Audi 80 tdi juddering bucking jerking

[arderra]

I don't know what others think, but the way I read it, the inj pump swarf seems to be the most common issue. Unplugging the speed sensor or pulling the fuse for the instruments has the same effect as cutting the blue/white wire. If the car is improved and you are happy with the throttle response you could get away with cutting the blue/white wire.
Doing this does not solve the problem, but it does mask the issue?
The full pump repair appears fairly straightforward, but probably not for the faint hearted?
The no.3 injector issue is another one that can cause running problems, but i think it will give a fault code? If you choose to change all injectors I would consider ones from the AFN 110 hp engine, you will get a bit more bang for your buck!

Hi scotty,
thanks for the reply. Will tackle the injector pump tomorrow. Sure, how hard can it be!!!! Don't really fancy cutting wires.

Will let you know how I get on.

[touranasurus]

HI, had this years ago, both driveshaft CV joints where shot, worth a look. What about "crank-sensor"- good luck.

[arderra]

HI, had this years ago, both driveshaft CV joints where shot, worth a look. What about "crank-sensor"- good luck.

,

Hope everyone had a safe Christmas

Hi touranasurus
thanks for the pointers. I do know that a lot of the bushes etc are worn and replacements ordered.
what I did do yesterday ( in fading light and rain!!) was to "take a look" at the injector pump!! ( I know, I know :-( ). So, opened it up carefully as not to dislodge anything, couldn't find a way of getting into the coil (where the swarf builds up) and decided to close it all up. Managed to get the "pin and hole" to line up ( don't think it will close otherwise!). Tried to start it but no joy :-(. She will turn on the starter but that's it. I checked the injectors and they are getting fuel. I did read on another post that the cover needs to be adjusted to allow it to fire up. At the moment it is "set" forwards, nearest to the engine. I will have to slowly push it back towards the fire wall and hope it works!!!

on another point, can I simply lift an injector pump straight out of an 93 car and place into a 94 WITHOUT adjusting anything or setting it up (timing etc)

you may have guessed by now, I'm not a mechanic so don't have any specialist equipment
cheers
A

[touranasurus]

HI, from my experience you have to get a pump that has the same "batch" number on it or it will not work correctly. have you tried the chemical route, there is some good fuel additives about, would clean your system out, injectors would benifit. the one i use is "diesel magic" -it does work ?

[micheal balbrig]

,

Hope everyone had a safe Christmas

Hi touranasurus
thanks for the pointers. I do know that a lot of the bushes etc are worn and replacements ordered.
what I did do yesterday ( in fading light and rain!!) was to "take a look" at the injector pump!! ( I know, I know :-( ). So, opened it up carefully as not to dislodge anything, couldn't find a way of getting into the coil (where the swarf builds up) and decided to close it all up. Managed to get the "pin and hole" to line up ( don't think it will close otherwise!). Tried to start it but no joy :-(. She will turn on the starter but that's it. I checked the injectors and they are getting fuel. I did read on another post that the cover needs to be adjusted to allow it to fire up. At the moment it is "set" forwards, nearest to the engine. I will have to slowly push it back towards the fire wall and hope it works!!!

on another point, can I simply lift an injector pump straight out of an 93 car and place into a 94 WITHOUT adjusting anything or setting it up (timing etc)

you may have guessed by now, I'm not a mechanic so don't have any specialist equipment
cheers
A

If its any help, as far as I know the top unit on pump, the one you removed has different electrical system to the 93 model. from memory the visual difference was that the 93 one had a pipe emerging from the top of lid. The 94 pipe emerged from end facing windscreen.
When starting initially, be ready to kill engine in gear in case of run away.
sometimes body can be cleaned by spraying carb cleaner in and using compressed air to try to remove the fine swarf.
Regards
Micheal

[arderra]

Hi Michael,
you are correct about the injector pump (externally). Don't know about internally ( don't want to mess up another one )
I assume what you mean by stopping it in gear is - if the engine races, put on handbrake, out her into 5th and, while pressing on the brake pedal let out the clutch ( to stall the engine). Correct?

Hopefully, it won't come to that!!
Away from the car for a few days. Will let you know if its purring or screaming later

cheers
A

[arderra]

HI, from my experience you have to get a pump that has the same "batch" number on it or it will not work correctly. have you tried the chemical route, there is some good fuel additives about, would clean your system out, injectors would benifit. the one i use is "diesel magic" -it does work ?

Hi touranasurus,
didn't try any chemicals yet. Haven't cleaned out the pump coil either ( couldn't access it without removing a potentiometer (I think!!). It looked too complicated for my hammer and vice grips!! Lol.
When I get her running ill try the diesel magic.
If all else fails ill bring both injector pumps to the specialist and see what he says. I would like to change to the 93 one as it appears the 94 car was in a bit if a crash. All the pump fixing lugs are broken or cracked!!
Regards, arderra

[arderra]

Managed to sort out the pump (without cleaning it!!) But at least shes running (and still juddering) Will mark everything up again and then retackle when the weather improves.

Dont know if I mentioned that the vents were not blowing very well. I pulled out the glove box and stuck my head in as far as I could. Turned on the blower to full and found a 20mm gap between the ducts. Looks like the dash will have to come out to be able to refit the connections :-(

[ross b]

Cant believe i havent noticed this thread earlier, mine suffers from the same problem which i have been puzzled over for years. Id like to try cutting the vss wire but when i removed the plug this evening noticed two blue + white wires? One is mostly blue with a white stripe, the other is white with a blue stripe. im reluctant to just go cutting wires randomly so can anyone point me in the right direction? thanks ross

[ross b]

Can anyone help on this one? Ive drove the car with the dash removed ie the speedo clocks unplugged and removed, should this have the same affect as cutting the VSS wire? ive not noticed a difference. help !