Limp Mode at 3k revs - Focus 1.6 TDCI

[superhans88]

I have an '07 1.6 TDCI Focus that I've had since 2010 and now has 172k on the clock. It's been well looked after and serviced and maintained regularly, still on its original clutch, DMF, DPF, injectors and Turbo.

It's started the annoying habit of going into limp mode as it approaches 3k revs, making overtaking manoeuvres somewhat scary... If I let the revs dip back to around 2k it seems to sort itself out without having to turn the engine off.

I have an intermittent warning light that the code reader picks up as 'DPF not operating at full efficiency' or something similar, but this comes and goes independently of how often it goes into limp mode. I fully expect the DPF to be near the end of its life but there's no signs of diesel being dumped into the sump which has happened in the past when it failed to regen. That was solved by a garage running a clean on it a while back.

Are there any other potential causes for this apart from the DPF? This is the only code it's showing but I've read it could be fuel filter (not likely as replaced last year), injectors, wastegates, hoses etc? Not really sure it there's any stop gap fixes for DPF as new one seems to be near £1k

Cheers

[Blanchimont]

does it do it when idle?
when it's in limp does it read the dpf?

[superhans88]

No issues at all when idling. Doesn't seem to be any connection between when the light comes on and when it goes into limp.

[stanglish]

If you hold 3.5k revs in netural for a minute or so, does it trigger the issue then or are you rev-limited in neutral like modern Fords? Best to check after a run when the engine is warm. I don't think DPFs run in neutral, only under load so this might give you a clue if it's related.

Logic seems to suggest it's trying to trigger a DPF, noticing that it's full of clogged and stopping the DPF routine.

It might be worth taking it on a run and keeping it <3k to get the engine full warm then ramping up the load quickly to >4k like dropping to 4th on the motorway. Realistically that seems like the best chance you can give the DPF to run the burn routine properly.

If you have an OBD Code reader I think there are other DPF related codes that may also help you diagnose if it's clogged.

[cknotty]

I had a 'DPF efficiency below threshold' code come up on mine a while back - replacing the pressure sensor hoses did the trick.

170k on the original DPF is good going! Mine needed doing at 106k, had a reconditioned one put in & now on 187k, original clutch too

[superhans88]

I think I had a pressure sensor hose replaced a while back so not sure if it could be that. What did it cost to have a reconditioned one put in? I've seen that you can get them removed for about £500 but this is questionable from an MoT point of view now?

Doesn't seem to make any difference whether I try and hold it at 3k revs or accelerate up to it. There's a point just below 3k that it just won't pass.. I'll get it warmed up and try in neutral though

[E-bmw]

superhans88 said:

I've seen that you can get them removed for about £500 but this is questionable from an MoT point of view now?

It is not questionable at all, it is both 100% illegal & an instant MOT fail if it is seen by the tester.