A sticky/worn speedo cable will cause the speedo to twitch.
You can fit a ratio box or drive joint to solve the ratio problems. Flexible Drive Agencies list the ratio boxes as drive joints. Flexible Drive Agencies make both standard speedo cables and a cable to suit the ratio box.
VDO electronic speedo
Started by
_Herne_
, Nov 17 2010 01:32 PM
47 replies to this topic
#26
ls2lxhatch
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Posted 18 November 2010 - 08:43 PM
#27
_Herne_
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Posted 18 November 2010 - 10:30 PM
A sticky/worn speedo cable will cause the speedo to twitch.
You can fit a ratio box or drive joint to solve the ratio problems. Flexible Drive Agencies list the ratio boxes as drive joints. Flexible Drive Agencies make both standard speedo cables and a cable to suit the ratio box.
Umm the drivejoint link reads:
Method of Calculating Drive Joint Ratio
1. Remove old drive joint, if fitted, connecting the flexible shaft directly to the transmission.
2. Drive vehicle on a measured course of ~ 5 km. The longer the course, the more accurate the test.
3. Note distance measured on the odometer.
4. The Drive Joint Ratio can then be calculated as follows:
Actual Distance Travelled / Odometer Reading = Drive Joint Ratio
How can I do this when the speedo is not working or reading totally inaccurate?
Have I grasped this concept correctly?
Cheers
Herne
#28
ls2lxhatch
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Posted 18 November 2010 - 11:17 PM
You need a speedo that is working but over or under reading. A twitching needle should not affect the odometer reading.
Method of Calculating Drive Joint Ratio
1. Drive vehicle on a measured course of ~ 5 km. The longer the course, the more accurate the test.
2. Note distance measured on the odometer.
3. The Drive Joint Ratio can then be calculated as follows:
Actual Distance Travelled / Odometer Reading = Drive Joint Ratio
If it turns out that you drove for 5 km and the odometer read 5.5 km then you would fit a 5/5.5 (0.9090) ratio drive joint.
Method of Calculating Drive Joint Ratio
1. Drive vehicle on a measured course of ~ 5 km. The longer the course, the more accurate the test.
2. Note distance measured on the odometer.
3. The Drive Joint Ratio can then be calculated as follows:
Actual Distance Travelled / Odometer Reading = Drive Joint Ratio
If it turns out that you drove for 5 km and the odometer read 5.5 km then you would fit a 5/5.5 (0.9090) ratio drive joint.
#29
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Posted 19 November 2010 - 11:37 AM
Ahh gotcha now 
^^^^^ I have to decide which way to go, I reckon I will have made a decision before this time next week.
Cheers
Herne
^^^^^ I have to decide which way to go, I reckon I will have made a decision before this time next week.Cheers
Herne
#30
_CHOPPER_
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Posted 19 November 2010 - 04:28 PM
New speedo cables can be made to order down here in Melb. Or I could look in the garage for a spare cable...
#31
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Posted 19 November 2010 - 05:43 PM
Before I look, I must state that I would only have a Trimatic speedo cable in the garage. Don't you run something else?
#32
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Posted 19 November 2010 - 06:57 PM
Hi, Chopper
I run a Trimatic albeit a bit modified but that in no way changes the speedo drive.
Mate please let me know what you have as i am yet undecided which way to go.
I thought i was doing ok financial wise but then this evening we opened the mail to find a massive (for us) electricity bill. Seems being ill over winter has its costs lol
Cheers
Herne
I run a Trimatic
albeit a bit modified but that in no way changes the speedo drive.Mate please let me know what you have as i am yet undecided which way to go.
I thought i was doing ok financial wise but then this evening we opened the mail to find a massive (for us) electricity bill. Seems being ill over winter has its costs lol
Cheers
Herne
#33
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Posted 20 November 2010 - 08:39 PM
I just paid my $500 electricity bill, so I know the problem.
#34
_Squarepants_
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Posted 21 November 2010 - 10:02 AM
I had a new circuit board put into my original tacho by Otto's Instruments in Brisbane.
I can't remember exactly how much it cost but it was a damn sight cheaper than buying a new gauge.
I think most instrument shops could make a new speedo cable and supply a ratio box to suit your needs... You just need to work out what ratio you need.
I can't remember exactly how much it cost but it was a damn sight cheaper than buying a new gauge.
