intermittent working speedo on 75 2.0TS
Posted: Mon Feb 14, 2005 12:11 am
i'm at my wits end, and i hope gurus here can help.
driving a 75 2.0TS and have been having this weird problem with the speedo. i'll describe the problem.
when the car is moving on a highway at a relatively constant speed, under very hot ambient conditions, after some time the speedo will start to go haywire, where under slight pressing of the accelerator the speedo will drop speed, and if u release the accelerator it will seem to jump back to the proper speed again. if u keep accelerating the speedo will go down again and will even drop straight down to 0. even when u try to just drive at a constant speed when the trouble happen, pretty soon the speedo needle would just drop back to 0 and will stay there. however, if u stop the car (engine still running), and drive back up again, speedo will work again but not for long (1 - 2 minutes).
the funny thing is, this only happens when ambient temperature is hot and car has been driven in such condition for 20 minutes or so.
instrument panel has been checked, and doesn't seem to be a prob. i've taken out the speedo signal amplifier (under the rear seat) and even solder the joints (they were fine, but i just want to be sure). also cleaned the connectors. secured all the cables and amplifier so that they don't move under the seat.
the only thing left is the actual sensor at the gearbox. is it possible to dismantle that and see what's wrong? it seems to be heat related somehow, and i worry it might be connections at the sensor expanding too much thus loosing connectivity when the temperature is too high. but that's just a guess.
any hints and help is apprecieated. thanks!
driving a 75 2.0TS and have been having this weird problem with the speedo. i'll describe the problem.
when the car is moving on a highway at a relatively constant speed, under very hot ambient conditions, after some time the speedo will start to go haywire, where under slight pressing of the accelerator the speedo will drop speed, and if u release the accelerator it will seem to jump back to the proper speed again. if u keep accelerating the speedo will go down again and will even drop straight down to 0. even when u try to just drive at a constant speed when the trouble happen, pretty soon the speedo needle would just drop back to 0 and will stay there. however, if u stop the car (engine still running), and drive back up again, speedo will work again but not for long (1 - 2 minutes).
the funny thing is, this only happens when ambient temperature is hot and car has been driven in such condition for 20 minutes or so.
instrument panel has been checked, and doesn't seem to be a prob. i've taken out the speedo signal amplifier (under the rear seat) and even solder the joints (they were fine, but i just want to be sure). also cleaned the connectors. secured all the cables and amplifier so that they don't move under the seat.
the only thing left is the actual sensor at the gearbox. is it possible to dismantle that and see what's wrong? it seems to be heat related somehow, and i worry it might be connections at the sensor expanding too much thus loosing connectivity when the temperature is too high. but that's just a guess.
any hints and help is apprecieated. thanks!