Hi Robert
That is what I did with old mounted speedo. The wire colors were yellow and green from the system and the speedo was brown and yellow with black stripe. Yellow should be signal and the brown was 12 v. I tried yellow to yellow/blk and it did not work as I thought it would. Green of the system went to yel/blk and brown went to yellow. So I will swap and see what happens.
Keep in mind that none of this speed interface existed in my trunk. My speedo was in the TH400 so I am also trying to find out if the red and blue wires should be coax
I have a 96 DAC-11399 whats up with the coax???
thanks Chris
That is the later interface that should be correct for the late differential; donât think you can swap to the earlier due to connector differences. Donât know if the pulse rate is different.
Abbott and previous mentioned Dakota Digital make pulse rate tuning modules; there are also GPS pulse generators from VDO and others ($150)
Sounds like your pulse rate is too low by 1/3âŚhopefully switching the interface outputs will help.
Coax is to eliminate interference, probably not causing issue but you could try a shield wire.
Hey Robert
So you are saying that the DAC-11399 will be us-less in this instance.
If that is the case how would a tuning module integrate into the system?
Is there a schematic for the 11399?
Thanks
Chris
I am thinking that you would use your interface module with a correction device. Is your speed reading steady and proportional to actual speed? If so, then the correction device would multiply frequency.
GPS would do away with vehicle sensor and interface.
https://forums.jag-lovers.com/uploads/short-url/JueLDeOT9rviM77Q94ImIQwzB3.pdf
Above is for â88/89 with differential sensor; I think facelift is similar.
The speed is steady and it takes a few seconds for the speedo to register.
but it seems proportional to speed but the speed is way low on the speedo.
I am thinking that a correction device would do the trick.
With the original speedo I set up a test to bypass the trans and spun the paddle and the needle reacted immediately. I will check my connections and do more tests. What would method would you pick and why.
Thanks
Chris
GPS is probably the easiest to set up and isnât affected by tire size or final drive ratio- you press calibrate, drive a while, press calibrate and you are done. May not support any mileage functions on the travel computer.
Correction module requires you to drive 10 miles, compare to what your odometer says, and set a bunch of dip switches to correct reading; their tech line may be able to give you a starting setting. If you connect it before your interface, may support the traveler.
Might be worth a phone call to both vendors for their suggestion.
Another solution may be a speedo from a late â88 to â91 that might read correctly from the interface you have. This is probably the way I would go, because I am cheap and like to beat my head against the wallâŚ
I am the same way until there is not enough head to bang on. I think I over thought what was going on here. The fact that my 88 schematic shows the speed interface later in 88 means it should work. I donât know if the 5 speed plays a role but I donât think so.
Ratios: 2.87, 1.89, 1.28, 1.00, .82
with the 3.54 diff.
The main change was to incorporate the diff sensor and they must have had to make a change to the the speedometer.
The Speed interface is fundamentally the same.
The other thought would be to find the output resistor that can be tweaked a bit. I do like that the speedometer would organic.
West Valley Instruments may be able to help modify the existing speedo to work with the interface; call or email them.
I know that I was able to modify my OE 4cylinder tach on my MGB when I put the V8 in it, been a while, but was just a resistor change and seems accurate.
Here is another possibility what if there was a change for 94 3.54 diff
I came across this on Jagbits and this is what they have for the speedo.
SPEEDOMETER SENDING UNIT (TRANSDUCER), FITS 1988-1993 V12 XJS FROM VIN 144262 up to VIN 188104.
This is when the switch was made to go to the diff for the sender.
That made me wonder if it stopped at 188104 for some reason and changed pulse rate. the 94 diff.
I will check out West Valley and others. It may be a longshot for the for the change but may be the solution.
The pulse rate would be governed by the number of notches on the diff case (which turns at wheel speed); if I recall my â88 (1463xx) has maybe 10, which approximates the 8000/mile. Maybe later had fewerâŚmaybe count how many you have and look up tire revs per mile for recommended tire size.
Does maybe the 188xxx VIN have Teves IV and get a road speed signal from the ABS? My understanding is that Teves III cars still had the differential sensor.
YUP. A unit from Dakota DigitalâŚ
Jaguar - specialties has a simpler un tâŚ
I have one of each!!!
Carl
Hey Robert
Got busy but am on the track again. There should be difference between the 2.88 to the 3.54 diff pulses.
My trip computer, speedo and odometer are working but there is an error.
If I drive 8 miles I register about 7. It may be because the different diffs. I have a pulse generator coming from Ebay for $5 that may that will let me select the frequency and drive the speedo.
Signal Generator Module Adjustable PWM Pulse Frequency Duty Cycle Square Wave L
I will let you know if it works
Cheers
Chris
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Sounds like you are getting close, good job.