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Technical => Electrical Tech => Topic started by: 20thanvcat on May 04, 2017, 06:25:08 PM

Title: electronic instrumentation recalibration
Post by: 20thanvcat on May 04, 2017, 06:25:08 PM
has anyone recalibrated an electronic cluster,evtm says "recalibrate" as per shop manual  fuel gauge seems low, not real sure on the other gauges:D
Title: electronic instrumentation recalibration
Post by: jcassity on May 17, 2017, 09:32:41 PM
interesting,,
what page you on?
Title: electronic instrumentation recalibration
Post by: 20thanvcat on May 22, 2017, 07:57:08 AM
apology's  it was fuel gauge I was reading. I have the full electronic (digital dash ) as im sure you do in the 20th anv , my issue is the spedo is inaccurate 10 mph + , would you happen to have the part # for the correct one ? i have the correct driven/ drive gears( yellow on trans (t5) and 21 tooth (red) on sensor)
Title: electronic instrumentation recalibration
Post by: jcassity on May 22, 2017, 11:38:37 AM
this is something i am not the best person to speak to about.
I've changed speed sensors before,,easy job but,,,,

i think i know a source.

my 351 bronco i converted to 5speed and the gear color  is yellow.

the source for the transmission i used was your 89, 90, 91 F100 or F150 etc with the 5 speed Mazda TK transmisison.
Title: electronic instrumentation recalibration
Post by: TurboCoupe50 on May 22, 2017, 01:03:51 PM
Quote from: 20thanvcat;460863
apology's  it was fuel gauge I was reading. I have the full electronic (digital dash ) as im sure you do in the 20th anv , my issue is the spedo is inaccurate 10 mph + , would you happen to have the part # for the correct one ? i have the correct driven/ drive gears( yellow on trans (t5) and 21 tooth (red) on sensor)

Well if it's reading too fast you need a drive gear in transmission with less tooth count... Dropping from 8T(guessing that what's inside) to 7T will make a large difference...  The 21T driven gear is as many teeth as Ford sells but there is a aftermarket 23T available... That one should slow down reading approx 5-7 mph... Clinker is they are reported to have a short life...
Title: electronic instrumentation recalibration
Post by: tommym on May 22, 2017, 09:50:27 PM
If you have a good Ford parts guy they have a formula to figure out the drive gear. You'll need the part number of your trans and your rear gear ratio.
Title: electronic instrumentation recalibration
Post by: TurboCoupe50 on May 22, 2017, 10:19:33 PM
Quote from: tommym;460885
If you have a good Ford parts guy they have a formula to figure out the drive gear. You'll need the part number of your trans and your rear gear ratio.

No parts guy necessary, there are online calculators...


Here's one from Ford Racing Parts... If calibration is wrong with listed gears there are other factors in play, like tire size or maybe a flaky speedo head...

https://performanceparts.ford.com/download/pdfs/SpeedometerGearUsageChart.pdf
Title: electronic instrumentation recalibration
Post by: 20thanvcat on May 23, 2017, 12:27:20 PM
ford racing has the formula - and according to the spec, i have the correct setup for my combo --thats why i was wondering about the sensor self , seems it would have to be diffrent for a buttstuffog dash vrs the full digital dash ?
Title: electronic instrumentation recalibration
Post by: TurboCoupe50 on May 23, 2017, 12:36:44 PM
Quote from: 20thanvcat;460892
ford racing has the formula - and according to the spec, i have the correct setup for my combo --thats why i was wondering about the sensor self , seems it would have to be diffrent for a buttstuffog dash vrs the full digital dash ?
Nope a gear for a T-Bird with buttstuffog or digital dash is same, or Mustang, Crown Vic etc... Would be a major kludge if heads were calibrated differently...

All speedos are calibrated(or at least were, now days it's a whole different game) to read 60 mph at sensor or cable speed of 1000 rpm..


