Hello all, question about a rebuilt 07 rs4 motor

B6/7 S4/RS4
#1

First off I’d like to say hello, I am new to this forum and was directed over here by a member of audiworld. Maybe you all could help me out with a small problem I’m having…

So I just got my 07 rs4 back from the dealership today, they broke the whole engine down, new piston rings, full carbon clean. Installed my JHM lightweight flywheel, stg 3 clutch, Intake Spacers and LW Crank pulley. A few questions regarding how the engine should run.

Since I am still breaking everything in I have been “taking it easy” on her, still pushing it hard but not to redline. When I am driving along at a constant speed every 30 seconds- 1 minute I feel almost like the power cuts out for half a second. Enough to where the momentum will make your head bob forward ever so slightly and the RPMS drop. Has anyone ever herd of this. My tech was saying it could be a combo of the LW pulley and LW flywheel that is making that happen but I’d like to think differently since the clutch is engaged and there is forward movement.

Also, the car is having trouble staying idle… it will never stall itself out but if I just let it sit there idling for 2 minutes the rpms will drop to the point where you think its going to stall then you here the big woosh and the engine rev up past 1100 and drop back to normal. This will go on and on.

Any thoughts? Could it be bad gas? The dealer filled it up at their pump which was not labeled with any octane rating… I have no idea, I’m stumped.

She defiantly pulls like a SOB now, that magic 5000+ RPM zone is heavenly now, can’t wait for everything to be broken in. Also, if you drive it hard none of those symptoms are present… only if you are following a car an remain at a constant speed, in 2nd gear it happens around 2700-3k…

Any thoughts, chime in.

#2

great for you to have the new motor. The iddle might have something to do with the (as I understand) power drop.

A LW flywheel will allow the motor to rev faster up and down in the rpms but it won’t create a drop in power when your foot is on the throttle. So that might be more VAC leak or something related to that.

Start with vac leaks. The iddle thing gives you the idea there is something wrong there. Also this might be just the motor getting too high load during the break in prosses. I still however think its going to be a vac leak. Your car shouldn’t be doing that at iddle.

#3

Here is a short video of it idling… 18-19 second mark is when it starts to die out…

http://youtu.be/M-y016OdLIM

also it is at the dealer now and they found some leaks, brake booster and some other one…

#4

haha tech points for me. YAAAA

That should help sort out most of what your having happen.

#5

well done Hyden

hope it works out sub

#6

My car has had the idle drop and rev up before and after the new motor. A tech once told me the reason and I think it had something to do with a certain cycle the ECU goes through. Shit, I wish I could recall exactly what he said.

I know exactly what you are referring to with the hesitation while at a constant low rpm, it’s like a hic-up and then it recovers. This was also explained to me way back when I first got the car, had to do with the stock calibration…interestingly enough, it did it with the JHM tune I had also…and I’m back to stock calibration with a stock tune and it still does it.

BTW - I know of at least 10 - 15 RS4 owners who also experience BOTH of these exact issues. There were threads related to both of these items and the number of responses sharing the same experiences was large. Stock and modified cars alike.

#7

it sounds like anti-stall kicks in to save the rev

#8

When I did the carbon cleaning on a friends 07 S6, it was idling exactly like that when I was done. Went in VAG-COM and hit “clear codes” for both ECU’s and it instantly stabilized the rpm’s.

#9

I have experienced this a little bit too, not quite that dramatic, but I have seen a little change in power at a constant speed. I remember JHM’s tuner said that the car goes through a self-test procedure on the fuel pumps every so often, not sure if this could be related to it. I know I have seen a little of it even with the new motor and new fuel pumps, so it should eliminate those two failing as causes.