Cranks but dose not fire when it wants to (electrical)

[Elvis Greenwood Junior]

Hi there

I have just stupidly bought a Y reg Mondeo

It is a good runner apart from the fact that when you turn the key to start it some times it just cranks over and dose not fire and then and again it dose fire and the engine runs. This problem is getting worse every time!

Where could the problem lie? Is this a regular fault in the wiring that this modal of car has and that anyone knows about? Or could it be a hundrad and one things that means a trip of down to the nearest computer ECU reading garage can advise?

Thanks!

EGWJ

[TomsFocus]

If the cranking speed is good despite not firing, and there's no common scenario (such as leaving overnight or parking on an incline) then the issue is often caused by the immobiliser not disarming when it should.

Do you have a spare key that you could try, in case the problem lies with the key fob chip?

Having the fault codes read with Ford specific diagnostics would be the next best step if the problem is the same with 2 keys.

[nicam49]

Hi, sorry to disagree with Tom, (sorry Tom) but when the immobiliser  is active, you WON'T get any cranking. It prevents the starter motor from turning over. 

Elvis, What model have you got? Petrol, diesel, TDDi or TDCi? Duratorq or what? need some detail in order to help 

 

[Elvis Greenwood Junior]

its a Y reg Mondeo LX petrol

[Freddy42]

Had similar on the ST.  Removing and cleaning the negative chassis connections cured it. Worth a try.

[nicam49]

If you don't know how long since the fuel filter  was changed, it would be a worth considering fitting a new one.