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sean, UK Ford Master Technician
Category: UK Ford
Satisfied Customers: 3105
Experience:  Ford Master Tech since 2001 & MOT tester mechanic since 1984.
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My 2006 smax has an intermittent starting problem. Engine

Customer Question

my 2006 smax has an intermittent starting problem. Engine turns iver but wont start about 50% of the time. The rest of the time works fine!
Submitted: 1 year ago.
Category: UK Ford
Expert:  sean replied 1 year ago.

Hello, I hope the following assists you.

If you haven't already done so have a diagnostic scan carried out on the PCM to check for stored fault codes and act on any that are evident.

There are a couple of common faults that can give the symptoms you describe.

If this happens after the car has been left for a time such as over night then check for air ingress into the fuel system, air will not allow the fuel pump to create enough pressure so you need to crank the engine for a long time before the air is expelled. The 2.0L diesel has a transparent pipe either from the injector return or where the feed pipe is clipped to the manifold so either will allow you to see air. It's unlikely to be this if there is no pattern to when the fault occurs but it needs checking.

Check the air shut off isn't sticking closed, this closes when the engine is switched off and then will open again when the engine stops. The EGR intake is close to the air shut of valve and deposits form on the shut off flap which build up enough to cause the shut off flap to stick. If you remove the intake hose at the inlet manifold you'll see the flap.

Another point is the crank sensor can cause problems usually if dirt or oil has gone on it, if this is the case this doesn't always store a code in the PCM.

There are other things that can cause the symptoms you describe but start with these points and let me know if I can advise any further.

Best wishes,


Customer: replied 1 year ago.
if the engine turns over without firing does that mean it's not an immobiliser problem? If it is the crank sensor how do you prove it? Do you just have to replace it and how big a job is that?
Expert:  sean replied 1 year ago.

Hello again.

No it shouldn't be an immobiliser problem as this usually disables the starter motor as well you would also get the immobiliser active message.

To check the crank sensor you would need a diagnostic tool that can read live data, you can then check the signal from this sensor when the fault occurs and if there is no signal then replace the sensor. The sensor is easy enough to change it is 1 bolt then spin it forward to clear the cambelt cover. If you do have access to a live data then this would make it easier to diagnose the problem as you can check the fuel pressure at cranking this will tell you straight away if there is air in the system.

Start with the points I mentioned previously especially the shut off flap.

Let me know if you have more questions regarding this and I'll reply as soon as I'm able to.