What is your combination and exact issue(include gear ratio)... Hard to help if all the details are not known...
Title: electronic instrumentation recalibration
Post by: 20thanvcat on May 23, 2017, 03:50:43 PM
ok :
 t5 trans has yellow gear (7 tooth on output shaft)
speed sensor has red gear( 21 tooth on speed sensor)
rear axle is 3.73 gear

according to ford racing speedometer gear useage chart for 7.5-8.8 axle this is the correct setup
this is a used electronic cluster reading aprox 10 mph high i:e;reading 85 (and this is max for this cluster will not go to 87-88-89mph )at 75mph
Title: electronic instrumentation recalibration
Post by: TurboCoupe50 on May 23, 2017, 07:13:57 PM
Quote from: 20thanvcat;460897
ok :
 t5 trans has yellow gear (7 tooth on output shaft)
speed sensor has red gear( 21 tooth on speed sensor)
rear axle is 3.73 gear

according to ford racing speedometer gear useage chart for 7.5-8.8 axle this is the correct setup
this is a used electronic cluster reading aprox 10 mph high i:e;reading 85 (and this is max for this cluster will not go to 87-88-89mph )at 75mph


You sure this thing doesn't have 4.30 gears in the rear??? Or maybe 12" tires?? Yeah that's it, I'll bet some guy's Honda 600 is setting on blocks... :hick: That's approx what the speedo thinks you're running...

What size tires??? the stock 225/60/16 Turbo Coupe/5.0 Stang are around 25.5-26" tall... But again you'd have to have rather small rubber to throw the speedo off as much as it is...

Why has the speedo head been swapped?? 

I don't know if there is a difference in speed sensors but I don't think so... I've never had a issue swapping them around...

BTW assuming the head is out of calibration, you could swap to a 6T drive gear and be close, probably would need a 20T on the speed sensor...

BTW #2 there is a mod for head that eliminates the 85 mph limit in display, but I don't remember any details, I've always run buttstuffog...
Title: electronic instrumentation recalibration
Post by: jcassity on May 24, 2017, 01:33:21 PM
he knows i think,, its a jumper wire added to the speedo circuit card discovered by bondocougar.

w2 mod we call it
Title: electronic instrumentation recalibration
Post by: 20thanvcat on May 24, 2017, 08:19:08 PM
the cluster was swapped due to speedo light out (no numbers and printed circuit board separating ) running stock size tires (as per door sticker) 3.73 8.8 from 88 tc (disk)
I also noted tach is off (a lot) and i saw a thread about installing a resistor? but can't find it now (everyone saying there not accurate anyhow ) and want it somewhat close.
Title: electronic instrumentation recalibration
Post by: jcassity on May 25, 2017, 11:09:09 AM
you must mean the flex print / flexible circuit layers?

i found on my Coug,, not the 20th,, that the small narrow section that "enters" the bottom of the speedo had by my own doing separated and the resulting lines of tin/solder runs was cracked.

i took out the flex print, separated it apart, added small 30awg jumpers to close the gap, then wiped on some clear slicone and closed it back up,, all fixed.

this broke due to my earlier years not knowing the stages and steps involved in proper removal.
Title: electronic instrumentation recalibration
Post by: jcassity on May 25, 2017, 11:11:31 AM
i remember the resistor thing as well, i dont own a tac car , my son does though.

muddle through my evtms below,, or if you want,, search out the Master blaster's Neat  thread archived.. i think under greatest hits and near misses.

in there i believe there is a thread he did or maybe not him,, speaking ot this resistor.
Title: electronic instrumentation recalibration
Post by: TurboCoupe50 on May 25, 2017, 03:42:32 PM
Quote from: 20thanvcat;460926
the cluster was swapped due to speedo light out (no numbers and printed circuit board separating ) running stock size tires (as per door sticker) 3.73 8.8 from 88 tc (disk)
I also noted tach is off (a lot) and i saw a thread about installing a resistor? but can't find it now (everyone saying there not accurate anyhow ) and want it somewhat close.

For digital tach I dunno, has to be two versions as that cluster was used with 6&8 cyl... Scott mentions a mod, you'll have to pursue that avenue...