I think most instrument shops could make a new speedo cable and supply a ratio box to suit your needs... You just need to work out what ratio you need.
#35
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Posted 21 November 2010 - 10:46 AM
Hi squarepants, I was thinking of checking the ballpark price to have the original tacho repaired esp after getting the shocking electricity bill (pun intended) lol
Still deciding whether to go with the 260 kph GPS speedo though, it's mighty tempting but then chopper has got me thinking along the lines of a new cable and gismo.
Xmas is around the corner, wonder if I can get the speedo as a pressy
Cheers
Herne
Still deciding whether to go with the 260 kph GPS speedo though, it's mighty tempting but then chopper has got me thinking along the lines of a new cable and gismo.
Xmas is around the corner, wonder if I can get the speedo as a pressy
Cheers
Herne
#37
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Posted 21 November 2010 - 11:34 PM
I've just shot a PM to you Allan.
Thanks John, read it and replied mate.
Cheers
Alan
#38
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Posted 22 November 2010 - 06:01 AM
A flickering speedo needle can also be caused by worn speedo drive and driven gears, a problem Ive had on 5 out of 5 toranas/sunbirds. Often the problem gets worse or better(cant remember) as the gearbox warms up. The drive gear on your trimatic may well be very worn causing the problem. Its possible to feel it if your fingers are long enough, or use a mirror and torch to actually view it. Refitting another one(you believe you need another ratio anyway) 'simply' involves removing the extension housing and not the whole box.
#39
View GaragePosted 22 November 2010 - 06:41 AM
Just remember that anything GPS is going to be very slow to react. Its handy to have an accurate number when travelling in a straight line at a consistent speed, but not sure if I'd want one for the main speedo.Still deciding whether to go with the 260 kph GPS speedo though
#40
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Posted 22 November 2010 - 08:15 AM
A flickering speedo needle can also be caused by worn speedo drive and driven gears, a problem Ive had on 5 out of 5 toranas/sunbirds. Often the problem gets worse or better(cant remember) as the gearbox warms up. The drive gear on your trimatic may well be very worn causing the problem. Its possible to feel it if your fingers are long enough, or use a mirror and torch to actually view it. Refitting another one(you believe you need another ratio anyway) 'simply' involves removing the extension housing and not the whole box.
I wasnt sure what was required to replace the inner drive gear, thanks for that bit of info its very handy, we have the engine out right now but not the auto so it would be a good time to look at it, with a bit of luck Chopper is finding me an unmolested speedo cable thats not badly worn. If all this works it will save me a good few hundred dollars.
76LXhatch. I hadnt thought about a time lag on the gps, now you really have me thinking which is not a bad thing lol.
Cheers
Al.
Edited by Herne, 22 November 2010 - 08:16 AM.
#41
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Posted 22 November 2010 - 11:39 AM
Of course removing the extension housing means to get the car up in the air and on jack stands and supporting the Trimatic under the pan whilst removing the tailshaft, cross member and extension housing. It may pay to get the bush in the back of the extension housing replaced while it's off. Most auto trans places here in Melbourne offer a changeover service. You give them the old one and some cash and they give you a clean one with a new bush and seal fitted and of course a new gasket. Trade price back in 2003 was $27.50.
Most new GPS units update every second and the update rate can be altered in the main menu. In theory, a GPS speedo will only be 100% accurate on a straight, level road at a constant speed. Please realise that fixed and hand held police radars are also only 100% accurate on a straight, level road. GPS units do NOT work in long tunnels such as the East link tunnels here in Melbourne. Personally, I would use an electronic or mechanical speedo as the main unit and have a GPS unit to periodically check it when on straight, level roads when traveling at a constant speed.
Most new GPS units update every second and the update rate can be altered in the main menu. In theory, a GPS speedo will only be 100% accurate on a straight, level road at a constant speed. Please realise that fixed and hand held police radars are also only 100% accurate on a straight, level road. GPS units do NOT work in long tunnels such as the East link tunnels here in Melbourne. Personally, I would use an electronic or mechanical speedo as the main unit and have a GPS unit to periodically check it when on straight, level roads when traveling at a constant speed.
#42
_Herne_
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Posted 01 December 2010 - 05:15 AM
Hi Guys, many thanks to all those that took the time to read my message and reply to it. Your advice and offers of help was appreciated.
