misfiring diesel

H

halfacar

Member
Hi all, I have noticed recently that my car has developed a "misfire" when accelerating it feels like a plug is playing up on a petrol engined car but its a diesel. I had the car serviced last week at an independent garage that is run by an aquaintance of mine and he said he had done a code check and no fault codes were showing. the car starts no prob. He suggested it could be a dodgy injector but he wasnt really sure. I have seen reports of injector loom problems but they sometimes seem to come with warning lights coming on which I dont have. The car is a 2004 tdi90 and I think its a sport but I might be wrong with 92k on the clock. Any help would be appreciated.
 
Do you notice it most under partial throttle?

Had the same thing recently on my 90..... Mass Air Flow Meter. Budget between £150-£300.
 
Welcome.
The faulty injector wiring harness does start to throw misfires for some time before it actually chucks up any warning lights on the dash or indeed log any fault codes. Mine did exactly that - for a few weeks it was just a random occasional misfire which steadily got worse, and then it threw some warning lights on the dash and went into limp-home.

When does it misfire, and in what gears? Ie under what conditions? If it's when you're accelerating hard in, say, 3rd gear at higher RPM, it could be indicative of a boost leak, or as you have a 90, it could also be sticky turbo vanes.
 
Thanks for your quick response, it seems to do it under acceleration in any gear which when you are thinking of overtaking makes you scan the horizon a little more carefully than you might have.
 
Does it trigger the car to lose pretty much all power after a bout of sluggish acceleration - ie does it go into limp-home, which only then gets better if you switch off the engine? Or is it just a bit juddery?
 
Mine is similar, feels exactly like a misfire at around 2k rpm usually under load ie going uphill or trying to accelerate quickly. Can't decide between MAF sensor, fuel filter or sticky turbo. Anyone else experienced this? It's a 2004 tdi 90 with 65k on.
 
I'd start with the fuel filter if it has not been changed recently. Not tried this myself but I think the engine should run ok with the MAF disconnected. If it runs worse then it could indicate the MAF needs replacing (or try cleaning it with carb cleaner spray)

Cheers Spike
 
I have a similar issue currently on my '04 TDI90

Fuel filter recently changed. No improvement.
EGR cleaned out & blanking plate recently fitted.
Yellow engine light came on within 200 yards.
Not sure if it will run more cleanly with some longer runs.
I will ring the garage again tomorrow & suggest the MAF possiblity.

Balla :/
 
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