Silvia Club of NSW

i changed my oil pump 2-3 weeks ago and while i was there i replaced my timing chain and chain guides, and a new tensioner. i had the battery disconnected for the 2-3 weeks my car won't start up the car was running fine until now

when the ignition is first turned to ON the pump will prime as normal then the sound changes to a pulse which rattles the fuel lines. I can get it to turn over, idle rough, revs will go up and down for a few secs , then stop

i have check all my fuses and my timing is right
the fuel pump is a Walbro i don't know what model
and while starting my speedo was weird showing 180 then it would flash 9 then back 180 then 12 ,180 and so on

any idea's

might of set the cas wrong

nah can't be cas

the idle sounds smooth but it'll pick up and drop 500 rpm up and down for a few secs then stall