Porsche Repair: fuel injection 1.8 litter 1974, porsche 914, mixing valve

Question
Rich smelling exhaust upon start up and rough idle,since this is fuel injected 1.8 litter Porsche 914  there is little or no information on trouble shooting the system.
Is there a fuel air mixing valve that is adjustable or fixed. where is it located.
Car has always been hard to start mostly when hot.
cylinder head tepm gauge has been replace along with other screw in gauges.
any information will be gratly appreciated

Answer
Hi Andy.  This morning I checked for messages and found yours had been duplicated.  So as to remove the second one and avoid it appearing to the All-experts system as if I never responded (the system can't tell its a dupicate)...my response to this first message is that I'm going to go find the answer to your fuel injection problem...and you'll hear from me again shortly.

Dave