Birty Dastards Jeep Club

Tech Forum => Workshop => Topic started by: ivanidea on October 04, 2005, 04:47:57 PM

Title: TJ speedo and oddometer not working
Post by: ivanidea on October 04, 2005, 04:47:57 PM

Returning from Cheapfest, my speedo stopped working and the odometer has frozen.  All other gauges are working.

I can't blame Ribbesford, since I didn't take the Jeep off-road due to absence of front prop shaft.

Any ideas?

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Post by: Anonymous on October 04, 2005, 04:50:35 PM

It's still a cable on a TJ I think..... guess the cable has Broked'ed

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Post by: isle of man on October 04, 2005, 05:12:50 PM

i do not think it is a cable...

peter henry

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Post by: Mike Pavelin on October 04, 2005, 05:58:26 PM

Check the speed sensor on the rear of the transfer case. This drives the speedo.

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Post by: Woody on October 04, 2005, 10:37:45 PM

No the speedo on a TJ is electronic.  Interesting after having regeared my speedo to match my diffs it has a 10-15% over reading error vs GPS, last time I was over at MDG we tried out Mark's new diagnostic computer on a test run of the TJ.  The EMU was receiving the speed signal with only a 1mph error at 60 vs GPS, the system then appears to add the over read error before sending it to the speedo.  The Odometer reads correctly though.

Woody

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Post by: Bubba on October 05, 2005, 06:08:40 AM

to much info brain hurts ...try rotating the speedsensor slightly in the gearbox it may do the trick or take it out and clean it

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Post by: ivanidea on October 05, 2005, 12:25:33 PM

Thanks for the info, I shall try and have a look at the weekend.

Ivan

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Post by: Anonymous on October 05, 2005, 12:44:19 PM

Quote from: "Mike Pavelin"

Check the speed sensor on the rear of the transfer case. This drives the speedo.

Only Jeep could fit a cog on the end of a sensor  

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Post by: Mike Pavelin on October 05, 2005, 03:03:37 PM

It's because the transfer case was originally designed to drive a conventional speedo cable. The upside is that you can easily recalibrate the speedo by changing the size of the gear on the sensor.

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Post by: teamwrangler on October 05, 2005, 08:54:20 PM

Get the same problem with my TJ, hiting the top usually fixes it!!!

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Post by: Mike Pavelin on October 06, 2005, 08:30:24 AM

There's a TSB about that, cluster dies and airbag light comes on. Official fix is to clean connectors on cluster and replace one of the plugs.

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Post by: ivanidea on October 09, 2005, 04:15:52 PM

Took the speed sensor out, even though I couldn't disconnect the wires as per the instructions from the service manual.

The gear is just a pile of plastic, not a tooth left on it.

I presume Lighthouse should be my first port of call, but I don't know what replacement gear to order for 33" tyres and 4.56 gears.  Any recommendations appreciated.

Many thanks,

Ivan

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Post by: Woody on October 09, 2005, 05:34:48 PM

Ivan

if Lighthouse don't have any in stock, try Mark at OffroadMDG he occasionaly has them on the shelf.

My speedo died during a shopping trip yesterday but a quick wiggle on the plug for the transducer on the transfer case and it was back

Woody

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Post by: Mike Pavelin on October 09, 2005, 06:37:25 PM

39 teeth.

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Post by: ivanidea on October 09, 2005, 07:44:20 PM

Many thanks Mike.

Do I have to do anything special to try and clean the bits of plastic from inside the speed sensor gear housing?  It is in an awkward position to clean (just like most Jeep parts)?  

Do I need to any oil / lubrication? Or does the oil seep through from the transfer case?

Is there a knack to disconnecting the wiring clip? The red slider is broken at one end on mine.  Off topic - how do I unclip the rear fog light wiring?  I had to cut the cable and will need to hardwire into the replacement unit I have, but would like to know for next time.

Ivan

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Post by: Anonymous on October 09, 2005, 10:02:56 PM

OE rear fog wiring was behind rear bumper if thats any help

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Post by: ivanidea on October 16, 2005, 06:57:13 PM

Spent 2 days working on my Jeep, and still the speedo won't work.  I can not remove the wiring connector, it is well and trully stuck. According to the service manual, the 30-45 marking should be at the 6 oclock position, so I installed the unit with this set of numbers at the bottom.

Any further advice would be appreciated, or it may mean an expensive dealer service.

At least I managed to replace the diff and transfer case fluids and install my replacement rear bumper, so not entirely a wasted weekend.

Next I'l be changing the oil!  (Maybe next year).

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Post by: Bubba on October 16, 2005, 09:48:07 PM

wel done mate small steps at a time