If you can't find a issue with cluster skewing speed, installing 23T gear should reduce error to approx 6-7% vs 13%...
Title: electronic instrumentation recalibration
Post by: 20thanvcat on May 25, 2017, 07:22:02 PM
i have copper "tape" i was going to try to repair old one - nothing to loose
Title: electronic instrumentation recalibration
Post by: TurboCoupe50 on May 25, 2017, 09:40:13 PM
Quote from: 20thanvcat;460947
i have copper "tape" i was going to try to repair old one - nothing to loose

Waste of time... If you don't make solid connections such as Scott suggested by soldering, it probably won't work and if it did there is zero chance it will last...
Title: electronic instrumentation recalibration
Post by: jcassity on May 26, 2017, 08:08:09 AM
Quote from: 20thanvcat;460947
i have copper "tape" i was going to try to repair old one - nothing to loose


if you have spare network cable or any device that is trash that has tiny wire use that.

example,, sometimes you run across old power supplies from a PC where there is a flat ribbon cable jumper of some sorts.

if i recall correctly,, and i can confirm by older pics of min,, there are about 7 runs of flex print dumping into the bottom of the speedo.

you skin/tin/flux & solder and alcohol clean then seal.

At the time i did not find any ribbon cable lying around in my bins,, and used donor material from an old network cable to obtain the "flex" 28awg jumpers which i grafted in and they are about 2'' long each.

my goal was to insure that the complete bend experienced by the flex print was now "just jumper wires".

use a magnefying glass during your work tasks,, the separation between the runs is like tighter than 1/32''
Title: electronic instrumentation recalibration
Post by: Haystack on May 26, 2017, 05:20:44 PM
Buy a speedo recalibrate  thingy. They are expensive but would fix the problem.
Title: electronic instrumentation recalibration
Post by: thunderjet302 on May 26, 2017, 09:26:35 PM
My stock, never been changed digital tachometer, is off by quite a bit: http://www.foxtbirdcougarforums.com/showthread.php?38600-The-stock-digital-tach-is-apparently-very-inaccurate&highlight=Digital+tachometer
Title: electronic instrumentation recalibration
Post by: Aerocoupe on May 27, 2017, 08:55:42 AM
[COLOR="#FF0000"]running stock size tires (as per door sticker)[/COLOR]

What does that mean?  Can you just post up the rear tire size as read off the tire?  If we assume you have a 225/60/16 then the 7/21 setup sounds about right for 3.73's but if your rear tires are not that size then we are just a bunch of monkeys at the zoo flinging poo at the visitors.
Title: electronic instrumentation recalibration
Post by: 20thanvcat on May 27, 2017, 04:48:44 PM
225/60/15 is stock for 87 20th anniversary , all of the mods are normal "mustang" mods early 90s t5, 3.73 gears 225/60/15 tires on stock rims
Title: electronic instrumentation recalibration
Post by: Aerocoupe on May 27, 2017, 04:58:17 PM
And you are 100% sure the drive gear on the output shaft of the T5 is a 7 tooth?
Title: electronic instrumentation recalibration
Post by: 20thanvcat on May 27, 2017, 05:04:30 PM
its yellow so it should be
Title: electronic instrumentation recalibration
Post by: Haystack on May 27, 2017, 05:55:57 PM
So get the black one?

6 tooth driven gear for gears higher then 3.73
https://lmr.com/item/LRS-17285A/79-98-Mustang-6-Tooth-Speedo-Drive-Gear
Title: electronic instrumentation recalibration
Post by: Aerocoupe on May 27, 2017, 06:33:15 PM
Okay, there is an 8 tooth drive gear that is a translucent yellow greenish color. This was standard in the Mustang T-5's starting in 1990. If you look at the drive gear on the output shaft through the speedo adapter hole with a flash light the 8 tooth gear will look yellow.

