My 1992 JA classic has always been temperemental cold starting. Its always OK if you turn over and then give some throttle as it just picks up and you keep it reving then slowly drop down 550 RPM.It will not idle properly for about 1.5 mins until the Ecu brings up the revs from 550 to 1000 Rpm ? ?. Sometimes I get it wrong and it dies , it will not re-start and often I have had to tow start it, the plugs are wet.Removing and cleaning the plugs does not help much. The spark and timing are good and fresh petrol . I always start on petrol warm up before changing to gas
I have fited a new Idle valve, Coolant sensor and battery.No vacuum leaks. The idle valve does not seem to be fully open on starting , its about 4mm open is this normal?.Could the throttle potentiomer , throttle flap flowmeter be causing the problem

Have you done a search? There are lots of threads to do with poor starting and idle issues, use the search function and look for poor idle or starting problems. Happy reading.

also were they gen parts you fitted?

Strip and clean all the breathers, basically overhaul everything on the top end to amen sure its all clean and good as new.

The engines depend on a metered amount of air. Any issues/leaks/blockages give trouble.

Should be an easy one

Nice bright white spark? Or yellowish spark?

It would not start yesterday ,left it overnight and got the garage a bit warm and it started first time . The slow running after 2 mins came up after I droped the revs to 500rpm and then the ECU/ valve brought the revs up to 1100
Its an original temp sensor but no manufacture mark on the idle valve.The spark is yellowish on the colourtune running on petrol maybe its too rich. I normally run on LPG so the gap is .032 Bosch WR9DC plugs . Crank case breather is clean, are there any others ? I will clean the thottle flap etc. has anyone experienced this problem . I have read that it is possible to operate the idle valve by repeatably swiching the ignition to position 2. I have tried but it doesnt seem to move.I dont think the 1992 RRC 3.9 Lucas hotwire injection has a cold start injector?.Appreciate any suggestions .I can put with most things but its got relliably start

yeah no cold start injector on the hotwire motors

It is the temp sensor giving you over rich.