K-Jet FI running too rich?

[aaron at brixtonhill.demon.co.uk (Aaron)]

Hey people

I don't know very much about adjusting fuel injection systems, as will 
become obvious.

MY 8V K-Jetronic roc is running rich (I think), I'm getting run on, 
sometimes for as long as 2-3 secs on shutdown after a run. And my plugs 
looked quite sooty on my last service (but the PO sold me the car in a 
terrible state, so that may not be surprising).

My Haynes (I'm UK, Bentley's are hard to come by), mentions that:

"associated with the fuel accumulator is a pressure regulator which is 
an integral part of the fuel metering device. When the engine is 
switched off, the pressure regulator lets the pressure to the injection 
valves fall rapidly to cut off the fuel flow through them and so 
prevent the engine from 'dieseling' or 'running on'. The valve closes 
at just below the opening pressure of the injector valves and this 
pressure is then maintained by the pressure  accumulator."

How do I test whether this 'pressure regulator' (wherever the hell that 
is) is bad or not?

How do I know whether I'm running rich or not?

If I am running rich, how do I adjust it?

What balance of rich and lean do I want if I'm tuning for performance 
over economy (which is what I'd want)?

Thanks, very, in advance for taking time to answer this

Aaron in London

P.S.

While we're on the subject of my ignorance, how do I pull the head on 
an 8V? Got everything disconnected, except the manifold, how do I get 
the manifold off the downpipe?  - can't see what the hell I'm doing 
back there.

Thanks again...

A

'83 GTi 8V Doner
'85 GTX DD