speedo issues after 1uz conversion.

[Shane]

As I have never come across this issue, I have never looked into it.

 

Stripping the no.1 sensor will be an easy enough one 10mm bolt job, but I can't get at it because there's another box in the way.

 

Before I was a Spaz, I used to pick these things up with one hand.

 

I spoke to Paul and we will come over in the next week or so, he prefers the weekend. His car is going back to the paint shop next week as theres a couple of small issues he's not happy with and the guy has agreed to rectify so will try and get over before then so you can see his car.

[David P]

There will be beers in the fridge and/or the kettle on stand-by.

 

Looking forwards to seeing the Supra in one colour.

[Delboy52]

Shane, I've got a box with spare speed sensors from both Supra NA and TT autos, and the Lexus A650 if you need parts to test with. The black two pin analogue magnetic sensors and the three pin digital geared one. On my A343e TT box it's the No1 three pin sensor that goes to the combination meter dash display. It's always worked so I've never had to pay it much attention.

 

Let me know if you need bits.

[Mike2JZ]

I guess the question is. Is the sensor outputting too many pulses due to the shaft it's reading from, or is it because of the sensor? I had a quick look over the parts diagram from Supra/LS400, but couldn't decifer this.

 

Failing all of the above, short of changing the box I guess you could try one of these: http://www.dakotadigital.com/index.cfm/page/ptype=product/product_id=126/category_id=-1/mode=prod/prd126.htm

[RastaMc]

I guess the question is. Is the sensor outputting too many pulses due to the shaft it's reading from, or is it because of the sensor? I had a quick look over the parts diagram from Supra/LS400, but couldn't decifer this.

 

Failing all of the above, short of changing the box I guess you could try one of these: http://www.dakotadigital.com/index.cfm/page/ptype=product/product_id=126/category_id=-1/mode=prod/prd126.htm

 

Yeah, that is a good instrument to use. I am using it after the conversion of me gearbox. And it works very well. I connected it to the abs signal.

[Shane]

Shane, I've got a box with spare speed sensors from both Supra NA and TT autos, and the Lexus A650 if you need parts to test with. The black two pin analogue magnetic sensors and the three pin digital geared one. On my A343e TT box it's the No1 three pin sensor that goes to the combination meter dash display. It's always worked so I've never had to pay it much attention.

 

Let me know if you need bits.

 

Hi Mike, thanks. Yes sensor No.1 which drives the speedo is the 3 pin one and thanks for confirming its this that you used to drive your speedo. May take you up on the kind offer depending on how we get on with Dave's.

 

I guess the question is. Is the sensor outputting too many pulses due to the shaft it's reading from, or is it because of the sensor? I had a quick look over the parts diagram from Supra/LS400, but couldn't decifer this.

 

Failing all of the above, short of changing the box I guess you could try one of these: http://www.dakotadigital.com/index.cfm/page/ptype=product/product_id=126/category_id=-1/mode=prod/prd126.htm

 

Exactly this, thanks for your input. I am concerned that the gearing to the No.1 sensor on this box merely turns the shaft five times faster than it does on the later boxes. Looking through the other forums I cant be 100% sure if simply changing the sender will fix it. What I intend to do initially is put a scope on the one Dave has offered and then pull the one from our box and do the same test, think its the only way I can be sure.

 

Yes I saw the Dakota unit in post from Lextreme which I posted earlier. Looks like a versatile unit and given how much time its going it will take to write a bit of code and make something up its probably worth the punt.

Edited November 13, 2018 by Shane (see edit history)

[David P]

After raking through Toyodiy, it would appear that the speed sensors are the same items on A340E and A341E transmissions, so by default the difference must be on the shaft inside the box.

[TRD-1]

I think the way the speedo signal works is different depending on the engine/box and ecu that is used. If using the pre 1995 engine/box and ecu which come from the UCF10 LS400 and Soarer (not sure on years) then the speedo signal is driven via the No.1 speed sensor, in which case changing the speedometer driven gear might work to get the speedo to be accurate.

