Issue - Help! Dakota Digital Speed Sender

[Ron Mexico]

Hi folks

I installed my dakota digital VHX dash today and everything works fine except the speedo.
Im running a 4 speed.

The dakota kit came with an adapter for the ford transmission.

so,,, i removed the speedo gear from my old speedo wire and put it on the dakota ford adapter, then screwed in the electronic pulse generator (16KPPM), and mounted it to the transmission.

everything fit well.

Problem, when I try to calibrate my speedo, I drive one (1) mile and with a press of a button it should be calibrated. But, it seems that the speed sender is not picking up pulses as quick as it should. but anyways, eventually I picked up the minimum number of reading required to calibrate the speedo (2000 pulses) and saved the setting so I can go into a manual adjust mode - but didn't have any luck with that either as it seems the sender is not sensing enough information for calibration to work.

its a 16K PPM sender, but after driving around for what seems to be a few minutes i eventually pick up a few thousand readings. so this would NOT be enough. also when it detects the pulses from the sender its a bit erratic (i.e., slow, then fast and a random combination of the two) so this leads me to believe something is slipping mechanically in this sender and adapter. even without the speedo calibrated, my needle jumps erratically from one speed to a higher speed etc and vice versa.

I pulled everything out, checked the plastic speedo gear and it seems fine, doesn't look worn out plus its only a few months old and worked ok on my stock speedo with a speedo cable.

Im now thinking that its the actual dakota speedo sender that might be the issue, or its ford adapter to fit the transmission and maybe the marriage of these two is causing some play and some slip.

I was at it all day and eventually gave up and got hungry.

has anyone had or experienced such an issue like this with the dakota kit?

[1966stang]

Ron.

I fitted mine to a C4 and eventually got distance and then speed sorted out.

Do you have a lot of electrical interference from electronic ignition and does your Dakota have a GOOD earth?

Does the number of sped pulses increase as you drive?

[Ron Mexico]

Ron.

I fitted mine to a C4 and eventually got distance and then speed sorted out.

Do you have a lot of electrical interference from electronic ignition and does your Dakota have a GOOD earth?

Does the number of sped pulses increase as you drive?

Hi mate.

The speed pulses do increase as I drive but it's very slow.

I also tried just spinning the sender manually (without the ford adapter) and after a few turn in got something like 60 pulses. Seems I can get more pulses spinning by hand than when it's connected to the adapter and plugged into the trans.

Earth is good. No other problems with the gauges. Had an auto elec do the wiring.

[shaunp]

Are you running an MSD or electronic ignition ? make sure the trigger wire doesn't go anywhere near a plug lead or wiring to a CDI, make sure you earths are good. Just cause a sparky did it doesn't mean he did it right. I fixed an 800hp engine that the injection was false triggering due to how an expert sparky ran the wires.

[1966stang]

Ron,
Is yours the new KPH unit or MPH with KPH in the centre display?

 Not sure if they use the same sender but mine is the MPH unit and uses the original drive gear. Fitted it myself as instructions were fairly clear and only took an hour to do.

Does really sound like an earthing problem.

[Ron Mexico]

Ill trouble shoot some more tomorrow.

I'm running an MSD but the tach wire to the control box is routed down a different path than the speedo cable. But I'll check how it is behind the cluster itself but I do know that the speedo sits on zero when idling so I'm assuming it's not getting any interference from the tach.

I'll check the ground again tomorrow.

Mine is a KMH analog gauge but the senders used are universal with different adapters. It should make a difference.

[1966stang]

 ...even without the speedo calibrated, my needle jumps erratically from one speed to a higher speed etc and vice versa....

This is usually a sign of a poor earth. Check your auto elec's work, including the earth on the control module (they can make mistakes). read the instructions and follow the calibration procedure.

[Ron Mexico]

...even without the speedo calibrated, my needle jumps erratically from one speed to a higher speed etc and vice versa....

This is usually a sign of a poor earth. Check your auto elec's work, including the earth on the control module (they can make mistakes). read the instructions and follow the calibration procedure.

Thanks for the tip.

I'll check it out.

[shaunp]

Ill trouble shoot some more tomorrow.

I'm running an MSD but the tach wire to the control box is routed down a different path than the speedo cable. But I'll check how it is behind the cluster itself but I do know that the speedo sits on zero when idling so I'm assuming it's not getting any interference from the tach.

I'll check the ground again tomorrow.

Mine is a KMH analog gauge but the senders used are universal with different adapters. It should make a difference.

Not just the tach wire, any wire that has anything to do with the MSD, plug wires etc power feed.

[Ron Mexico]

Not just the tach wire, any wire that has anything to do with the MSD, plug wires etc power feed.

I've checked the wiring. It all seems ok.
I took it for another test run. To me it seems it's not collecting enough pulses.

Could it be my speedo gear ? Ie changing it to another ratio?

[1966stang]

If the gear worked ok before it should be ok now. If you are not getting the pulses correctly maybe your drive gear is not aligning correctly or has been damaged in the change.

As it is a KPH unit, which I think Dakota have just made available, have you contacted them for any advice.

[Ron Mexico]

If the gear worked ok before it should be ok now. If you are not getting the pulses correctly maybe your drive gear is not aligning correctly or has been damaged in the change.

As it is a KPH unit, which I think Dakota have just made available, have you contacted them for any advice.