If this is a stock 90-93 T-5 then you have an 8 tooth drive gear. I would highly suggest you go to a black six tooth gear. The only way to verify is to pull the tail housing cover.
Title: electronic instrumentation recalibration
Post by: TheFoeYouKnow on May 27, 2017, 08:25:23 PM
Wanna hear about shaged?  I've got a full 4R70W stack in my AOD (AOD output shaft - 7 tooth, 4R70W - 8 tooth). The drive gear is machined into the output shaft.  That means that when I had a 3.27:1 I could run a purple driven gear (21 tooth), and be straight; but now I have a 3.73:1, and there is no driven gear to correct my speedo.  At all times, my speedo reads 5 to 7 MPH high depending on my speed.  I have to get a FRPP calibration box to go in-line with my OSS to correct my speed.  OR, I can build an aftermarket cluster, or buy a dakota digital VHX.  4R70W's are fully electronic normally, so to correct speedo is usually a matter of hooking up IDS and making a couple careful edits.  Not the case for me.
Title: electronic instrumentation recalibration
Post by: 20thanvcat on May 27, 2017, 08:34:14 PM
The trans was just apart to put 3rd synchro (output shaft) so I'm sure it's yellow, so the easier fix is 23 teeth driven gear, ordered one last night should be here Monday/Tuesday. the real question was if there is a different sensor for the electronic dash, since every other sensor is different i:e temp, oil pressure, and fuel. 
Because everything else seems to be in line with what Ford suggests (A T5 with a yellow 7 tooth gear should run a red 21 tooth gear if you have 3.73 gears, and 255/60/15 tires)
Title: electronic instrumentation recalibration
Post by: TurboCoupe50 on May 27, 2017, 09:20:08 PM
Quote from: TheFoeYouKnow;460979
Wanna hear about shaged?  I've got a full 4R70W stack in my AOD (AOD output shaft - 7 tooth, 4R70W - 8 tooth). The drive gear is machined into the output shaft.  That means that when I had a 3.27:1 I could run a purple driven gear (21 tooth), and be straight; but now I have a 3.73:1, and there is no driven gear to correct my speedo.  At all times, my speedo reads 5 to 7 MPH high depending on my speed.  I have to get a FRPP calibration box to go in-line with my OSS to correct my speed.  OR, I can build an aftermarket cluster, or buy a dakota digital VHX.  4R70W's are fully electronic normally, so to correct speedo is usually a matter of hooking up IDS and making a couple careful edits.  Not the case for me.

Most AOD also have the eight tooth output shaft... Generally only stuff like Super Coupe & pickups/vans had the seven tooth...
Title: electronic instrumentation recalibration
Post by: TheFoeYouKnow on May 28, 2017, 11:20:29 AM
In any case, it's machined into the output shaft, so there is no way to correct it with a gear change.  23 is as far as available gears go, and the math tells me I need 24.  I could reduce my error with a 23, but I'm told they don't hold up.
Title: electronic instrumentation recalibration
Post by: tommym on May 28, 2017, 09:53:25 PM
Ran into a problem when I rebuilt my dash using Autometer gauges. Couldn't get my speedometer to read right. Went through the calibration procedure at least a dozen times. Replaced the VSS and used a Steeda 23T gear. Ran out of patience. Finally ended up installing the Autometer GPS for the speedometer- end of problem.
Title: electronic instrumentation recalibration
Post by: Haystack on May 29, 2017, 06:45:01 AM
I varried my speedo by 11% by getting real tires. 275/60/r15. Easy overdrive adder mod.
Title: electronic instrumentation recalibration
Post by: thunderjet302 on May 30, 2017, 11:19:27 AM
Quote from: TheFoeYouKnow;460991
In any case, it's machined into the output shaft, so there is no way to correct it with a gear change.  23 is as far as available gears go, and the math tells me I need 24.  I could reduce my error with a 23, but I'm told they don't hold up.

My AOD has the 8 tooth output shaft. I've been running a 23 tooth driven gear for years without issue (the black one Late Model Restoration sells). I plan on swapping a 21 tooth back in and running the FRPP speedometer correction box at some point, but it hasn't been high on my list of things to do as of yet.