'Hiccup' Problem - TDCi Fiesta

[RDE]

My G/F has a 57-plate 1.4 TDCi Fiesta. It had a fault on a long trip in the past where the supply of power would be interrupted for a split second every now and then, causing a sort of hiccup sensation. The fault was fairly random and not related to any particular inputs from the driver that I could determine. At the time we took it to the dealer to have it checked out, but they found nothing. Since then it stopped for a while.

This fault has now started again. As another visit to the dealer is likely to bring the same result as before, does anyone have any ideas what could be causing this and how to rectify it?

Many thanks if anyone has any ideas.

[HellDiver]

The 1.6TDCI Econetic Focus with less than 2k on the clock I had last week was doing the same. A little cough now and again. Annoying.

[M40WST]

If your car has DPF (most modern diesels do), it will be the DPF doing a burn to clear out the filter, my old Fiat Bravo 1.6 MJET used to do it every few thousand miles.

[RDE]

Thanks for the responses. I'm not sure what DPF stands for, but this is far more frequent than you mention. Sometimes it won't do it for hundreds of miles it seems, but on occasions it can be every 30 seconds or so for a few minutes. Very puzzling.

[Zad]

Diesel Particulate Filter. Basically it traps soot from the exhaust and now and then squirts urea on the filter (yes, basically it wees on it) which, combined with the exhaust temperature, burn off the particulates. It does this every so often. Not sure what the period is, 500 miles maybe.

It might be worth getting the fuel filter changed.

[ymwoods]

It could be something as simple as a bad earth to crap in the fuel filter/pipes. Since its a Derv we can rule out funky HTC leads not giving a good spark and the like but just general hiccups can still be from pretty much anything.

Does it happen more when it is warm, when accelerating/decelerating etc? or when the car is wet?

[RDE]

Obviously i'm not driving it as must as the g/f is, but I would say it usually happens when it is warm, generally when maintaining speed but has happened occasionally while accelerating, and things such as weather conditions don't seem to make any difference. As I say, it can be very regular but then sometimes not do it for ages. The problem for a dealership or mechanic I guess being that you can't tell straight away if an alteration has actually cured the problem, due to its random nature.

Thanks again for the replies so far.

[ymwoods]

I would start by changing the Glow plugs and whilst your their just check the quality of the connections and that they are not rusting/corroded. It's something you should be able to do so only the cost of the plugs.

It could also be something to do with the EGR valve which is known to cause "Kangarooing" if it gets full of crap and starts to stick open/shut. Again this is something that you could probably do yourself but make sure you have the time to faff about. It is relativly easy on the Astra's I have done before, but have never touched a Fiesta. Best part though is that, if done yourself, its free.

Next look for airleaks around any pipes and connections coming from the turbo or induction pipes. Best trick is to get someone to rev it just enought to turn the turbo on and then use some tissue paper and see if you can spot it being blown when next to a pipe. Just be mindfull of how long you have the turbo running for when not moving, which is why you dont want to rev the crap out of it. (no airflow to cool it)

Next I would try changing the MAF sensor but from the dealers this is the best part of £100 and ussually if it is these then it will cause it to stall when cold too so not worth checking out unless every other option has been checked.

HTH

[Fizpop]

May be a silly response, but does it do it when your aircon is on? Mine's a nightmare for this, you feel a slight, momentary drop off in power as the compressor (not Kompressor ) kicks in, which could be described as a little cough. A little cough with a lowly 68bhp means a lot!