A80Q mileo dead??

[spaarky]

1988 80quattro (1781FI - DZ engine) has been my daily for 12 years now & has treated me real good, but due to redundancy, subsequent lack of funds & my ignorance, is now feeling its age in a few areas

oddest problem I've noticed today is that the mileometer & trip meter have stopped working - speed needle still works ok (except when is sticks in the winter, but that's another story), but the mileage don't change, regardless of how far you drive - same for the trip meter - is that even legal ..?

in an older car, I woulda thought the speedo cable had snapped since I have had some screeching noise from front end over last few weeks, but speed needle is still working fine

have looked at haynes manual - as most of you know, they don't do a manual for the quattro - and the wiring diagram (for 2.3 -7A engine models, whereas mine is 1.8 DZ engine) suggests an electronic speedo sender, but can't find any info anywhere about what drives the mileage & trip. haynes about as much use as tits on a fish, as usual

anyone got any experience/ideas ? am I being a dummy & missing something obvious ? sadly can't afford to replace parts unless absolutely sure to fix. any thoughts much appreciated

[spaarky]

apologies if the above is posted in the wrong forum, but can't see how to move, or even which other forum would be more appropriate since not sure if a mech or elec prob

[Puglife]

Firstly what shape is the 80 quattro? i'm guessing at type85, in which case it will most likely be electrical speedo sender. This is on the side of the gearbox diff casing (from memory its just above the passenger side driveshaft output flange.)

IT could also be a problem within the instrument cluster where speedo sender is giving a reading from diff worm drive, but the tripmeter isnt picking up the signal for distance..

[Ben]

If the speedo is still working then the sender is too, I had a speedo to pieces a few weeks ago and it's a self contained unit with the milometer driven from a stepper motor. I'd suspect a soldered joint has become dry inside the speedo unit, if you have a soldering iron then you can run it over any suspect joints, if you want to replace just the speedo unit then beware as Audi have different versions of the binnacle and the innards aren't interchangable.

[spaarky]

many thanks ben & puglife - has bin a real struggle to get any info on the car or a decent workshop manual & the haynes one is almost a total waste of space. web don't seem to be much help either so far

it's a B3/Typ89 A80 body with a small boot spoiler & quattro - not sure if it's relatively unusual or if they didn't last long, but I've only ever seen one other similar on the road in 12 years & that was a quick glimpse a coupla weeks ago. I have bin lookin - this is my second audi & my old man is on his 5th since the late 70s. if it's unusual, that's probly why I can't find any info anywhere

I thought the same as ben - if there's only one sender for all speedo functions, and the speed needle works, then presumably the sender is good & it must be a problem with the mileage function in the speedo unit, but am just guessing. is it common for solder joints to dry out/break contact after a few years ? I can solder no prob, but can't afford to get another complete speedo unit, especially if main dealer is the only source - don't even wanna think how much that might cost, or even if they are still available

if mileage is driven by a stepper motor inside the speedo, do you think it possible that a 2nd hand stepper motor might fix it if available somewhere (?), or is it a case of trying the solder and if that don't work, next step is a whole new speedo unit ? sorry for all the questions, am looking for cheap straws to grasp

many thanks for your help, any & all advice much appreciated

[Puglife]

I have a speedo unit from an Audi 90 type 89 here. I'm not that up on the type89 layout but i can certainly get some photos of the innards for you if its any help?