 

But on the post 95 engines which came in the UCF20 LS400 the speedo signal is sent from the ECU via the SPDM pin, and both of the speed sensors are connected directly to the ECU.

 

The speedometer driven gears are different for each model, so I guess the speedo you have in the Supra weather its a GTE one or a GE one is the gear you will need.

 

Well done for working all this out for future conversions!

Edited November 13, 2018 by TRD-1 (see edit history)

[David P]

I have had a look in my A340E repair manual and have discovered that I have been mixed up between the no. 1 & 2 speed sensors, I can only think this misconception originated from previously referring the useless diagrams in Toyodiy?

 

Excuse me.

 

Now that I have my sensors on straight, swapping in the gear-pair from this GS300 box I have will solve the problem.

 

 

 

 

Edited November 13, 2018 by David P (see edit history)

[David P]

I have done some more trawling through Toyodiy and have found that the no.1 speed-sensor gear-pair in 94 LS400 and 95 T.T. Supra are the exact same items?

 

http://www.toyodiy.com/parts/p_E_1994_LEXUS_LS400_UCF10L-AEPGKV_3510.html

 

http://www.toyodiy.com/parts/p_E_1994_LEXUS_LS400_UCF10L-AEPGKV_3505.html

 

http://www.toyodiy.com/parts/p_E_1995_TOYOTA_SUPRA_JZA80R-ALPVZW_3510.html

 

http://www.toyodiy.com/parts/p_E_1995_TOYOTA_SUPRA_JZA80R-ALPVZW_3505.html

[Shane]

I have done some more trawling through Toyodiy and have found that the no.1 speed-sensor gear-pair in 94 LS400 and 95 T.T. Supra are the exact same items?

 

http://www.toyodiy.com/parts/p_E_1994_LEXUS_LS400_UCF10L-AEPGKV_3510.html

 

http://www.toyodiy.com/parts/p_E_1994_LEXUS_LS400_UCF10L-AEPGKV_3505.html

 

http://www.toyodiy.com/parts/p_E_1995_TOYOTA_SUPRA_JZA80R-ALPVZW_3510.html

 

http://www.toyodiy.com/parts/p_E_1995_TOYOTA_SUPRA_JZA80R-ALPVZW_3505.html

 

What about a 89 LS400 UCF10?

[David P]

There isn't an 89, but the 90 is same.

 

http://www.toyodiy.com/parts/p_E_1990_LEXUS_LS400_UCF10R-AEPGKW_3505.html

 

http://www.toyodiy.com/parts/p_E_1990_LEXUS_LS400_UCF10R-AEPGKW_3510.html

[Shane]

There isn't an 89, but the 90 is same.

 

http://www.toyodiy.com/parts/p_E_1990_LEXUS_LS400_UCF10R-AEPGKW_3505.html

 

http://www.toyodiy.com/parts/p_E_1990_LEXUS_LS400_UCF10R-AEPGKW_3510.html

 

I found this:

 

 

Early Vss - 83181-50010 Listed for USDM until 08/92 but listed for some other markets for the whole range of UCF10. Seems pretty much lexus only

 

Later Vss - 83181-24040 Listed for a wider range and also seems to be used in some models back until 1989.

 

 

 

Also, realised that he has a ECU Master DET3 piggy back to go in so in time we can lose the MAF. This has the capability of frequency conversion too Page32 - 35 http://www.ecumaster.com/wp/wp-content/uploads/2016/11/Digital-ECU-Tuner-III-Manual-English.pdf

Edited November 13, 2018 by Shane (see edit history)

[David P]

I believe that part number is just for the sensor and not the gears?

[Shane]

I believe that part number is just for the sensor and not the gears?

 

Yes.

[David P]

Because I've never found or heard of any speedometer compatibility issues resulting from swapping transmissions of different dates into Supra's.

 

I can't see it having a different pulse signal, just a superseded component?

 

http://www.toyodiy.com/parts/xref?s=83181-24040&mE=on

 

For instance(s), Delboy52's Supra is a 93 N/A with a later A343E U.K. T.T. box and bluesonic94's is a 93 N/A-T with a later A340E J-spec box.

