Speedometer Calibration?

[markf]

My 1995 Wrangler has the New process 231 J Transfer case with an electric speed sensor (no gears to change)

The speedometer is off by 9-10 mph.

Any advice on calibration would be appreciated.

 

[machoheadgames]

My 1995 Wrangler has the New process 231 J Transfer case with an electric speed sensor (no gears to change)

The speedometer is off by 9-10 mph.

Any advice on calibration would be appreciated.

Take a picture of that. 92-95's are still gear driven from the factory, they just spin an electric sensor rather than a cable. Unless your PO upgraded you to a super short SYE, in which case they give you a non adjustable Honeywell speed sensor from a Rubicon TJ. A pic will clarify. If it turns out that you have the non adjustable sensor, I can help you find a converter that will correct the speed signal to the speedometer as well.

 

[markf]

Take a picture of that. 92-95's are still gear driven from the factory, they just spin an electric sensor rather than a cable. Unless your PO upgraded you to a super short SYE, in which case they give you a non adjustable Honeywell speed sensor from a Rubicon TJ. A pic will clarify. If it turns out that you have the non adjustable sensor, I can help you find a converter that will correct the speed signal to the speedometer as well.

Have the sye installed by the previous owner when the 2.5 Rubicon Express lift was installed. Tires are BFG Mud Terrains LT 255 /75R17

 

[Chris]

I'm confused. To my knowledge all 231 transfer cases had gears, and it was only the 241OR Rubicon transfer case on the TJs that had the electric speed sensor and therefore required one of these:

In this case that I am wrong, this is what you'll need:

SpeedoHealer v4 (SH) - HealTech Electronics Ltd.

The SpeedoHealer v4 (SH) is the best speedometer and odometer calibrator on the market. Available with bike specific and universal harness kits.

www.healtech-electronics.com

Those things work amazing, and they are plug-and-play. Took me all of 10 minutes to install and get calibrated on my TJ Rubicon.

 

[machoheadgames]

I'm confused. To my knowledge all 231 transfer cases had gears, and it was only the 241OR Rubicon transfer case on the TJs that had the electric speed sensor and therefore required on

All NP231s come from the factory with gears. Super Short SYEs like he showed us make the transfer case so short that it eliminates the gear because there is no longer room for it.


To be annoyingly technical, speed sensors from 1991 and later are ALL electronic on Wranglers. The old CJs used mechanical speed sensors that spun a cable which spun the speedometer. The YJ continued trend from 87-90. The 1991 YJ brought out the MPFI 4.0 and 2.5. The PCMs needed speed signal as a result. The 1991 model still had the older dash. So for 1991, a hybrid sensor combined a speedo cable adapter with an electrical signal generator. The signal was sent to the PCM and the cable still spun the speedo.

1992 brought out a new dash gauge arrangement with an electrical speedo. No more speedo cable. This speed sensor still used a gear, it’s just the gear spinning the speed sensor generates an electrical signal which is sent to the PCM and the speedo. The speedo raises the needle accordingly.

Early 1997 TJs used the same sensor as 92-95. Late 97 switched over to the new style because the plug connector on the 97 and prior style leaked ATF up from the transfer case which would get into the electrical contacts. They fixed that for the late 97 speed sensor and all NP231s for the rest of the TJ had it. They were all still electrical though. The Rubi reports the same thing but since it’s just a fixed sensor, it needs a calibrator. The exact same calibrator can be installed on speedo gear Jeeps. It will still recalibrate the electrical signal it receives from the speedo gear input exactly the same.

All that said, Speedohealer doesn’t make Jeep harnesses anymore, so that’s less of an option unless folks want to make their own wiring harness. I would recommend a Dakota Digital since Blue Monkey stopped selling the Speedohealer kits for Jeeps.

 

[Chris]

All that said, Speedohealer doesn’t make Jeep harnesses anymore, so that’s less of an option unless folks want to make their own wiring harness. I would recommend a Dakota Digital since Blue Monkey stopped selling the Speedohealer kits for Jeeps.

That's a bummer! I had a Blue Money setup with a plug-and-play harness, and it was one of the easiest things to install and configure. Does Dakota Digital sell a plug-and-play harness?

Not that I mind wiring, but whenever I can get a clean, plug-and-play installation, I'll always go for that.

 

[machoheadgames]

That's a bummer! I had a Blue Money setup with a plug-and-play harness, and it was one of the easiest things to install and configure. Does Dakota Digital sell a plug-and-play harness?