Thanks Greg.

Would you be able to check if you don't mind how many pulses per mile are saved in your dakota. I think the menu item is under INFO.

[Ron Mexico]

after some more tests I think the issue lies with the actual 16k PPM sensor itself. Now this sensor is a 16k PPM (pulse per mile) so that means it should give me 16 pulses per revolution of the cable (based on 1000 revolutions of the cable per mile).

side note - i plugged in the old speedo cable and the original mechanical speedo and it worked.

Background - the speedo wire doesn't run along any power, tach, MSD or ignition leads/components, and the wiring behind the dash for where the Control Box is mounted is very neat with a custom harness and the earth is solid.

I also unplugged the sensor from the transmission and went into the menu items for auto calibration (where it shows the number of pulses detected). This is without turning the engine on, just power is on.

By hand, I turned the cable 1 revolution. this should have given me 16 pulses, instead on the first go I got 8 pulses.
Second time I got 4 pulses per revolution
Thurd time zero (0) pulses per revolution.

I span the cable 10 times and instead of it giving me 160 pulses it gave me a number in the 40's.

Then I attached a drill to the speedo gear and though I would run the drill at half speed for 60 seconds (guesstimating a few hundred rpm). This should have given me thousands of pulses. Instead it only read something like a few hundred pulses.

weird.

i also inspected the Sensor itself where the square shape "needle/cable" is - the one that rotates, it seems its got some play and doesn't feel securely mounted.

who knows... ill look into it further and wait till custommustangs opens its door on tuesday to see if they can provide feedback if they have seems this before - and hopefully get a new sensor.

also waiting for Dakota Digital to respond back to me in the next couple days.

[shaunp]

Hmm, oh well, you blokes will play with this fancy modern stuff in your old cars

[Ron Mexico]

Hmm, oh well, you blokes will play with this fancy modern stuff in your old cars

Gotta play with something 

[cap70]

I had trouble with my adapter at the start when putting the plastic gear onto the sensor it pushed the cable up inside the sensor to far so was only just sitting in the gear, and gave erratic pulses as you have.
i used some pointy nose pliers  to hold the shaft so it didnt push up into the sensor to far and made sure the square shaft actuall located inside the gear properly.
worked fine after that.

[cap70]

i also inspected the Sensor itself where the square shape "needle/cable" is - the one that rotates, it seems its got some play and doesn't feel securely mounted.

thats what i was talking about it may not be locating inside the gear properly and just getting pushed further up into the sensor

[1966stang]

Thanks Greg.

Would you be able to check if you don't mind how many pulses per mile are saved in your dakota. I think the menu item is under INFO.

Ron, mine shows 15870. That is with a 16 tooth gear for the 2.79 diff.

I used a GPS to determine 1 mile but as yours is a KPH unit I presume the odometer is also in kilometres so you need a measured kilometre rather than a mile.

[Ron Mexico]

Ron, mine shows 15870. That is with a 16 tooth gear for the 3.79 diff.

I used a GPS to determine 1 mile but as yours is a KPH unit I presume the odometer is also in kilometres so you need a measured kilometre rather than a mile.

15780, thats more like it.

Im not even getting 2000 pulses over a mile.

I've got an 18tooth driven gear on a 3.8 diff.

like i tested yesterday, i even span the sender with a drill for a minute an only collected a few hundred pulses. should have been 1000rpm x 16pulses per rev = 16,000 pulses when spinning with the drill for 60 seconds.

the sender is screwed i think (either form factory DOA, or I screwed it when putting on the ford adapter before installing on the tranny.

[TimR67]

Ive got a Dakota digital ford speed sensor in the shed, brand new, I didn't need it when I fitted the digital dash to my stang as I have a BTR electronic 4 speed auto that had its own speed sensor that worked with the dash.  If you want it I could send it to you.

[Ron Mexico]

Ive got a Dakota digital ford speed sensor in the shed, brand new, I didn't need it when I fitted the digital dash to my stang as I have a BTR electronic 4 speed auto that had its own speed sensor that worked with the dash.  If you want it I could send it to you.

Thanks Tim, you have saved the day.
ill let you know how it goes...

[Ron Mexico]

I had trouble with my adapter at the start when putting the plastic gear onto the sensor it pushed the cable up inside the sensor to far so was only just sitting in the gear, and gave erratic pulses as you have.
i used some pointy nose pliers  to hold the shaft so it didnt push up into the sensor to far and made sure the square shaft actuall located inside the gear properly.
worked fine after that.

Hi mate, I checked out what you said but mine didn't do what yours did. I just think now that it is just a dud from factory or I screwed something up when "screwing" the sensor to the ford adapter.

Ive got one on the way from Tim who was kind to send me his surplus one.

Hopefully all goes well with it.

[Ron Mexico]

anyways,

here are a couple pics of the dash installed. the night time photos don't do it justice on how it looks in real life.
amazing set of gear to be honest.





and here is the culprit that has caused me grief.

[Ron Mexico]

Big shout out to TIM sending me his sender.
Speedo works like a charm now. Smooth as silk and dead accurate.

My sender was DOA.

Cheers
Ronny

[TimR67]

No worries.  Ive got the older digital dash from Dakota, I luv it.  The purists dont like them but I dont give a stuff, I built my car to please me.