Audi 80 tdi juddering bucking jerking

[markfq300]

hi, i have an audi 80 tdi which had the same problem under load at higher speed, this reported a code of 00575 back on diagnostics, which ended up being the sensor on the intake to the turbo, this is the one with a plug on the underside with a red pipe that goes under to the turbo and there are two other small diameter pipes on it as well. genuine part was 36quid plus the tonic.

hope this advice is some help to you.
mark

[allan_audi]

hi, i have an audi 80 tdi which had the same problem under load at higher speed, this reported a code of 00575 back on diagnostics, which ended up being the sensor on the intake to the turbo, this is the one with a plug on the underside with a red pipe that goes under to the turbo and there are two other small diameter pipes on it as well. genuine part was 36quid plus the tonic.

hope this advice is some help to you.
mark

Sounds like the N75 Boost control Valve, which I've replaced with no effect, has three vacuum/pressure type pipes to it and an electrical connector. I've never seen any fault codes present with VAGCOM connected, only when I intentionally removed the air flow meter connector just for sanity!!

The intermittant misfire I still get, I'm really stumped as to what it is, but still thinking it might be lift pump or fuel injection relay.

[midskev]

well chaps its wit regret i tell u shes failed the mot and has been layed to rest well on ebay acctualy with all the ongong probs and the mot repairs i thorgh better of it i will miss the old girl had 7 years of fun and iv done 90k in her never let me down once,
hope u all sort out the ongong prob and i will be poping vack to keep up with events
my girlfriend has brought me a new volvo so i will pass judjment later on that

hope u all keep well n happy motoring its my 7th audi

kevin

[treb0r]

Hi - I bought my Audi 80 Est 1.9 tdi in Jan, with this same fault present. Previous genuine owner said it had been doing this juddering at idle and part throttle for the past 2 years. Annoying but never got worse or better. My local garage replaced the mass air flow sensor - no change, then took it to diesel specialist. £150 later, they said the diaphragm in diesel pump was culprit. Labour costs to strip and refit were prohibitive. Better spending £700 on a new pump and fitting. So I bought one off ebay from a Galaxy - £70. Will change the wiring over this weekend and let you know if it's any better.

[treb0r]

Decided aginst swapping pump over - the wiring is welded inside the pump, so to swap it over I'd have to retain half the internals on the old pump, which are probably the culprit anyway. Looking for one off another Audi. Incidentally, I appear to have 2 distinct issues. The pump is probably responsible for the chugging at idle, but the VSS is definitely responsible for the juddering at part revs. My speedo has been working intermittently, and every time it works the juddering is evident. Whenever it packs up again it's fine. I'll have a go at cutting that wire behind the dash. Got another gearbox en-route too but that's another story.

[atc]

I had this problem, cleaned the injectors in an ultrasonic bath with spirit. Worked a treat. The problem with this question is that there could be several route-causes. I diagnosed my particular issue by setting the injection pump and getting the wrong volume of diesel being delivered!

Hope this helps

A

[del649]

Hi All, This is not a problem that I am suffering with (and hope i dont) but couldnt help reading all the usefull replies.I have not studied the wiring on my car much, but i know some vehicles have a voltage regulator in the dashboard which may be faulty or dry jointed causing confusing signals to be generated and sent to the ECU, thereby causing fuelling mismatch.

I could of course be talking rubbish, but its another avenue to look at.

Del

[steve_ball]

Well, my first post was entitled "My 1995 N TDI has rough shuddering / missing 1200-2000 rpm"... and a little research :-) has brought me here... so I guess I'm a member of the juddering / jerking / shuddering / shaking club too!!

Having read through all the posts, seems it's quite a common issue, and that the VSS connection the most likely fix. Well I check it out, and report back anyway...

Just one question - and yes, I did read though all 13 pages - is whether this juddering does any long-term damage to the car... or in other words, are there good folks here who've put up with juddering for many thousands of miles... ? If the juddering is just annoying but not very damaging, I can certainl live with it....

[allan_audi]

Well, my first post was entitled "My 1995 N TDI has rough shuddering / missing 1200-2000 rpm"... and a little research :-) has brought me here... so I guess I'm a member of the juddering / jerking / shuddering / shaking club too!!

Having read through all the posts, seems it's quite a common issue, and that the VSS connection the most likely fix. Well I check it out, and report back anyway...

Just one question - and yes, I did read though all 13 pages - is whether this juddering does any long-term damage to the car... or in other words, are there good folks here who've put up with juddering for many thousands of miles... ? If the juddering is just annoying but not very damaging, I can certainl live with it....

Welcome to the club!!!!

I've had my TDI for under a year, but I'm doing 35k a year, so far covered 20k with the VSS mod and no problems. I have no doubt that the judder/jerking does damage, it has to damge suspension bushes, engine mounts etc, but it doesn't seem to do any major damage to anything. They do seem to go on for miles anyway, my Avant TDI has done 141k and it seems some of the people here have seen 200k+ I have no idea how long mine had been doing the jerking, who knows, probably thousands of miles.

My personal opinion is that I couldn't put up with it, and the VSS mod gets around it. Only slight problem especially in cold weather is you lose the glow plug light (also CEL), but its not really that much of a problem.

Its certainly worth trying the VSS mod, cut the wire behind the dash, remove the CEL (as in previous post). I'm still determined to get a closer look at this with an oscilloscope, I just haven't had time and the car drives much better anyway.......

I'm convinced the root problem is the gearbox/drivetrain (excessive play) and if/when the clutch goes I'll take the drive flanges off and take a closer look. They're an odd layout with FWD in-line engine/gearbox, I've not heard this reported on any VWs with the same engines. They use FWD transverse engine/gearbox. ie. VWs use the same engine (including electronics) but with a different gearbox. The layout on the Audi seems to be asking for problems, especially if you look at the engine pivot points (as it tries to turn on its mounts).

Also bear in mind that I think there are various problems discussed on this forum, ie. various manifestations of jerking/judder. The VSS mod will stop the cyclic judder, the one that seems to want to shake the car to bits, and doesn't stop until you drop the clutch or back off the throttle.

Anyway, let us know how it goes, any info is always helpful!!

[diego666]

Hi there studder sufferers,

I'm new to this long thread and happy to stumble upon it- I too have this incessant studder/violent jerking once the car is warmed up. I'm at a loss after replacing and cleaning many potentially culpable parts around the motor to no real benefit.

So after reading all 13 pages with interest, this VSS sounds like the key to the symptom. I opened the panel under the dash (I'm in mainland Eur so LHD) and it's a hopeless mess of wires, plugs-some connected, fuses, relays...don't even see a 109 anywhere, but my car's an odd story.

Anyway, would one of you describe which is the VSS, what it looks like/is connected to? I really don't want to find myself cutting the wrong wire!

diego


PS: thanks to all of you for digging through this issue