115bhp TDi Misfire?

[Gj Moss]

Hi Everyone,

Our 2002 TDi 115bhp is suffering from a misfire around 1500rpm, particularly when under quite light load/gentle acceleration.

It seems to be getting worse, and wasn't improved after the recent major (incl. cambelt) service at 80,000miles.

Any ideas/suggestions gratefully received!

Cheers, Graham

 

[sssstew]

what happens if you floor it at that rpm just to test, does it stop?

 

[Gj Moss]

No, it seems to do a single mis-fire, then runs smoothly up throughout the engine speed range.

It's just a bit odd - just a misfire as I tip back in from a trailing throttle, sometimes as I drive through that engine speed.

 

[sssstew]

so from low revs (ie from 1100 for testing purposes only) right up through the range, if you floor it, then it will still do it?

 

[ktreadwell]

more for my own curiosity, how do you know its a mis-fire? I have the same car.

K

 

[Gj Moss]

Erm...subjectively it feels like a mis-fire. The engine "hiccups" once, and there's a longitudinal "shunt" of the vehicle. If it happens at lower speed, it can be severe enough to cause passengers to jolt fore/aft in their seats.

I've seen other posts suggesting the dual-mass flywheel could be at fault - seems very odd that this part could have such a narrow-band fault.
Another post I saw, for a similar sounding issue, suggested injectors could be the root cause. However, I don't spot any smoke coming from the exhuast when it happens (a symptom mentioned in the thread).

Frustrating, as it's infrequent in occurance, but can be pretty significant. I always fear it 'jolting' one day and not running again!
Still, it's had the issue for 9 months or more now, and hasn't worsened I guess....