starting and tickover probs HELP!!!

[seamusshaz]

hi i have a renault megane 1.4 16v on a 02 plate this last week it is failing to start after been left for a few hours.. the only way i seem to be able to start it is by bump starting it and when it is started it has an eratic tickover until it has been driven a few miles and has warmed up i have had it on a diagnostic and there are no fault codes coming up can any one shed some light on this as its already cost me £150 for garage to look and find nothing cheers seamus

[BIG-TED]

At a rough guess crankshaft sensor, very comon and problamatic on all the renault range, diag test doesn't show anything due to it nor registering only when engine is running. Starts with bump because the engine speed is incresed enough to give a higher voltage signal in the sensor.

95% sure it'll be this.


Ted

[morphias]

hi ted have been there with seamus when the car has been doing this... the car seems to start ok after it has been run for a while its only when left for a few hours it dosnt seem to want to start and when u eventually get it started it stinks of petrol is this how them crank sensors work cheers

[Pegasus]

its only when left for a few hours it dosnt seem to want to start and when u eventually get it started it stinks of petrol

It will stink of petrol if you spend ages cranking it over because the fuel isn't being burnt if it isn't starting.

[Chuckie]

spark plugs?

Spark plug find it harder to ignite the fuel/air mixture when the engine is cold. They work better when its warm, but not hot.

Is it a bit juddery to drive when its cold?

[Over Carl]

I also first thought crank sensor, but don't they normally not work when heated up when they are going?

[morphias]

hi yes its a bit jerky when driving cold its had brand new coils fitted and plugs so its not them the garage said he fitted a new crank sensor but didnt make any difference its hard to find the problem with out chucking loads of money at it .....