Audi 80 tdi juddering bucking jerking

[diego666]

Hey there Andy,

not sure about the diesels but the dual mass flywheel has been employed in the turbo gas/benzin cars for almost 20 years. Likely in the tdi's tho.

Also, in the last couple weeks i disconnected the fuse to the instrument cluster-to cancel the VSS signal, to experiment without doing anything ~permanent. THe car is certainly runs better but still suffers if driven over 20 minutes. Luckily i haven't been stranded anywhere (just short trips) and don't need the car most days. I am really thinking it's a fueling issue because at idle, it runs fine indefinitely. Only once i drive it, accelerating under regular conditions, does it start coughing.

Has anyone tried disconnecting the number 3 injector sensor instead of the VSS in order to supply the ecu's fueling signal from the VSS only? Altho if i remember correctly, if the ecu receives no signal from the injector sensor it *may kill the engine.

Because this issue still exists i wonder if perhaps both these sensors in my car are messed, or if changing out relays may help.

what you all think?

d

[allan_audi]

hi to all!! This thread has been very helpful to me.

I have a 1994 audi 80 1.9 tdi with the 1z engine and have suffered the same juddering problems for about a year so i tried disconnecting the wire behind dash and its all but gone just a little harsh if your rough with the throttle.

I`ve just joined this forum so i can ask if anyone has heard of the dual mass fly wheel which has been associated with juddering on diesel engines apparently its fitted to help quieten diesel engines down, i`ve never heard of these until about half an hour ago so if anyone knows if the audi 80 tdi has one of these fitted i would be greatful if you could let me know.

From what i can gather the newer 1.9tdi vw are fitted with them as are some other makes of cars, but not sure about older audi & vw models, i will have a look in my haynes manual to see if that sheds any light on the problem.

hope this will make sense to someone cheers andy!!

Hi, its interesting you mention the dual mass flywheel, because I had suspected this in the past, but was assured by Audi that my Audi 80 TDi (1994) was NOT fitted with one. In fact if you check the parts details at http://www.vagcat.com/epc/cat/au/A80/1994/ it looks like a standard flywheel etc.

BUT!! I don't think I completely trust Audi or Vagcat for the correct info. So basically I was never 100% sure, and won't find out for sure until the clutch goes, sadly (or gladly!!!) its showing no signs as yet!!

[diego666]

While a worn out or overheated clutch pressure plate or broken dm flywheel could create the juddering problem, in mine and most cases i've heard here the motor judders while driving in gear, warm at idle in neutral and when the clutch pedal is depressed fully- makes me think the problem lies elsewhere. Since this thread is defined by a symptom tho, it could have many separate causes. Additionally, a few of the posters here, myself included, have changed transmissions and clutches to no or minor effect.

It is interesting to see tho that other non-diesel topic threads also address this juddering/bucking for countless reasons.

Maybe that would be nice if the cause were a bad clutch/flywheel. At least it would be a conclusive diagnosis!

shake, shake, shake your booty!

d

[allan_audi]

While a worn out or overheated clutch pressure plate or broken dm flywheel could create the juddering problem, in mine and most cases i've heard here the motor judders while driving in gear, warm at idle in neutral and when the clutch pedal is depressed fully- makes me think the problem lies elsewhere. Since this thread is defined by a symptom tho, it could have many separate causes. Additionally, a few of the posters here, myself included, have changed transmissions and clutches to no or minor effect.

It is interesting to see tho that other non-diesel topic threads also address this juddering/bucking for countless reasons.

Maybe that would be nice if the cause were a bad clutch/flywheel. At least it would be a conclusive diagnosis!

shake, shake, shake your booty!

d

When you say you changed the transmission/clutch, did you change the gearbox, flywheel, and clutch components all for new parts?? Did you fit any used/part worn parts?

[diego666]

Mighty fine question Allan,

No, it's a used 5 speed Q gearbox, kept my old center diff (quattro you know), new clutch, existing flywheel but don't know if it's dm or solid, but mech said it was in fine condition and he does alot of them. The car originally had a dmf when it had the 2.2 20v 5cyl turbo, but it may have been changed in the orig conversion to tdi (prev owner), as the final drive/diff's were.

-tiny glimpse into why i refer to the car as Frankenstein... BTW: don't ever buy someone else's conversion, even if it looks correct and works fine at purchase. When something 'goes', it's unchartered detective work.

d

[audijay73]

ive had the juders to ive been trying to eliminate this problem following other peoples efforts and advice ive changed air mass blanked off egr valve ,replaced vacume hosses fitted new egr , put it on a mates hand held vag com it picked up boost presure sensor priced one up 160 quid pluss vat but couldnt find it on my car so after being stumped for abit i cleaned out crud in plenum box cleaned all boost pipes and electrical connections , took off actuator thing to waste gate pushed in and out thin oily liquid came out could this be cause of problem as i atached football pump to actuator pumped it a few times and the rod that connects to waste gate moved in and out freely put everything back to gether clean and with new gaskets the problem has nearly gone but its not perfect when and if i solve this i want to tune this engine is it worth it its done 145k ive religously serviced it it sounds and pulls good

[motchy87]

Just wondering...it may be the type of fuel you are putting into your cars. Avoid supermarket fuel - treat yourself to BP or Shell diesel for example and see if there is a difference. When I was looking to buy an Audi 80 tdi, the seller said he bought it with a 'juddering' problem but once he changed to better fuel, the problem went away. Just a thought that's all...

[treb0r]

Hello again. There's a guy I work with has the same car, but without the judder! I figure if the ECU is causing the judder from the VSS signal I could try swapping them over to see if that fixes it. Anyone know where the box is located and if it's possible to unplug easily?

[micheal balbrig]

Hello Trebor

The ecu is situated behind carpet in passenger footwell
accessed by removing glove box it is easy to swop around

P.S. I done this swop previously with no results

The problem was in the electronic throttle unit on injection pump

Maybe your work mate might swop injection pump temporarily !

[audijay73]

[quote=motchy87;140000]Thanks for the reply i will try i have been messing around with actuator setings the judder is still there only slightly i thought of trying bio diesel my mate makes it himself he is pretty clued up on the process but before i do i will try bp or shell next time i fill up will let you know cheers jay