MK6 Fiesta Zetec S intermittent stalling/not revving problem

[Tomo72]

Hi all,

My wife has a 58 plate MK6 Fiesta 1.6 Zetec S with only 40 odd K on the clock and it has intermittent starting problems.
Sometimes it will start but will not rev at all, if you floor the throttle the engine RPM will steadily decrease and stall. Sometimes it will start then immediately stall. This can happen two or three times, on the 2nd or 3rd start all id fine. Other times it will be perfectly fine once started. Whether the engine is warm or cold makes no difference. A friend amateur mechanic of mine said he had a similar issue with a 58 plate and he replaced the throttle pedal that cured it. I have done this with another, not new but used, one but the issue is still there. The ECU shows no fault codes. Any ideas anyone?

[zain611]

Is it petrol or diesel? 

[Lenny]

1 hour ago, Tomo72 said:

Hi all,

My wife has a 58 plate MK6 Fiesta 1.6 Zetec S with only 40 odd K on the clock and it has intermittent starting problems.
Sometimes it will start but will not rev at all, if you floor the throttle the engine RPM will steadily decrease and stall. Sometimes it will start then immediately stall. This can happen two or three times, on the 2nd or 3rd start all id fine. Other times it will be perfectly fine once started. Whether the engine is warm or cold makes no difference. A friend amateur mechanic of mine said he had a similar issue with a 58 plate and he replaced the throttle pedal that cured it. I have done this with another, not new but used, one but the issue is still there. The ECU shows no fault codes. Any ideas anyone?

Try the MAF sensor 

[Tomo72]

29 minutes ago, zain611 said:

Is it petrol or diesel? 

Sorry, it's petrol

[Tomo72]

26 minutes ago, Lenny said:

Try the MAF sensor 

Try cleaning or replacing?

[Lenny]

3 hours ago, Tomo72 said:

Try cleaning or replacing?

If the MAF cleaning foam isint too expensive from Halfords I'd try cleaning first but if it's half the cost of a replacement then I'd just replace the MAF sensor, 

Sounds like it could be it because it tells the engine to use more fuel when cold and less when hot, 

Also don't touch the MAF sensor with your hands it's very sensitive, 

Replacement may also aid economy 

Alternativly could be fuel filter if fitted although if it stays running for a long drive when it does stay running; its likely not the fuel filter 

[Tomo72]

2 hours ago, Lenny said:

If the MAF cleaning foam isint too expensive from Halfords I'd try cleaning first but if it's half the cost of a replacement then I'd just replace the MAF sensor, 

Sounds like it could be it because it tells the engine to use more fuel when cold and less when hot, 

Also don't touch the MAF sensor with your hands it's very sensitive, 

Replacement may also aid economy 

Alternativly could be fuel filter if fitted although if it stays running for a long drive when it does stay running; its likely not the fuel filter 

Thanks Lenny,

That gives me a starting point.

[isetta]

some cars run on a default MAF setting if the MAF is disconnected.  Some don't even have one eg. my 2001 Mk1 Focus 1.6 petrol had no MAF - not removed, they just didn't come with them.

So if you disconnect the MAF and it runs better it's pretty certain it's the MAF.

However disconnecting MAF will cause a fault code to be logged and might put the red light on but I assume you can clear that as it seems you have a fault code reader

[Tomo72]

13 hours ago, isetta said:

some cars run on a default MAF setting if the MAF is disconnected.  Some don't even have one eg. my 2001 Mk1 Focus 1.6 petrol had no MAF - not removed, they just didn't come with them.

So if you disconnect the MAF and it runs better it's pretty certain it's the MAF.

However disconnecting MAF will cause a fault code to be logged and might put the red light on but I assume you can clear that as it seems you have a fault code reader

Thanks, yes I have a code reader. I've been doing a bit of research and it looks like the car doesn't have a MAF but has a MAP. If it did have a MAF then where would it be?

Picture taken from the internet, looks identical

TIA