Not that I mind wiring, but whenever I can get a clean, plug-and-play installation, I'll always go for that.

Yeah the Blue Monkey version of the healer was awesome. I had one until my build plan changed and I returned it. They closed about a week after that. I still have no idea why they closed, it was literally one day they were selling and the next they were all closed up and never to be heard from again.

I think you can buy a generic harness for the speedo healer and splice in the wires but that’s not nice and plug and play for most. I personally would not be bothered by that but I am pretty equipped for electrical wiring work.

The Dakota Digital is not plug and play either and neither are the other two options, Yellr’s Yellow Box or Superlift’s Tru-speed.

Hell, maybe I should go into the business of buying speed sensor connectors and making plug and play harnesses for various lengths for installation locations as well as different connector styles for the various units people will use. Lol. It’s easy enough, just most don’t want to or don’t know how to do it.

 

[markf]

Thanks to everyone. The Dakota Digital SGI-100BT: Universal Speedometer and Tachometer Interface looks pretty sweet.

 

[machoheadgames]

Thanks to everyone. The Dakota Digital SGI-100BT: Universal Speedometer and Tachometer Interface looks pretty sweet.

Looks cool, although unnecessary. Your tach should be fine as is unless something is inherently wrong with it. Just calibrating the speedo is really all ya need.

 

[Walt Jaquith]

I just used the Dakota Digital unit on my project. A little pricey, but it worked great and was easy to set up. Even has some diagnostics if you load up the phone app.

 

[markf]

Nice. Where did you mount it and tap into the wires?

 

[Walt Jaquith]

Mine's not stock anymore so my specifics won't help you, but you'll want to mount the DD unit close to the fuse panel under the dash. I put mine on a plate with 3M double-sided foam tape, but it has regular mounting lugs as well.

You're looking for a white wire with an orange stripe coming through the firewall behind the fuse panel, and heading to the instrument cluster. That's the speed sensor feed to the speedometer. I found it at both ends, cut it fairly close to the instrument cluster connector, and pulled it out of the loom, using it to fish another wire in. That left me plenty of wire to get to the SGI-100BT, and I only had to make the one splice of the new wire up by the cluster connector.

Also , the buzzer module is mounted to the bottom of the fuse panel. The dark blue/white wire that connects there is a power feed from the ignition switch, and the black wire is a chassis ground. Good place to tap for both of those.

 

[Chris]

Yeah the Blue Monkey version of the healer was awesome. I had one until my build plan changed and I returned it. They closed about a week after that. I still have no idea why they closed, it was literally one day they were selling and the next they were all closed up and never to be heard from again.

I think you can buy a generic harness for the speedo healer and splice in the wires but that’s not nice and plug and play for most. I personally would not be bothered by that but I am pretty equipped for electrical wiring work.

The Dakota Digital is not plug and play either and neither are the other two options, Yellr’s Yellow Box or Superlift’s Tru-speed.

Hell, maybe I should go into the business of buying speed sensor connectors and making plug and play harnesses for various lengths for installation locations as well as different connector styles for the various units people will use. Lol. It’s easy enough, just most don’t want to or don’t know how to do it.

Ha, you might be able to make some money off of it. I'm actually really good wiring wiring myself, but when it comes to some stuff, I'm just lazy. If someone told me I could get a plug-and-play harness for $40, I'd probably pay it just for the convenience factor alone

 

[BBClamper]

Macho, once again, your a fountain of information! I need your help on this one….,I’m going with Auto Meter Pro Comp series in my new Double D dash. The speedo claims to “work with most 2 wire sine wave or 3 wire Hall effect set ups” will this work on my 92 YJ?

 

[machoheadgames]

Macho, once again, your a fountain of information! I need your help on this one….,I’m going with Auto Meter Pro Comp series in my new Double D dash. The speedo claims to “work with most 2 wire sine wave or 3 wire Hall effect set ups” will this work on my 92 YJ?

Should be fine. Your 92 is a 3 wire Hall effect. A 91 would have been a 2 wire reed switch but it spits out the same speed signal as the 3 wire hall. So I’m sure you should be fine. Can you post the speedo instructions for what you’re buying?

The 92-95 3 wire speedo is an 8v power supply to speed sensor from PCM, sensor ground, and a 3rd wire that the sensor pulses to provide speed feedback back to the pcm and the gauge. I would imagine that third wire is the one providing speed input to your new autometer gauge.