Starting problem

[simo2k]

Hi all I've got a 1.5 dci megane with a starting problem sometimes when I press the button sometimes it fires up other times it cranks but not fires up. I've been told its fuel draining back thing is I can start it first thing no problem turn it off then restart,turn it off then just cranks no start. I've replaced the crank sensor, cam position sensor still no luck. I've had the car scanned only fault is camshaft position coherence.

I'm tearing wots left of my hair out trying to solve this one any help appreciated

[chewbacker]

I would recommend you get canclip hooked up to it as only this diagnostic system shows you a uch bsi and ecu status as you carry out requests. It will flag up as live data as to what parameters are out of tollerence. Fuel drain back is very unlikely. Check your engine ecu model which is on the ecu on a sticker and compare it TAMAR electronics website. You select your ecu by the model and it gives a list of common problems. Really helpful guys if you phone

[AlexB]

If someone who opened the bonnet said this, then he probably saw air in the clear pipe to the high pressure pump. There can be a microscopic hole in a fuel line or a problem with the filter... The fuel lines operate under negative pressure and may suck air in if there is a hole. It can be also the fuel return circuit. Read the manual, understand how it works and check everything. It is very basic. The other things to check are the starter revs and preheating.

Hi all I've got a 1.5 dci megane with a starting problem sometimes when I press the button sometimes it fires up other times it cranks but not fires up. I've been told its fuel draining back thing is I can start it first thing no problem turn it off then restart,turn it off then just cranks no start. I've replaced the crank sensor, cam position sensor still no luck. I've had the car scanned only fault is camshaft position coherence.

I'm tearing wots left of my hair out trying to solve this one any help appreciated