hard to start

hi after some help ,the past month my g13bb engined jimny started to play up . after standing all day or over night it has become hard to start, turns over well but takes loads of turning over coughs into life if you lucky. once running it does not miss a beat.i changed the spark plugs but it is just the same . once it is running you can stop it and starts immediately . i can hear fuel pump prime when ignition is turned every time . could it be the cam shaft sensor ? i would think it would play up when running if it was .

any ideas would be gratefully recieved .thanks

Fuel pressure could be a problem, voltage also. How fresh is your battery? A poor spark can cause problems. Could be a problem with a temp sensor as well, not allowing the ecu to compensate for the cold start. So many possibilities. I use a BluePoint MicroScan tool through the OBD port to check info in realtime as this can flag up issues.

Thanks for the reply. The battery was flat as a pan cake a bit back as the lights were left on all day. And that might be it as once its running it does not miss a beat. I will give it a good charge see if it starts in the morning. How much is that diagnostic tool and best place to buy it from. Cheers

It's a snap-on item and not cheap, I'm sure there is a thread on here about cheap OBD scanners somewhere. To test the theory hook up a pair of jump leads from another car when you start it from cold. If it bursts into life first try then it's most probably the battery causing an under voltage. Batteries can cause all sorts of issues.

You can get an ODB2 Bluetooth adapter off eBay for about ten quid. Then get an app called torque for your phone. I leave mine plugged in all the time on my Nissan to keep an eye in boost pressure

The g13b is the single cam isn't it? (I get confused :S )

The only thing that works with them is the Rhinopower interface, you can get one from the shop, it isn't obd2 compliant.