A4 1.8 speedo problems

[Jonny_doe]

Hello great forum here ..

I had my car for just over a year , it's a 1.8 a4

It's been fine up until yesterday , anyway yesterday i went to drive it and the speedo just wasn't working , i had to drive about 150 miles on the motorway so i was abit annoyed , but after about 5 minutes it just kicked back into life , great !!!
now this morning i went to drive it and the speedo was not working again , and i noticed the fuel dial is also jumping up and down , and way i drove almost alday and everything still the same ... (No speedo , and Fuel dial acting up ).

Has anyone got any ideas ???? the cars working fine apart from these fualts ..

thanks for any replies /ubbthreads/images/graemlins/wink.gif

 

[ajmackie]

ok. it is not a mechanical cable, it is an electrical sinal. there is a transducer somewhere along the drive shaft, ie wheel or gearbox. could well be that, maybe a loose connection. You need to find out how the sinal from the transducer is distributed. It might go into the ECU (car computer) and then split to aircon display and speedo?

Best thing is prob to take it to a audi garage or independant audi garage. when there is a fault, the ecu normally stores it and they can then read if there are any faults and diagnose the problem. it does sound to me as though there is a loose connection, especially with the fuel gauge messing up.

 

[Jonny_doe]

Ok AJMackie , thank you for your help , i'll get the car up on the ramps this weekend and take alook /ubbthreads/images/graemlins/wink.gif

 

[ajmackie]

no probs. good luck.

 

[Jonny_doe]

ok , i've disconnected the dashboard , cleaned connections and replaced ,
jacked the car up and disconnected the connections on the gear box , sprayed them with wd40 and reconnected , went around every wheel and disconnected and cleaned up the speed sensors , and reconnected .. i then drive around the block and every thing was still the same , i.e. no speedo or milage ... So i gave up , packed everything away , washed up and went over to my mates house , which is 1 junction of the motorway away, now when i joined the motorway and got to about 80 mph the speedo jumped back into life , and was fine for the rest of the day , so am now well lost as to what it is ... Any ideas ???

 

[ajmackie]

i reckon u've done a lot of work to avoid a trip to audi, but u need to know the speedo system as it might be a sensor elsewhere!? I would ring up a specialist as they might have had the problem before.

 

[ajmackie]

also the sensor could be bust, altough i doubt it as i think they just tx and rx a magnetic field.

 

[Jonny_doe]

the speedo's not working again today , does anyone think it might be a bad earth ???

 

[fireblade]

Wish i could help, but i'm as stuck for ideas as you.
Mines been ok for the last couple of weeks but who knows for how long.
There was a lad on an American site i found with the same problem but he hasn't posted back to say if he ever got it fixed.

Good luck

Jim