Audi 80 tdi juddering bucking jerking

[krissib]

dont know if any1 is still reading this thread, ive got a 1993 audi 80 1.9 tdi, its about 165k now was 100k when i got it, its juddered since soon after i got it, the person i bought it off swears it never did it b4 but it had stood still for 6 years or so....

anyway just wondered if it helps any of you, but my car is an automatic and still judders...

recently (in the last month) its started dying at certain speeds... feels like the turbo kicks in and out... which is even more annoying than the jerking.... although the jerking seems to have stopped as much, it now feels like im losing half the power every time i hit a slight hill....

is it too late to cut the wire?? i was hoping whatever it was that needed replacing would also stop the jerking, but after reading all these pages im now more confused than before!

my fuel gauge does weird things, it lies to you about how much is in it if its under halfway, can drop to nothing or hover in between the reading or empty... ive read loads of posts that say fuel pump which is plausible but one post did say about dry joints in the dash.... does this tie in with the blue/white wire theory?

im fairly sure i get air bubbles in the fuel line as well, god knows where from, ive replaced the fuel line (cos it failed the last mot on it)

i seem to find new filters (air/oil/fuel) seem to stop the juddering for about a week then it kicks in again....

i modded the woven waste pipe as well soon after i got it, replacing with a solid plastic tube.... that seemed to help for a bit but i dunno whether to just ebay it and try and find another car or whether to venture further....

i was hoping after 20 pages there'd be a reason that all this happens... some people say about a turbo pipe... sounds like mine is starting to go, or could it be the computer thing idling me out because of the fuel gauge etc....

im more confused now than ever lol and i need a reliable car!

[scotty33]

I suggested the problems with the dash circuit boards could be related to the juddering, this was when there did not seem to be any thing else to try. Soon after, there were posts/links about stripping and cleaning the pump controller. This seems a more likely cause of the problem, though if you want to cure the dash problems you may have to strip the instuments down anyway! (But it could just be the tank sender?)
The loss of boost pressure sounds like possibly a boost leak, or maybe a sensor failing, either way a fault code scan should point you in the right direction. See the VAG-com forum to check whether there is anyone near you that could do a scan?

[hawkeye1975]

My Audi 80 TDi 179k has the juddering and cuts out every now and again, mostly when its warm and dry. When pulling i can feel the turbo come off the boost just b4 the cut out starts, only does it for a split sec. Bloody dangerous when overtakin though!!!

My speedo has a habbit, rarley of stopping working, when this happens, she drives perfectly, no judder or cuttling out?

Sound similar ??

I havn't cut the wire yet, i would rather find out Why first, rather than butcher, but if all else fails.........
Can'nt afford another car and she just passed ANOTHER mot !!

Can we get a definitive summary of symptoms and remedies??

Peter

[krissib]

yeah exactly.... follow the cable to both ends etc see what it actually does!!

mine is automatic anyway, most of these posts speak of manual so i don't even know if my car (with no clutch) can handle being rougher, automatics arent supposed to stall!!

most people say its the electronics of the fuel pump that cause the judder anyway, and its not worth me replacing that part with a brand new one really, its done nearly 170k and ive driven it (with the judder) since 100k on the clock... its a bit annoying sometimes when the cd jumps all the time, but it hasnt caused anything else to go so far....

the turbo dying is the reason ive started taking an interest in all of this, hoping the juddering was caused by the same thing.... i thought wrong lol

i think ill wait till it dies then i might just buy another 80 or an a4 and make sure i test drive it for a good hour b4 i buy it!

[krissib]

o yeah ive never had a problem with the speedo... only a fuel gauge that guesses when the tank is less than half full.... and 1 panel light not working (i cant see the clock on the rev counter, and round the 30mph mark)

only other thing that gets me is it has manual windows yet central locking and electric mirrors n sunroof lol who thought of that idea?

[scotty33]

I dont know if this is technically accurate, but as I understand it, the vehicle speed sensor gives you a speedo reading, but it also 'tells' the ECU that the car is travelling. The ECU then gives a 'softer' throttle response for a smoother ride.
The VSS can fail, or the diff bearings wear, or driveshafts wear either of which can affect the VSS. You could spend lots of money solving these problems but snipping the wire (as I understand it) cuts the ECU signal, which means no more juddering, but you suffer a harsh throttle response. (gentle right foot required)
As your symptoms seem to disappear with the speedo signal failing, I suggest you either cut the wire or maybe try a new VSS, but if there is a diff bearing/driveshaft problem, the new VSS may not help?
There is another possible cause of juddering, this requires a stripdown and cleaning of parts of the injection pump see links: unfortunately they are in German! try Babelfish for translation?

http://community.dieselschrauber.de/...c6c2bd487b6153

http://community.dieselschrauber.de/...c6c2bd487b6153

http://babelfish.altavista.com/babel...c6c2bd487b6153

I guess the second scenario applies to cars that do not benefit from unplugging the VSS/cutting the wire?

anything wrong here, please feel free to correct it, this thread is so long now I can't say I've seen it all or remembered it accurately!

[scotty33]

the turbo dying is the reason ive started taking an interest in all of this, hoping the juddering was caused by the same thing.... i thought wrong lol

Not necessarily, from what Hawkeye says, his car does not suffer any boost/power loss when the speedo fails.
I had not heard of this problem affecting power levels before but you may have been right all along.
I just regurgitated the usual suspects for power loss, let us know how you get on?

[krissib]

i have never had a problem with the speedo... and yet i get the power loss intermittently... usually wet/damp days which is the opposite to every1 else...

and again, please confirm whether or not an automatic can handle not having the smooth accelerator cable, a stalled automatic can mean smashed gearbox/pistons/allsorts as far as im aware!

[shedavant]

Hi, just a quickie, Hows everyones hunting idle?? Mines like a rolling throb! for a few seconds it ticks over fine then drops to a throbbing hunt for a few seconds and so on, as if pressure builds up and also it puffs strong fumes while hunting!! also them damn bubbles in fuel line when i give it a boot ,are baffling me as iv changed and checked everything and all is airtight!!!.. is there any sort of manual for this model or arnt they worth printing as they carnt be fixed?

[krissib]

from what ive heard the air bubbles are caused by corrosion in the tank, small filings of metal that cling to things and generally f*ck everything up....

the electronic bit of the fuel pump is the fault appparently, althou i dunno about spending 4 bills on just a fuel pump!

idle.... im assuming u mean tickover, revs just below 1000 and sounds like a fanbelt is loose but it isnt, its always squealed till its warm, again annoying but no long term damage!

got to drive to birmingham and back this weekend should be fun! if u see an L reg green 80 on the m6 doing 14 miles an hour give us a wave !

kris