Edited November 13, 2018 by David P (see edit history)

[David P]

You could i.d. the exact age of your A341E transmission from the Aisin Warner plate, see bottom of page linked.

 

http://www.mkivsupra.net/vbb/group.php?discussionid=153&pp=10&page=2&do=discuss

 

Then you could i.d. the sensor you have?

[Shane]

Because I've never found or heard of any speedometer compatibility issues resulting from swapping transmissions of different dates into Supra's.

 

I can't see it having a different pulse signal, just a superseded component?

 

http://www.toyodiy.com/parts/xref?s=83181-24040&mE=on

 

For instance(s), Delboy52's Supra is a 93 N/A with a later A343E U.K. T.T. box and bluesonic94's is a 93 N/A-T with a later A340E J-spec box.

 

 

So what are you saying, you don't think there are five times more pulses coming from sensor No.1 on ours and you still think its something else like the way its connected? Dellboy has confirmed the way his is connected and its the same as ours. 2JZMike also confirmed the wiring method as does the link below, as in the frequency generated leaves the collector of the transistor in the vss and feeds the speedo, what happens after this is irrelevant in terms of the odo buffer and ecu. A test with a second speedo wired direct to the VSS produces the same.

 

Its not that complex and very old school electronics, I don't know the thinking back then of why they used a different pulse rate and speedo on the early 400 but it seems they did. Did you get chance to read all of this:

http://www.lextreme.com/forums/index.php?threads/w58-in-ls400-what-a-p-i-t-a.15612/

http://www.lextreme.com/forums/index.php?threads/1uz-speedo-setup-with-rf1a-t-case-help.16249/

 

Most people use Soarers as their base and and the VSS is the same as the Supra so there are no compatibility issues. I will get the id from the box if its still readable, but we know it came from a 89 plated LS400. Do you know anyone who has used an early LS400 with the box and ecu to ask, or even a box from one? I don't.

 

If I get chance at the weekend I will scope the output from Paul's and also from mine and see what the difference is, I believe it will provide conclusive data. It's possible that the gearing ratio is different, or it could be the sensor is constructed differently to provide the higher frequency that we are seeing. But, now I have thought about using the det3 ecu he already has, I think if it's a speedo drive gear ratio difference it will be easier wire that in than trying to change the gears with the box in situ.

[David P]

If I get chance at the weekend I will scope the output from Paul's and also from mine and see what the difference is, I believe it will provide conclusive data.

 

This would give the definitive answer.

[TRD-1]

So firstly from digging deeper into Toyo I found that the LS400 UCF10 Speedometer sensor part no. 83181-50010 is Not for Euro spec, this part number is only used in the J spec Toyota Celsior (LS400) of the same year and for cars that went to Australia, General countries (whatever they are according to toyo), and Gulf corporation council, so it wouldn't apply to UK cars, if you search this number on Toyo and then click on the EUR spec car it reverts you back to part number: 83181-24040

 

And from here just to pair some things up on this, so we know what cars have got what:

 

UCF10 UK/Eur Spec 1990 - 1994 Speedometer sensor no: 83181-24040 Speedo Driven Gear: 33482-59015 (N=17, Mark 17:6)

 

GS300 UK/Eur Spec 1993 - 1997 Speedometer sensor no: 83181-24040 Speedo Driven Gear: 33482-29205 (N=19, Mark 19:6)

 

Soarer J spec 1991> Speedometer sensor no: 83181-24040 Speedo Driven Gear: 33482-59025 (N=18, Mark 18:6)

 

Supra TT J spec 1993> Speedometer sensor no: 83181-24040 Speedo Driven Gear: 33482-59025 (N=18, Mark 18:6)

 

Supra TT UK/EUR Spec 1993> Speedometer sensor no: 83181-24040 Speedo Driven Gear: 33482-59015 (N=17, Mark 17:6)

 

Supra NA J Spec 1993> Speedometer sensor no: 83181-24050 Speedo Driven Gear: 33482-39415 (N=20, Mark 20:6)

 

So from here we could say that using the box from a UCF10 any year and leaving the sensor alone changing the speedo driven gear to one from a Supra J spec TT or Soarer and using a speedo kmh to mph converter would give you the correct and accurate signal in mph according to paper!....However if there is any difference that is created by the speedo assembly unit itself that im not sure of yet, but it doesn't seem so.

