Speedometer gauge intermittently dropping: Please help me fix my Speedo!
#102
Greg
Last edited by Greg in France; 01-17-2017 at 02:47 AM.
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orangeblossom (01-17-2017),
paulyling (01-17-2017)
#103
Well guys, I swapped out the Speedo Transducer...but didn't fix the problem.
It was easy enough. Just un-plugged and un-bolted. No goo gushing out.
Placed the new sensor in and gave her a test drive. Still dead. Bugga.
Can anybody tell me if this wiring goes back to the engine bay or does it go straight inside the cabin to the gauge cluster harness? Maybe I have a loose wire somewhere?
The reason I say that is I now have a new transducer and the speedo gauge isn't that old as it was re-conditioned with new PCB by an instrument specialist that is local.
The only saving grace is it probably wasn't a complete waste of time. My speedo, since getting it re-conditioned, never activated until the first gear change. As Greg pointed out this is probably due to a dodgy transducer. So when I finally get the needle going again, I reckon it should work as soon as I take off.
I was also going to pull out the instrument cluster tomorrow and have a bit of a once over but I think it will be fine.
Any other ideas?
The old transducer in situ
With the old transducer pulled off. What remains is a little yellow plug.
New transducer installed. Easiest job I have done in a while!
Tied back the wiring so it is out of the way:
It was easy enough. Just un-plugged and un-bolted. No goo gushing out.
Placed the new sensor in and gave her a test drive. Still dead. Bugga.
Can anybody tell me if this wiring goes back to the engine bay or does it go straight inside the cabin to the gauge cluster harness? Maybe I have a loose wire somewhere?
The reason I say that is I now have a new transducer and the speedo gauge isn't that old as it was re-conditioned with new PCB by an instrument specialist that is local.
The only saving grace is it probably wasn't a complete waste of time. My speedo, since getting it re-conditioned, never activated until the first gear change. As Greg pointed out this is probably due to a dodgy transducer. So when I finally get the needle going again, I reckon it should work as soon as I take off.
I was also going to pull out the instrument cluster tomorrow and have a bit of a once over but I think it will be fine.
Any other ideas?
The old transducer in situ
With the old transducer pulled off. What remains is a little yellow plug.
New transducer installed. Easiest job I have done in a while!
Tied back the wiring so it is out of the way:
The following 2 users liked this post by paulyling:
Greg in France (01-18-2017),
orangeblossom (01-17-2017)
#104
It sounds like you did not remove the driven unit??????
That driven unit has a nylon gear that meshes with the drive worm on the trans mainshaft.
That nylon gear can loose its teeth, and hence NO drive.
The trans governor, on the other side, and driven by the same worm gear also can loose its teeth, and the trans stops shifting.
The speedo driven gear is a GM item, and colour related, soooo, if it is the issue, take it to any half decent transmission repair mob, and get one the same colour.
Failing that, look at the trip computer, and note if it is changing ANY numbers after a 10km run, it is IS, then the transducer and adaptor ARE working. It its the same as when you left home, then that gear is suspect.
BUT.
The Yellow wire that goes through that grommet in the tunnel, splits off somewhere near the console front lip, near the whole bunch of wires for the climate system. 1 wire goes to speedo, 1 wire goes the trip computer, 1 wire goes to the cruise control, and they are British, and I have had 2 cars with that split broken, so maybe.
That driven unit has a nylon gear that meshes with the drive worm on the trans mainshaft.
That nylon gear can loose its teeth, and hence NO drive.
The trans governor, on the other side, and driven by the same worm gear also can loose its teeth, and the trans stops shifting.
The speedo driven gear is a GM item, and colour related, soooo, if it is the issue, take it to any half decent transmission repair mob, and get one the same colour.
Failing that, look at the trip computer, and note if it is changing ANY numbers after a 10km run, it is IS, then the transducer and adaptor ARE working. It its the same as when you left home, then that gear is suspect.
BUT.
The Yellow wire that goes through that grommet in the tunnel, splits off somewhere near the console front lip, near the whole bunch of wires for the climate system. 1 wire goes to speedo, 1 wire goes the trip computer, 1 wire goes to the cruise control, and they are British, and I have had 2 cars with that split broken, so maybe.
Last edited by Grant Francis; 01-17-2017 at 04:18 AM.
The following 3 users liked this post by Grant Francis:
#105
It sounds like you did not remove the driven unit??????
That driven unit has a nylon gear that meshes with the drive worm on the trans mainshaft.
That nylon gear can loose its teeth, and hence NO drive.
The trans governor, on the other side, and driven by the same worm gear also can loose its teeth, and the trans stops shifting.
