problem with 96 Jetta GLS

Hi David, My Bentley manual for a '90 Golf reads as follows (should be similar for a Jetta). See the part about the O2 sensor as it could be implicated. Also it depends if your car was sold into the Canadian or the US market. I quote liberally...

"The speedometer cable runs from a drive gear in the transmission to the back of the speedometer. On automatic transmissions, the cable is mounted directly to the transmission with a union bolt. On manual transmissions, the speedo cable is held by a bolt and hold-down clamp to the tranny and separate drive gear as shown in Fig 4-13 (if needed I can send you a scanned image). On US and Canada cars with O2 sensors, the cable is in two pieces. The first part runs from the transmission to the O2 sensor mileage counter mounted on the firewall. The second part runs from the O2 counter to the speedometer. On diesel cars and Canada cars with auto transmissions, the speedo cable is in one piece".

So I would suggest checking for any forgotten connections around the O2 sensor. It would be a coincidence, but it could also be that one of the 2 cables might have been bent and broken during the O2 change.

Regarding what is driving the tach, I suspect it gets an electrical signal off the coil and is not mechanically driven at all. Just a guess.

-Tony

-------------------- twong(at)vcn.bc.ca Vancouver, BC Canada

Good suggestion, but a 90 VW is not the same as a 96 Jetta. All 96 Jetta's use an electronic speedo and have no cable! I'm heading for work and will replay later.

Thanks for the clarification. Sorry David, I don't have any more suggestions other than re-check the connections between the speedo sensor and the speedometer.

-T>Good suggestion, but a 90 VW is not the same as a 96 Jetta. All 96 Jetta's

-------------------- twong(at)vcn.bc.ca Vancouver, BC Canada

My parents 94 Jetta has the same issue so will be doing diagnosis starting next week. Will let you know what I checked, and how, and what I find.