Audi 100 Questions

[Kent McLean]

"Ben Doughney" <ben_d at clear.net.nz> wrote:
> When it is cold it won't idle at all, I have to hold my foot on the 
> accelerator for the first couple of minutes. It is also hard to start, 

Cold? Isn't it summer in NZ?   Hard starting may be caused by a bad 
temperature sensor failing to tell the ECU it is cold.  Poor idle may be 
the ISV; clean it or replace it.

> Also, the other day, while I was driving down the motorway, it got hot 
> and started to knock, but hasn't done it since so I am not sure what 
> caused it.

That doesn't sound good.  My guess is that something (blocked
radiator?  Low coolant level? Dead fan?) caused the car to overheat.
The overheating thinned the oil, which couldn't lubricate things 
properly, which caused the knock.

> How do I check the mixture on this engine? 

Use an exhaust gas analyzer?

Kent
'94 100 S Avant
'89 200 TQ, "Bad Puppy" has a new home