Hmm, misfiring TDi

dan_b

dan_b

A2OC Donor
Got in my car this afternoon, pootled up to the supermarket. On the way back, stuck in slow traffic, noticed the car was very lumpy at tickover and at lower RPM than usual. Then on extremely light throttle in first, acceleration was lumpy too around 1500-1900 rpm. Felt exactly like a misfire.

I'm guessing this is the failing wiring loom to the injectors fault that seems to be fairly common on TDis? Is there any quick way to check and confirm?

If it is, where can I get a new loom from, for how much, and is it easy to fix?

Dan
 
Cheers Ive not had any warning lights come on as yet. Im half way through a tank of Sainsburys best with the usual dose of Millers in there got 260 miles out of a half tank on this one my best to date. Will keep an eye on it might try cleaning the loom connector...
 
I Wonder if it could ba a case of using to much of the millers
may have dislodged a bit of gum or dirt or something
could it block the injectors .......
 
Took the car out this morning, misfire is way worse than on Saturday. Possibly due to the air being cold and damp, but not a good sign in my book.

Still no warning lights on the dash, but I would expect some error codes logged?

Is there anyone with a working copy of VagCom near Richmond who could come over and help me pull any fault codes? My version has stopped working (or rather the laptop on which it was installed has died and I have lost the install disc)...
 
Dan, depending on the legitimacy (ahem!) of your interface, the shareware version of VagCom can be downloaded from the Ross Tech website - might be quicker than waiting on another member coming over.

Cheers

Mike
 
Unfortunately the same reason I lost the install disc is the same reason I lost the cable... I'm thinking would one of those error code light blinker jobs from Halfrauds do the trick?
 
Dan, i too had a HD failure but since replacing it, I've not bothered to reinstall windows so I've got a cable and no software (and no ETKA or ElsaWin!). I'll let you know if I can install them the shareware version on my wife's windows netbook. Then I could give you a hand.
 
Would someone be able to post up the part number for the 75tdi injector loom? Is it easy to replace diy? In the meantime is there a connector in the wiring I could test and clean to see if that makes any difference?
 
I think the part you need is 045 971 600 and the price is around £45, but double check this with your dealership.

As to fitting/cleaning, it's as simple as whipping off the cam cover and taking it from there. A good cleaning with an aersol contact cleaner can't do any harm in the first instance, but it's going to be a pain to replace everything and then take it all apart again to fit a new harness, if the cleaning doesn't work.

Cheers,

Mike
 
Cheers Mike - what bits do I need to take off the cam cover?
Just to double check, does the loom run all the way back into the ECU, is that straightforward to do?
 
The loom in the head has a connector on the right hand side. big bayonet style connection. twist off.

Id spray some contact cleaner in there first. as that requires no stripping and might ease the issue in the short term, it certainly did for me. but itll just get worse.

the bit youll be replacing is from that connector to the injectors under the cam cover. All rest stays same.
 
Dan.

I was thinking about your problem on my way home from work today. I had a solitary incident of sporadic misfires a couple of years ago. The cure seemed to come in the form of a diesel filter change. The one I removed was full of black, slimy, oily crud. I put a new filter in and it has been perfect ever since. Not a single misfire again. I guess that was at about 70,000 miles so that's how long that original filter had been in. :eek:

Might be worth a shot for £18 or whatever they are rather than a pricey loom. If it doesn't cure the problem it will at least mean you have a nice new clean filter.

Just a thought. HTH.

Cheers,
 
Lee makes a good point, most instances weve seen of the injector harness throw a fault code and most of the warning lights and a chime come on. The fault code too is pretty direct pointing to resistance issues with the wiring. in the wiring loom issue the solenoids dont receive the signals to fire, hence the miss. Of course other fuelling issues could give you a miss.worth checking out fuel delivery if no fault codes.
 
Thanks for the continued input. I had the fuel filter changed when I took the car to Fontain for its AVS service last month and had run a whole tank of diesel through with no probs. Two weeks ago I filled up at Sainsburys as usual added the Millers and went up to Leicester and back with my best ever mileage to the half tank mark then the misfire started with my midweek short London driving trips.
 
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