Holden astra 96 1.8 takes too many cranks to start when cold

Start w ECM scan, address codes, Check for any cam or crank sensors codes. Check fuel PSI, are the injectors firing? Plug sparking? I know there new but are they working? Scan 1st take it from there. Many emissions sensors (MAF etc can have same effect.) start w scanning

Ihave changed the spark plugs the coil pak and the fuel pump ??????? Before replacing parts did you test the electrical Circuits for the fuel an ignition systems > You don't even know which system the problem is in . Hooking up a fuel pressure gauge an checking pressure and flow , Pulling a plug wire an seeing if there is spark. And it does crank . a crank no start condition . if the starter didn't spin the engine it would be called a no crank no start problem . Your best bet ,take it to a qualified repair shop . That has the diagnostic tool's and knowledge to diagnose the problem ,an not just replace parts . 047 Engine Hard to Start or No Start Scan Data for Ignition

You will need to replace the crank angle/position sensor near the crank pulley. A photo of the sensor is attached. The sensors wear out due to heat and cold cycles and internal corrosion.

MasterPro Ignition - Crankshaft Position Sensor Oreilly's Auto Parts part number is:
Line: MPI ' Part # 2-96054

Is it cranking?.....if it's cranking but not firing you'll need to check things like the fuel pump, (can you here it pumping) other things to check will be coils, spark plugs, leads, relays, crank sensor. If it's not cranking check battery voltage, key remote and immobiliser.

Your engine uses a "waste spark" ignition, meaning it uses one coil for each pair of cylinders. The high voltage current path is to the first spark plug, through the aluminum cylinder head to the secodn spark plug, then out of that plug back to the ingnition coil. One plug fires on the comrpession stroke and the other on the exhaust stroke to ignite any unburned exhaust gasses. The engine's computer "fires one coil at a time based on signals from the crank angle sensor and the cam angle sensor. Likely the problem with your engine is with one of those two sensors.

An OBDII scanner will indicate which sensor is defective. If the engine ran fine before you turned it off, and now it will not start, the problem is likely the crank angle sensor (close tot he crank pully). Otherwsie, oif the engine starts sometimes and not others, it is due to a defective cam angle sensor (near the intake cam "gear" (where the timing belt cover is).

How about the fuel pump...are you getting the fuel to the cylinders? Is the fuel making it through the fuel line through the fuel filter? Drop a few drops in 1 cylinder, if it fires, you have a fuel problem. Does it turn over? If not check out the motor starter!

have you got the timing set correct ,and did you fit the timing belt with all the timing marks lined up ,etc , if there correct ,check for spark ,by pulling off a spark plug lead and fitting an old plug into the lead ,then crank the motor ,dont hold the plug with your hand ,use insulted pliers ,if you have spark, ,if no spark check coil wiring ,coil, crank angle sensor,

pull one spark plug lead off and crank it and see if it has spark if it has no spark it may have a crank angle sensor problem our a coil problem

change the crank censer.