore the manifold and heads off to soak and clean the carbon deposits. Not sure if they recommended any measures to keep carbon from building up again. The reason he brought it in was his car would not run smooth when warm, he claimed it was surging, which the tech could not deny. I have had some misses on cold starts, but if i restart the car, the miss goes away. Nothing when the car is warm.

BaysideRS4

Mine sounds like a frigging beast until about 20-30 seconds on a dead cold start. I do have the Milltek non-res, but even with the valves shut at start up it sounds very mean. It also makes sounds that sound like misfires. It definately runs rough at intial start up. But once that cycle is over, it's fine.

I had taken it in for a DTC (no CEL) when I first got it and they ended up putting in different spark plugs. I haven't had any DTCs since.

BaysideRS4

I realize you may be having more issues than what I'm describing. My neighbors M3 does the same thing I'm describing on initial start up.

RI A6

With fuel dilution, fuel replaces the oil that is lost, so many owners will see less oil loss indicated than is actually occuring. Average fuel dilution on these engines is 1.5% to 2%, when the oil is sampled after 20 minute driving cycle. Instantaneous fuel dilution is most likely in the 2.5% to 4% range, but burns off with driving. As the fuel evaporates, it carries some of the volatile oil components with it through the PVC system. It's pretty easy to cycle 1 to 2 quarts of oil through in this amount of time, much of which is probably passing right by the intake valves.

RI A6

Dave, how can that be, if the fuel and additives are hardly seen on the back of the valves?

Nicht ein A4

And a bit of spitting on start up is expected. I agree completely. My car will stall and will hesitate when trying to move (sputtering and not accelerating even gently) unless I let it warm up for several minutes.

It is also a progressive issue that got worse before, was repaired and is now getting worse again. It stalled one night leaving work. I was just sitting there.

cit1991

Open throttles, but limited fuel...helps the cats warm up.

silverRS4

That would probably clean the valves - but I don't think it comes in 5W-40

RVTS4

Perhaps in a 60's muscle car with carbs and manual chokes or even the old one with a bi-metal spring one would expect such things at start, but a modern engine with fuel injection and variable timing all computer controlled, that would be a weak arguement.

ArthurPE

are you saying after only 20 minutes 2% of the crankcase oil volume is gasoline?

after 20 min 2%
after 40 min 2 + 2 x 0.98 ~ 3.96%
after 60 min 3.96 + 2 x 0.96 ~ 5.88%
80 min 5.88 + 2 x 0.94 ~ 7.76%

or simpler (1.00 - 0.02)^3 for oil left after 60 min ~ 0.9412, gas left = 1-0.91412 ~ 0.0588 (5.88%)

so lets say the car travels 3000 miles at an average of 50 mph (pretty typical), that equals ~ 60 hrs or 180 20 minute cycles...

oil left ~ (1.00 - 0.02)^180 ~ 0.0263 or 2.63% oil! eg gas ~ 97%...

isn't 2-3% dilution between oil changes about normal? that would be 1/4 qt...

so as you lose some oil, and gain some gas the level should stay the same...in addition gas is much more volitile than oil, so it's pretty much burned off in the recirc(PVC) system...

if I misunderstood, sorry...