Fiesta EcoBoost 1.0 limp mode issue 2000rpm

[SteveC100]

We recently bought a 64-plate Fiesta EcoBoost 1.0 which has a recurring but intermittent fault. During acceleration (from about 2500 rpm upwards) there is sometimes hesitancy in its power delivery that feels like misfiring. This sometimes, but not always, leads to the engine putting itself into some kind of safe mode where it limits the rev range strictly to 2000rpm. The problem usually happens when it is fully warm, often about 15 minutes into a journey. It has done this roughly eight times within the last two months – but, of course, never when it’s at the dealership. I think that they think we’re making it up.

The thing is, no engine problem/management lights or messages are displayed on the dash and no entries are ever made into the engine management unit’s log. We and our main Ford dealer are having real trouble tracking down the cause, so I would be interested to hear from anyone who has experienced similar issues.

[JohanL]

Hi Steve,
Could you share what the problem was?
I currently have something that looks very familiar and the mechanic doesn't know what it is.

Thanks.

[PisstNBroke]

I'd be looking at HT leads and coil pack, had a similar issue with a fiesta but 4 cylinder engine.

[JohanL]

The error code is P0253-II, this is related to the fuel injection pump.
This pump has been replaced 2 years ago because it had this same issue all of a sudden.

Now I first had this issue every now and then (no engine light) and switching the car off for a minute would reset it. By now the engine light is on constantly but the car goes into limp mode after 2-3Km driving.

They've replaced the internals of the pump to be sure there was no issue with that, but that didn't help at all. Later they've redone a connector related to the pump (don't know what exactly) and the car worked again for 2 months without any issues.

The spark plugs have been replaced when the car had done 60.000Km, its now at 72.000Km.