[V8] 10v issues

[Mark Hanman]

> 3. 10 valve issues (eric anderson)> ------------------------------
Bear in mind that my experience with the audi CIS is related to the WR turbo engine setup.  But the same principals apply.Areas to consider in checking through all of this.
Air sources.  The normal setup will have a completely airtight intake system- air being drawn in via the metering flap only.  So check for cracks and breaks in the crankcase breather system.  These hoses which vent the block, and head, and feed into the intake system will be getting very brittle or perished after all this time.  A leak equals unmetered air being drawn in.
Cold start enrichment.An extra injector which activates for a short period of time, during the cold start sequence.  In K-jet, this is the only electrically fired injector, and operates based on a temp sensing in the head(?) rear,  think.  On turbo cars, the injector is at the back the inlet manifold.  Normal aspirated, I'm not sure.  This sometimes begins to leak, but only a little bit, and often the mixture is adjusted to compensate for this. You will sometimes find these disconnected for this reason.  When a leak is later developed in the crankcase breather hoses, you end up with mixture settings being used to compensate for 2 errors.A combination of these 2 faults can result in some difficult starting issues.
I agree with the chap who says that once the car is running, the check valve should not be an issue.  This will mainly affect starting after a period with the engine stopped, as it will take several second before full pressure is achieved in the system.A good check of the fuel pump is a simple flow check- 900ml in 30seconds being a good benchmark.
www.isham-research.co.ukhttp://www.isham-research.co.uk/quattro/wr_system_pressure.html
has some more indepth info that is compatible across K-Jet cars