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At 4000 rpm ?
Posted: Sun Jul 05, 2009 5:36 pm
by BobC
I have just test driven a very nice S4 Avant which I am considering buying but I have one reservation.
At 4000 rpm on an open throttle there is a very noticeable clunk or bump from the engine. Worse in 2nd and 3rd gear.
Does anyone have any ideas what it could be? I have asked the seller to have it checked out before we talk money.
Thanks.
RE: At 4000 rpm ?
Posted: Sun Jul 05, 2009 7:31 pm
by Sql_RS4
Maybe engine mounts on the way out?
RE: At 4000 rpm ?
Posted: Sun Jul 05, 2009 9:21 pm
by BobC
It happens at the same rpm in every gear gear, just more severe in the lower gears. I was trying to find out just what happens mechanically at 4000rpm. Such as cam timing changing or something to do with boost. Any ideas welcome. This car has been chipped, I assume it's not normal for an S4 to do this.
I just noticed this problem was raised back in April, thought to be plugs or coil packs. Was it proven at all ?
Posted: Thu Jul 09, 2009 6:26 pm
by BobC
Ok, for the record I found the problem.
It was the Y shaped pipe on the throttle body. There was a split which would remain closed until 4000 rpm when there was sufficient boost pressure to open it. Just like a dump valve.
The car goes like it should now.
Posted: Thu Jul 09, 2009 10:11 pm
by Blue_Thunder
It's metal on the RS4 though!
Posted: Thu Jul 09, 2009 10:44 pm
by TopBear
Blue_Thunder wrote:It's metal on the RS4 though!
Looks like its been posted in the wrong forum
BobC wrote:I have just test driven a very nice S4 Avant