The speedo driven gear is a GM item, and colour related, soooo, if it is the issue, take it to any half decent transmission repair mob, and get one the same colour.
Failing that, look at the trip computer, and note if it is changing ANY numbers after a 10km run, it is IS< then the transducer and adaptor ARE working. It its the same as when yo left home, then that gear is suspect.
BUT.
The Yellow wire that goes through that grommet in the tunnel, splits off somewhere near the console front lip, near the whole bunch of wires for the climate system. 1 wire goes to speedo, 1 wire goes the trip computer, 1 wire goes to the cruise control, and they are British, and I have had 2 with that split broken, so maybe.
That driven unit has a nylon gear that meshes with the drive worm on the trans mainshaft.
That nylon gear can loose its teeth, and hence NO drive.
The trans governor, on the other side, and driven by the same worm gear also can loose its teeth, and the trans stops shifting.
The speedo driven gear is a GM item, and colour related, soooo, if it is the issue, take it to any half decent transmission repair mob, and get one the same colour.
Failing that, look at the trip computer, and note if it is changing ANY numbers after a 10km run, it is IS< then the transducer and adaptor ARE working. It its the same as when yo left home, then that gear is suspect.
BUT.
The Yellow wire that goes through that grommet in the tunnel, splits off somewhere near the console front lip, near the whole bunch of wires for the climate system. 1 wire goes to speedo, 1 wire goes the trip computer, 1 wire goes to the cruise control, and they are British, and I have had 2 with that split broken, so maybe.
Not sure what you meant about the driven unit. The transducer only came with like this:
Is this the driven unit you refer to?
It had a yellow looking nylon piece thatprotudes out of it. I understand what you are saying though I think. If the piece that I left alone today has teeth shredded then it won't mesh with the tranducer.
i'll do that trip computer test tomorrow and see if she is changing however I am pretty sure she isn't.
To be continued.
The following 2 users liked this post by paulyling:
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#106
These may help you get a general idea of what can go wrong with the nylon gear that drives the transducer Paul, and how to change it:
And this shows what they look like new
https://www.summitracing.com/int/sea...ion-type/th400
Greg
And this shows what they look like new
https://www.summitracing.com/int/sea...ion-type/th400
Greg
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#107
Found what I was looking for earlier.
#2 is the nylon driven gear.
#1 is the alloy housing, with the o/ring on the outer rim.
#7 is the seal inside that housing.
#8 is the retainer ring for said seal.
39 teeth Jag part @ is C46070, but that may be NLA.
I got mine from a Trans Parts mob near me, but they are long gone.
#2 is the nylon driven gear.
#1 is the alloy housing, with the o/ring on the outer rim.
#7 is the seal inside that housing.
#8 is the retainer ring for said seal.
39 teeth Jag part @ is C46070, but that may be NLA.
I got mine from a Trans Parts mob near me, but they are long gone.
The following 3 users liked this post by Grant Francis:
#108
And a snip at 22pence from JCP !
Part no. C46070 | Speedometer driven gear parts from Jaguar Classic Parts UK
Greg
Part no. C46070 | Speedometer driven gear parts from Jaguar Classic Parts UK
Greg
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#109
Guys thanks a bunch for the info. I am tied up now until the weekend so will get back onto this later in the week.
Got a drive into the city early tomorrow morning for an overnight stay so will have to use the ole' GPS to gauge my speed. I can then look at the Revs and get a rough estimate. That and driving behind other cars on the left lane will work..
Got a drive into the city early tomorrow morning for an overnight stay so will have to use the ole' GPS to gauge my speed. I can then look at the Revs and get a rough estimate. That and driving behind other cars on the left lane will work..
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orangeblossom (01-17-2017)
#110
Ok just came back from my mini road trip (Training course for work with overnight stay).
I can confirm, no change to the trip computer.
Also yes, I only swapped out the speedo transducer itself, I didn't order the rest of the mechanisim that was left:
So I am guessing that swapping out the nylon gear will mean trans fluid out correct?
Also would I swap out the nylon gear on its own (typically) or is it best to order the seal ( part # 7) to swap out when I do the job also? I am assuming part # 1 (housing) will be fine.
If this is the case then it so happens I am due to replace that fluid anyway so might be best to do it at the same time.
Guys thank you again for all your help above
Failing that, look at the trip computer, and note if it is changing ANY numbers after a 10km run, it is IS, then the transducer and adaptor ARE working. It its the same as when you left home, then that gear is suspect
Also yes, I only swapped out the speedo transducer itself, I didn't order the rest of the mechanisim that was left:
So I am guessing that swapping out the nylon gear will mean trans fluid out correct?
