Ford S-Max 1.8 TDCI - S-Max 1.8 TDCI - Misfire under load.

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Sun 28 Feb 2016 08:10
Ford S-Max 1.8 TDCI - S-Max 1.8 TDCI - Misfire under load. - Richard30

Hi Guys,

I have an unusual problem with my S-Max...

Under load the car misfire's and really struggles to rev. However, the really peculiar thing is that it is particularly bad when the fuel tank is full and becomes less noticeable/problematic as the tank empties. At about 1/4 tank full and less, the car drives near perfect. As an example, yesterday the car was driving near perfect (even when giving it lots of welly!) but only had 100 miles range left, I then filled up and the car almost immediately started misfiring and struggling to rev under load.

If it was a petrol, I would say the misfire/struggling to rev is like when the coil pack is failing.

It’s going into the garage this week but any help/ pointers would be great.... Thanks

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Sun 28 Feb 2016 10:50
Ford S-Max 1.8 TDCI - S-Max 1.8 TDCI - Misfire under load. - Peter.N.

Sounds like fuel starvation, has the fuel filter been changed recently? If it has an in tank pump that or its circuitry could be failing. Do you get eny smoke from the exhaust when its misfiring?

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Sun 28 Feb 2016 10:55
Ford S-Max 1.8 TDCI - S-Max 1.8 TDCI - Misfire under load. - Richard30

Sounds like fuel starvation, has the fuel filter been changed recently? If it has an in tank pump that or its circuitry could be failing. Do you get eny smoke from the exhaust when its misfiring?

I thought it may be the Fuel filter but don't understand why it would be worse when the tank is full, and conversely better when the tank is emptier.

There might be a puff of smoke when it misfires, but hard to see...

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Sun 28 Feb 2016 10:59
Ford S-Max 1.8 TDCI - S-Max 1.8 TDCI - Misfire under load. - Richard30

Sounds like fuel starvation, has the fuel filter been changed recently? If it has an in tank pump that or its circuitry could be failing. Do you get eny smoke from the exhaust when its misfiring?

I thought it may be the Fuel filter but don't understand why it would be worse when the tank is full, and conversely better when the tank is emptier.

There might be a puff of smoke when it misfires, but hard to see...

No the filter hasn't been changed for 60k....:(

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Sun 28 Feb 2016 11:35
Ford S-Max 1.8 TDCI - S-Max 1.8 TDCI - Misfire under load. - Wackyracer

No the filter hasn't been changed for 60k....:(

Must be a due a change then? blocked filter sounds like a possibility.

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Thu 3 Mar 2016 08:45
** Resolved ** Ford S-Max 1.8 TDCI - S-Max 1.8 TDCI - Misfire under load. - Richard30

No the filter hasn't been changed for 60k....:(

Must be a due a change then? blocked filter sounds like a possibility.

Been into the garage yesterday....

The IMV (Inlet Metering Valve) on the fuel pump was partially blocked restricting fuel flow.

Once cleaned out, the problem has been resolved. Also had a full service (inc fuel filter).

I'm a happy bunny...

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