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Mad_Bohemian

Speedometer (not odometer) problems..

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I don't recall ever seeing this problem addressed here, I did a search which produced no results...

Due to a series of car problems, motor blew on my daily driver and my white TC blew a brake line near the rear section of the frame, I have had to press my burgundy TC into daily service (ouch). Yesterday after my wife came home from work (about a 7 mile drive) we left to have dinner with some friends. Got onto the highway and noticed the speedometer wasn't working. The odometer was working fine though. Drove about 4 miles and stopped at a gas station. When we left the speedometer was now working...

Later when left to go home it started acting up again. This time, however, it would sit at zero, then jump up to 65 (we were on the highway) it would waver there for a 5-10 seconds then drop to zero for 10-20 seconds...then pop up again. After about 3-4 miles of this it stayed at 65 with a 2 mph waver from side to side. After about 10 miles it settled down and held steady and worked fine the rest of the way home.

Looking through the service manual, I am leaning toward a faulty distance sensor..? The manual refers to a "Powertrain Diagnostics Test Procedure Manual" to test the "sensor and related components". Never heard of this manual... :confused: Or would the problem be in the speedometer itself? Has anyone else ever had similar issues with an 89. 4cyl turbo automatic

TIA

Brian

Edited by Mad_Bohemian (see edit history)

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Benefits of AACA Membership.

Usually when the Speed Distance Sensor goes bad you can tell by slowly rolling to a stop with the clutch in (err, I mean by shifting to nuetral:D) Among other things the SDS keeps the 'idle' at about 1500 RPMS to prevent stalling until under about 5MPH. So get going 20MPH or so, shift to neutral, and roll slowly to a stop. Idle should be 1500 until just when you drop to under 5MPH. If it does that, the SDS is working. Having said that, they do tend to fill with grease/oil because of the low position on the transmission. So you might try disconnecting the plug and cleaning the connections with contact cleaner. Careful, the catch is brittle, peel it back only SLIGHTLY. If you do break it, it will still stay plugged in because its a vertical connection:o

Alan

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Hi Folks, the Bohemian is back after  (what appears to be ) a 6 year hiatus....life got busy, spent some time rebuilding the brake and fuel line on the 90 TC, got busy with my motorcycle modifications and customizing. Then we sold our house two years ago, built a new home while living in a 2 bdrm apt with our two Border collies. Moved in to the house last December and have spent the last eight months on finishing some of the basement, landscaping and building a pole barn. FINALLY getting around to working on the 89 TC and this speedo problem. 

Checked the distance sensor, not much going on in the way of grease/oil. Pulled  and reset the plug, no help, still no speedo. Pulled the speedo and checked for voltage on the pins - checks good, so I'm down to checking the continuity of the distance sensor cable and then trying to figure out what the  "Powertrain Diagnostics Test Procedure" is....So two questions...

 

1) Can anyone help with which pin on the transaxle end of the distance sensor cable I should check with the pin on the speedo cluster?

2) Do anyone know how to test if the speed sensor is bad...??

Thanks guys.....It's good to be back :D

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Spend the $32. on a new one from RockAuto, install, save yourself the whole 'testing' process;)

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Check the solder connections on the PCB that the speedo connects to. Over time the joints can crack leading to intermittent electrical issues with gauges.

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Am I correct in assuming that when I replace the distance sensor I should place the speedometer pinion in to ensure the gears mesh/align, then put the new sensor in. Or Should I put the sensor and pinion in as a unit?

Edited by Mad_Bohemian (see edit history)

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It goes in as a unit, assemble your old gear onto the new SDS and drop it in. I too took a few years 'off from cars', the first time when the kids were small and needed my time and the second time during the divorce years when I needed theirs:wub: 

 

 

 

 

life does get in the way but fortunately TCs are like old friends, they wait until your ready to interact with them  again.  You should consider all new fluids after a six year hiatus...

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Replaced the distance sensor, verified power to the speedo (again) and continuity from the sensor plug to the pin on the dash as well as the ground wire from the sensor plug...all checks good Made sure I had good contact on the 3 pins into back of the speedometer cluster and still no speedometer... :angry:

Do I have to replace the speedometer itself?! A quick search of the world wide web shows nada for such a beast.  <_<

On 8/16/2017 at 2:46 PM, Reaper1 said:

Check the solder connections on the PCB that the speedo connects to. Over time the joints can crack leading to intermittent electrical issues with gauges.

 

All connections look solid upon close inspection...

 

Edited by Mad_Bohemian (see edit history)

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It's not common for the speedo head itself to go bad in these. Usually it's just the odo gears. That's not to say it can't happen. There are placed that specialize in speedometer repair. You could try to pop in another head to see if it works, and then if it does, you could either leave that head in there, or send yours out to be repaired.

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You can use a speedometer from a Daytona to test with as well although the backlit color is blue rather than red an in the TC speedometer.

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4 hours ago, Reaper1 said:

It's not common for the speedo head itself to go bad in these. Usually it's just the odo gears. That's not to say it can't happen. There are placed that specialize in speedometer repair. You could try to pop in another head to see if it works, and then if it does, you could either leave that head in there, or send yours out to be repaired.

 

4 hours ago, Hemi Dude said:

You can use a speedometer from a Daytona to test with as well although the backlit color is blue rather than red an in the TC speedometer.

 

Thanks for the replies. Any leads on where I can find a replacement head from a TC (preferably) or a Daytona??

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Having a biotch of a time getting replies from repair shops  (even TC parts) on whether or not they can work on this speedometer...

 

Hemi Dude, is there a particular year Daytona speedometer head to use?? Cross reference data on Ebay says no fit ( although I trust your judgement more than Ebay!  :D )

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13 hours ago, Mad_Bohemian said:

Having a biotch of a time getting replies from repair shops  (even TC parts) on whether or not they can work on this speedometer...

 

Hemi Dude, is there a particular year Daytona speedometer head to use?? Cross reference data on Ebay says no fit ( although I trust your judgement more than Ebay!  :D )

One of the same 80's era.  Not any from the 90's as far as I know. 

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Any LeBaron or Daytona speedometer head from 1985-1989 should plug in an work in the TC cluster.

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IT WORKS!! :D Found a replacement dash for cheap. The odometer gear was broken so while swapping out the good gear from my original speedo, I swapped out the odometer as well so my car still has the original odometer and correct miles :D thanks  for the help Digger914 with the leads for junkyards with parts!!

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