Also would I swap out the nylon gear on its own (typically) or is it best to order the seal ( part # 7) to swap out when I do the job also? I am assuming part # 1 (housing) will be fine.
If this is the case then it so happens I am due to replace that fluid anyway so might be best to do it at the same time.
Guys thank you again for all your help above
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orangeblossom (01-21-2017)
#111
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#112
Update:
Just ordered Nylon Driven gear and O-ring # 6 off Doug from Jagdaim.
$5 for the gear which I should get tomorrow.
#7 seal is NLA. Doug says the XJS uses a Jag brand for that seal but the XJ uses a pretty generic seal.
Hopefully I won't need it however I was going to swap it out as a matter of maintenance whilst I was already in there.
To be continued...
Just ordered Nylon Driven gear and O-ring # 6 off Doug from Jagdaim.
$5 for the gear which I should get tomorrow.
#7 seal is NLA. Doug says the XJS uses a Jag brand for that seal but the XJ uses a pretty generic seal.
Hopefully I won't need it however I was going to swap it out as a matter of maintenance whilst I was already in there.
To be continued...
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orangeblossom (01-31-2017)
#113
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#114
Made some progress today whilst underneath changing my trans fluid.
Ok so swapping out the speedo sensor made no change. Time to swap out the nylon gear.
Un bolted the speedo sensor and moved out the way.
Next took off the retaining bracket with a 13mm socket. Why are 80% of bolts on my car 13mm?
And then...I couldn't get the housing out. Watched a You Tube video and they simply just yanked it out....ok doesn't work for me. So I screwed the speed tranducer back in and used some multi grips around the sensor nut to gently lever it out a bit. Then I took off the speedo sensor again and pulled out the housing by hand.
Thar she be, housing and nylon gear.
The nylon gear actually looked ok:
Nevertheless I wanted to swap it out anyway to eliminate this and also installed a new o-ring. Getting it all back in was just a reverse of the above but easier.
Now....that all back in I noticed the wires to my speedo transducer, where I crimped them the other day, were starting to come out! What? I tug tested them when I crimped them and the were ok.
Can't have this...so I soldered and heat shrunk the connection. This is further back and not at the actual plug part. At any rate is should be more reliable.
So....could that have been the problem? I think this may have happened when I was moving the sensor around but I will have to find out tomorrow after I finish servicing my transmission.
Stay tuned....
Ok so swapping out the speedo sensor made no change. Time to swap out the nylon gear.
Un bolted the speedo sensor and moved out the way.
Next took off the retaining bracket with a 13mm socket. Why are 80% of bolts on my car 13mm?
And then...I couldn't get the housing out. Watched a You Tube video and they simply just yanked it out....ok doesn't work for me. So I screwed the speed tranducer back in and used some multi grips around the sensor nut to gently lever it out a bit. Then I took off the speedo sensor again and pulled out the housing by hand.
Thar she be, housing and nylon gear.
The nylon gear actually looked ok:
Nevertheless I wanted to swap it out anyway to eliminate this and also installed a new o-ring. Getting it all back in was just a reverse of the above but easier.
Now....that all back in I noticed the wires to my speedo transducer, where I crimped them the other day, were starting to come out! What? I tug tested them when I crimped them and the were ok.
Can't have this...so I soldered and heat shrunk the connection. This is further back and not at the actual plug part. At any rate is should be more reliable.
So....could that have been the problem? I think this may have happened when I was moving the sensor around but I will have to find out tomorrow after I finish servicing my transmission.
Stay tuned....
Last edited by paulyling; 01-31-2017 at 05:06 AM.
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Greg in France (01-31-2017),
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#115
Paul
if when all back together the speedo still does not go, I am sure there is a meter setting that would test if there is electrical output from the gearbox transducer. The speedo wire come up into the tunnel, but under the console, through a grommet about level with the passenger's thigh/knee area. Worth checking the signal is getting into the cabin, and the joiner plug's integrity once you have repaired the wires.
There are LOADS of dirt cheap speedos in all the breakers in the UK, if it does turn out to be the actual speedo. But could just as easily be the connectors into the binnacle, or the binnacle circuits as well, if the gearbox checks out.
Greg
if when all back together the speedo still does not go, I am sure there is a meter setting that would test if there is electrical output from the gearbox transducer. The speedo wire come up into the tunnel, but under the console, through a grommet about level with the passenger's thigh/knee area. Worth checking the signal is getting into the cabin, and the joiner plug's integrity once you have repaired the wires.
There are LOADS of dirt cheap speedos in all the breakers in the UK, if it does turn out to be the actual speedo. But could just as easily be the connectors into the binnacle, or the binnacle circuits as well, if the gearbox checks out.