 

Or two alternatives would be using the UCF10 box and speedo driven gears and fit a UK spec TT Speedo assembly, or secondly leave the UCF10 gearbox and speedo driven gears and fit a speedo signal converter like the km/h to mph converters but I don't know if you might need to also change the speedo face to get it accurate, as all JDM speedo units run in km/h giving them a direct mph signal might result in what your experiencing.

Edited November 14, 2018 by TRD-1 (see edit history)

[David P]

You have just exposed that the Toyodiy, "New - Search by Part Number" function (that I used), doesn't work properly?

 

The different gear-pairs that you have correctly identified, thank you, correspond to the different differential-ratio's and different OE wheel size & tyre profile combinations in the different cars listed. This gear-pair difference mechanically adjusts the resulting electronic speed-signal to a "common-pulse" for the ECU's and speedometers.

 

For instance, the resulting speedo-error after swapping an N/A A340E-GE box that had 4.083 diff speed-sensor gears, for a Hybridised T.T. A340E-GTE box that has 3.769 diff speed-sensor gears when still running with an N/A 4.083 differential; is around 4.5%? raised on speedometer and with an influence on moment of gear-changes, becoming lowered by around 300? engine rpm. (plus or minus influence from whatever sized wheels and tyre profile differing from OE?)

 

I don't know what differential Paul's Supra is running and can't remember the wheel/trye - size/profile combo?, but if it has a T.T. auto A02A or B, that I would suspect, the resulting final-drive ratio compatibility shouldn't be far off?

 

I haven't wasted my time with/by chasing after all of the different before and after wheel measurements and tyre-sizes & profiles and differential final-drive ratio's and then bent my mind with complicated mathematics, because, my ready-reckoning reckons that these differences are not different enough to cause the apparent far larger discrepancy?

Edited November 16, 2018 by David P (see edit history)

[Shane]

OK so I pumped the tyres up and dug the TT out of the garage to make the comparison between sensor outputs.

 

Output from No.1 sensor on the original TT 1995 box is approx 32Hz @ 20mph

 

Output from the No.1 sensor on the 1989-90ish LS400 box is approx 130Hz @ 20mph

 

I have now fed the No.1 sensor into the DET3 ECU and used the frequency conversion feature and running the speedo from it. Stuck in a multiplication factor of 0.25 just to see if it worked and the speedo is now tamed, not accurate but not off the end stop at 30mph like previously. It was getting cold and dark so tomorrow I will tweak this and get it calibrated against gps.

 

Have a few pictures so will get them up here when I have scaled them down, such a pain now photobucket has gone to get pictures up here.

[David P]

Have you identified what is multiplying the signal X 4?

 

I believe that the ECU multiplies the transmissions 4 blips per rev to 16, are both of those readings pre-ECU?

Edited November 17, 2018 by David P (see edit history)

[Shane]

Have you identified what is multiplying the signal X 4?

 

I believe that the ECU multiplies the transmissions 4 blips per rev to 16, are both of those readings pre-ECU?

 

That was pre ecu straight from the collector of the VSS. No.1 sensor output doesn't get to the ecu until its been to the speedo and through the odo. Why would the ecu multiply anyhow, what would be the point?

 

Either, the gears in the box are turning the vss 4-5 x faster or (less likely) the vss shaft has 4 or 5 magnetic splines rather than one, as the box is in the car I don't intend to find out. But according to the part numbers you put up the sensors are the same so this would suggest gearing.

[David P]

SupraStick is set at 16 blips per rev from speed-sensor, so if the X4 is not done electronically, it must from the gear-pair?

 

It is why your's has 4 x times more again that's the mystery?