I've had my R reg diesel Felicia for a little under a year so this is my first winter with a diesel. I've noticed some problems running lately and brought the service forward by a month or two to sort it out but have not had any improvement. I'm wondering if there is a fault or whether this is what I should expect during the cold weather.

I find that there is a flat spot sometimes with a light throttle and if keeping a steady speed at a light throttle this can turn into a misfire (if that's the correct word for diesel) which clears when the accelerator is pressed further. The problem with this is in traffic I'm constantly catching up to and falling back from the car in front.

At the same time as this developing, fuel economy has dropped off by anything up to 50 miles less in a tank.

I do quite a few short trips in a day with longer trips on weekends. Other weekends the car just sits in the garage.

1. I had a new cat before Christmas so could there be a link?
   
2. Is it just the cold weather?
   
3. The garage that serviced it put in glow plugs and fuel filter but can't find what's up. They suggested the injection pump as they think this has had work before (blue paint sealing it). Could that be it?
   

Please put my mind at rest or tell me the worst (break it gently) as it's doing my head in.

I find that there is a flat spot sometimes with a light throttle and if keeping a steady speed at a light throttle this can turn into a misfire (if that's the correct word for diesel) which clears when the accelerator is pressed further. The problem with this is in traffic I'm constantly catching up to and falling back from the car in front.

Hmmm. Sounds interesting!

My Felly does do this when the engine is cold but is fine when warmed up. I assume that you've concidered this though.

The Diesel could be waxing (going all gloopy in the cold) but that needs seriously cold weather to happen. If you're living in England that probably wont happen.

The pump timing could possibly be out (pure guesswork)

I'm in the midlands, cold at the moment but by no means Siberia. It warms up until the needle sits just touching the lower edge of what I take to be the "normal" line on the gauge irrespective of whether I take a long run or a relatively short one. Either way, it reaches this position before I switch off on most, if not all, trips out. The problem doesn't seem to be there from cold - starts about 5 minutes in.

I'm going to try some injector cleaner and maybe drive it a bit harder too. I tend to drive it gently ( not wishing to sound a pansy ) and have been reading that they need a bit of a thrashing occasionally to keep things clear. Going to go over all the electrical connections too, bit intimidating in there - my last car was a 1966 Austin 1100.

Thanks for the advice, I'll check temperature sensors first.

Try tossing in something like millers dieselclean or power plus for diesels, this can help a lot of older cars.

If this doesn't help then i had injectors cleaned out on my car and the fuel filter changed at the same time which helped out massively. Saying that I wouldn't think it's the cold as my old car had a fuel heater (back of the XUD engine, which leaked and was more trouble than worth) .

I am not a mechanical expert, only learnt by fixing my own cars (the last 4 have been diesels) Please dont think that I know what I'm talking about, but I doubt if the problem is electrical, older diesels dont need electrics to run - just to start. Most stalling problems are due to bad fuel delivery.

If cleaning the system doesnt work, check the pump timing. If that doesnt work, cry.

Also in my experience of diesels, you do need to "give them some beans" every now and then. Dont ever go above 5000 revs but dont be scared to push it hard. It can take it. I drive my cars to death but only one diesel engine went on me and that was a broken timing belt. Usually, the rest of the car went long before the engine did.

They did the timing belt when I bought it so I think it should be ok to wind it out a bit. Do you know if there's a rev limiter fitted? I've no rev counter so don't want to overdo it. (Still sounding like a softy here, arent I? )

Thanks both for the advice.

I have been looking at the post on diesel "misfire". My Felicia recently started doing it too. It has done 113000 miles. It starts readily and idles perfectly. The misfire happens at about 1500 to 2000 reves in any gear. Stops when throttle is pressed or released. Have injectors checked - all OK. Electronic diagnosis showed no faults. For the first time ever found water when draining the filter, so will get the filter changed. But would water in the fuel cause problems only over a narrow range of revs.

Did wonder whether the injection timing was out, but thought that that would give misfires over the whole range of revs, not just 1500 to 2000.

The injector pump is the tthe other possibilty, but surely that would show up in the elecronic diagnosis.

What a mystery! Still such things all add to life's rich tapestry

But it is great to get others' thoughts on the subject - I am a new recruit to the forum, but it seems great

The Felicia story. Trouble with misfiring got worse. Had 3 lots of electronic diagnosis. One said EGR valve, another fuel injection pump problems and third no faults. Replaced split EGR pipe - fault unaffected. New fuel pump 600 pounds and 250 to fit, Decided time had come to say good bye. A case of a good German engine scuppered by a poor British fuel pump? Until this trouble went and sounded as though it was brand new