The upshot is I checked the speed hut website earlier this morning to find that they have a 15% discount currently running on speedo's etc. Plus they are offering $10.00 discount on shipping so the shipping came in at $24.00 which made me well pleased.
I placed an order for the 4" 260kph GPS unit, and yes i will wear the 1 second delay and lack of speedo whilst in a tunnel but luckily Canberra has very few tunnels and they are incredibly short compared to what Melb. and Syd. has.
I also managed to get a good few dollars help in the way of Xmas presents to assist with the purchase.
I will either get my tacho looked at by Premier Instruments OR I may wait a while and order the matching tacho from these guys (speed hut).
Cheers
Herne
The upshot is I checked the speed hut website earlier this morning to find that they have a 15% discount currently running on speedo's etc. Plus they are offering $10.00 discount on shipping so the shipping came in at $24.00 which made me well pleased.
I placed an order for the 4" 260kph GPS unit, and yes i will wear the 1 second delay and lack of speedo whilst in a tunnel but luckily Canberra has very few tunnels and they are incredibly short compared to what Melb. and Syd. has.
I also managed to get a good few dollars help in the way of Xmas presents to assist with the purchase.
I will either get my tacho looked at by Premier Instruments OR I may wait a while and order the matching tacho from these guys (speed hut).
Cheers
Herne
Edited by Herne, 01 December 2010 - 05:25 AM.
#43
GML-31
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Posted 01 December 2010 - 05:56 AM
Herne a brand new speedo cable is only $76 on rares website?
#44
_Herne_
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Posted 01 December 2010 - 06:08 AM
Yes but I required more than a speedo cableHerne a brand new speedo cable is only $76 on rares website?
My speedo itself may have a problem, unsure yet. PLUS we had a problem with the speedo gear not knowing what colour or tooth the drive gear is. IF the speedo had a problem the cost was going to mount up anyway, this way I have no concerns with drive gears or anything else. Nothing more to buy.Besides that its Xmas
and the Dream could do with a bit of a tart up lolCheers
Herne
#45
_2wild4u_
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Posted 16 January 2011 - 04:50 PM
to everyone that has the vdo electric speedo, when you calibrated it did you drive one km or 1 mile? as i have two different instructions here and they both say different, im sure its pretty acurate but sometimes the speedo seems to fluctuate
#46
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Posted 20 January 2011 - 07:34 AM
Mine was 1km.
Cheers
Mark
Cheers
Mark
#47
ls2lxhatch
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Posted 20 January 2011 - 10:43 AM
I have not calibrated mine yet.
However it would make sense that the instructions for the mph speedo tell you to drive one mile and the instructions for the km/h speedo tell you to drive for one km. There should also be a calibration mode where you can tell the speedo the number of pulses per km. Typically you would initially calibrate by driving for a km and the speedo will record the number of pulses per km. Then you would fine tune the speedo by manually adjusting the pulse count.
The speedo basically just counts pulses from the gearbox per second (sample time may be different) and then calculates speed using the calibrated number of pulses per km. The odometer reading is the number of pulses counted divided by the calibrated pulses per km.
If you have calibrated the wrong number of pulses per km then the speedo should be consistently over or under reading. If the speedo fluctuates then I would be looking for a fault in the wiring, speedo or sensor.
However it would make sense that the instructions for the mph speedo tell you to drive one mile and the instructions for the km/h speedo tell you to drive for one km. There should also be a calibration mode where you can tell the speedo the number of pulses per km. Typically you would initially calibrate by driving for a km and the speedo will record the number of pulses per km. Then you would fine tune the speedo by manually adjusting the pulse count.
The speedo basically just counts pulses from the gearbox per second (sample time may be different) and then calculates speed using the calibrated number of pulses per km. The odometer reading is the number of pulses counted divided by the calibrated pulses per km.
If you have calibrated the wrong number of pulses per km then the speedo should be consistently over or under reading. If the speedo fluctuates then I would be looking for a fault in the wiring, speedo or sensor.
#48
_2wild4u_
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Posted 21 January 2011 - 12:09 AM
yeah i might try doing it again, the sender has been replaced to make sure it wasnt at fault, wiring is all good, maybe speedo might be at fault i will try again and see how i go, thanks
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