Greg
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#116
Thank you Greg,
The moment of truth will be today.
So I am wondering...... if I take out the speedo sensor but still have it connected to the circuit, and I find a point in the circuit with my multimeter on Volts DC and I twist the speedo with my finger what voltage to expect? (if any).
I am wondering also If I would have to have the car running to liven up the Dash perhaps?
Any ideas?
The moment of truth will be today.
So I am wondering...... if I take out the speedo sensor but still have it connected to the circuit, and I find a point in the circuit with my multimeter on Volts DC and I twist the speedo with my finger what voltage to expect? (if any).
I am wondering also If I would have to have the car running to liven up the Dash perhaps?
Any ideas?
#117
If you turn the transducer, you should get about 5 volts AC out of it, if I remember correctly.
The yellow wire is the signal wire to both the speedometer and trip computer, you can always pull out the trip computer and test for continuity between the yellow wire at the trip computer plug and the transducer.
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#118
Ok finished my transmission service today. After all that it was time to test if in fact those poorly crimped wires were the source of my pain the other day....started driving and WELLA! She is working!
Explanation: I think the fault was in fact the speedo transducer. When I wired it up the other day I used cheap charlie insulated lugs. When I was underneath yesterday replacing my nylon gear I noticed that these wires were half hanging out (As mentioned previously) so this time I soldered them and heat shrunk them. This is a splice in the cable I have and not the two pin connector where the transducer connects. I left it so it can still be unplugged if necessary.
Seeing how the nylon gear looked fine I can only assume it was actually the sensor. Never mind the nylon gear is a consumable so it didn't hurt to swap out the $5 part.
My only qualm is.....my speedo will not come alive until after the first gear change. This has been like this ever since I took my dud speedo gauge to a Instrument Repair mob. He confirmed the little PCB was faulty and installed one he gets made up locally. i never complained to him though as at the time I couldn't find a speedo gauge anywhere and this is only a small little annoyance.
All in all...she is fixed....for now.
Thanks for all the help guys. I learnt heaps
Explanation: I think the fault was in fact the speedo transducer. When I wired it up the other day I used cheap charlie insulated lugs. When I was underneath yesterday replacing my nylon gear I noticed that these wires were half hanging out (As mentioned previously) so this time I soldered them and heat shrunk them. This is a splice in the cable I have and not the two pin connector where the transducer connects. I left it so it can still be unplugged if necessary.
Seeing how the nylon gear looked fine I can only assume it was actually the sensor. Never mind the nylon gear is a consumable so it didn't hurt to swap out the $5 part.
My only qualm is.....my speedo will not come alive until after the first gear change. This has been like this ever since I took my dud speedo gauge to a Instrument Repair mob. He confirmed the little PCB was faulty and installed one he gets made up locally. i never complained to him though as at the time I couldn't find a speedo gauge anywhere and this is only a small little annoyance.
All in all...she is fixed....for now.
Thanks for all the help guys. I learnt heaps
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#119
Paul, great news. I meant to mention before, the stick end (as against the lollipop end) of the nylon gear has a square hole in it into which the transducer metal drive fits, quite often this gets rounded so it will not drive the transducer. If you still have the old one, take a look. The lazy speedo is probably a slightly iffy circuit in the instrument binnacle. I think you are VERY sensible to leave it until you feel like a w/e at the dining table with a white tablecloth and R&R-ing the entire instrument pack.
Greg
Greg
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#120
1. You have a bad ground in the instrument panel Or the speedometer is not making good contact at the plug. Tapping the instrument panel is the prime clue! Doug is right on target.
@. illuminating the warning lights works best the farther you get the bulb into the receptacle. I tried T10 LED's and fasten them to the outside of the entry point of the bulb opening. Good, but not a winner. I use T-5's and took them out of the wedge fitting and then soldered the led wire to the Jaguar bulb contacts. The T-5 lighting head slips into the hole and goes in about 3/4 of an inch. With this setup you get light from the original bulb and the LED. Also, there is no modification to the panel and it looks original., except you can now see the warning lights!
@. illuminating the warning lights works best the farther you get the bulb into the receptacle. I tried T10 LED's and fasten them to the outside of the entry point of the bulb opening. Good, but not a winner. I use T-5's and took them out of the wedge fitting and then soldered the led wire to the Jaguar bulb contacts. The T-5 lighting head slips into the hole and goes in about 3/4 of an inch. With this setup you get light from the original bulb and the LED. Also, there is no modification to the panel and it looks original., except you can now see the warning lights!
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paulyling (02-07-2017)