Electronic gurus? KJ 8.25 rear diff tone wheel wiring.......

JJsTJ · **Posted:** Tue Aug 07, 2007 8:42 pm

I (and others) am looking to figure out how the KJs computer sees the signal that comes from the rear diff tone wheel that tells it vehicle speed, etc.

We need to figure out how to fool the KJ into thinking the signal from a Rubicon transfer case is coming from the rear diff. The rubicon transfer case uses a 3 wire system that has 5 volt wire, ground and signal. The KJs diff tone wheel wiring is only 2 wires and I need to figure out how it works and how to change it to work w/ the Rubi case.

Whoever can come up with a way to make this all work will be a hero as there are folks needing this info for their SFA swaps using rear diffs other than the 8.25 and running non-stock transfer cases.

HELP!?

Please?

tjkj2002 · **Posted:** Tue Aug 07, 2007 9:01 pm

JJsKJ wrote:

I (and others) am looking to figure out how the KJs computer sees the signal that comes from the rear diff tone wheel that tells it vehicle speed, etc.

We need to figure out how to fool the KJ into thinking the signal from a Rubicon transfer case is coming from the rear diff. The rubicon transfer case uses a 3 wire system that has 5 volt wire, ground and signal. The KJs diff tone wheel wiring is only 2 wires and I need to figure out how it works and how to change it to work w/ the Rubi case.

Whoever can come up with a way to make this all work will be a hero as there are folks needing this info for their SFA swaps using rear diffs other than the 8.25 and running non-stock transfer cases.

HELP!?

Please?

This is my plan of attack---http://www.dakotadigital.com/index.cfm/page/ptype=product/product_id=126/category_id=287/home_id=59/mode=prod/prd126.htm----.Since I don't have ABS I'll be suppling the TJ speedo sensor with the PCM 5 volt signal from the ABS,hook up the other 2 wires(ground,signal) to the existing speedo wires(from rear diff) and use that signal interface to dail in the correct speedo setting,I still need to find out the PPM(pulse per min) of the TJ sensor and the PPM of the KJ sensor to see if it will actually work right,let you know in a few months.

2nd plan of attack is to use one of the VSS in my 45RFE tranny to operate the speedo.

OPPS!!!!!!!!!!! Top Sercret stuff,for SFA'ers eye's only!!!!! :lol:

EDIT:::Just started my med board today so hopefully in 3-5 month's my KJ will be SFA.

JJsTJ · **Posted:** Tue Aug 07, 2007 9:33 pm

tjkj2002 wrote:

JJsKJ wrote:

I (and others) am looking to figure out how the KJs computer sees the signal that comes from the rear diff tone wheel that tells it vehicle speed, etc.

We need to figure out how to fool the KJ into thinking the signal from a Rubicon transfer case is coming from the rear diff. The rubicon transfer case uses a 3 wire system that has 5 volt wire, ground and signal. The KJs diff tone wheel wiring is only 2 wires and I need to figure out how it works and how to change it to work w/ the Rubi case.

Whoever can come up with a way to make this all work will be a hero as there are folks needing this info for their SFA swaps using rear diffs other than the 8.25 and running non-stock transfer cases.

HELP!?

Please?

This is my plan of attack---http://www.dakotadigital.com/index.cfm/page/ptype=product/product_id=126/category_id=287/home_id=59/mode=prod/prd126.htm----.Since I don't have ABS I'll be suppling the TJ speedo sensor with the PCM 5 volt signal from the ABS,hook up the other 2 wires(ground,signal) to the existing speedo wires(from rear diff) and use that signal interface to dail in the correct speedo setting,I still need to find out the PPM(pulse per min) of the TJ sensor and the PPM of the KJ sensor to see if it will actually work right,let you know in a few months.

2nd plan of attack is to use one of the VSS in my 45RFE tranny to operate the speedo.

OPPS!!!!!!!!!!! Top Sercret stuff,for SFA'ers eye's only!!!!! :lol:

EDIT:::Just started my med board today so hopefully in 3-5 month's my KJ will be SFA.

Few months?! I need to get this figured out in a couple months or less.
I just ordered the interface unit. :wink:

Guess I will be the guinea pig on this one.

JJsTJ · **Posted:** Tue Aug 07, 2007 9:39 pm

Anyone out there that can read THIS MANUAL for the above mentioned unit and decipher if this is going to work?

tjkj2002 · **Posted:** Tue Aug 07, 2007 9:41 pm

I would be the guinea pig but I have to wait till my med board is complete and I get my big fat severence pay check(what do you think I'm using to finaince the SFA),and USAFCOP is 1st in line :cry:

(oh well,better to get the bugs worked out,plans all worked out,and I can't go to long without my KJ since it is my DD).

I'm about 95% positive that signal interface will work,just need to feed the TJ sensor with a 5 volt supply from the PCM(very easy,all the PCM sensors except the O2 sensors have 5 volts going to them) and then hook the ground up using the original KJ VSS ground,and then hook signal interface between the signal wires and adjust.Sounds simple enough,it's just proving hard to find the PPM of the TJ and the KJ VSS.

tjkj2002 · **Posted:** Tue Aug 07, 2007 9:45 pm

JJsKJ wrote:

Anyone out there that can read THIS MANUAL for the above mentioned unit and decipher if this is going to work?

The biggest thing is to find the PPM of the TJ and the KJ VSS,then you will now how(what wires) to hook up to,that unit can be used to convert a ton of signals,you just need to now what PPM going in and what PPM needs to come out.

USAFCOP · **Posted:** Tue Aug 07, 2007 9:50 pm

Well JJ, please let us know what happens... Like Troy said, Mine is starting as soon as the trails are closed.

JJsTJ · **Posted:** Tue Aug 07, 2007 9:58 pm

Well, I feel better about it then. I am a nervous wreck when it comes to messing w/ electronic stuff especially car computers, etc. I don't want to let the smoke out of the wires! :shock:

DaveKJ02 · **Posted:** Tue Aug 07, 2007 10:08 pm

Do you have a SM, or at least the wiring section for a Rubi? You're most likely going to need the interface since the KJ wires run to the BCM and I'll bet you'll need PPM's calibrated. I dont know which is the signal on a Rubi TC, but on the KJ it's the Yellow/DarkBlue.

There used to be a link somehere here to free online mauals. If you get me the Rubi's schematics, I may be able to help you.

JJsTJ · **Posted:** Tue Aug 07, 2007 10:13 pm

DaveKJ02 wrote:

Do you have a SM, or at least the wiring section for a Rubi? You're most likely going to need the interface since the KJ wires run to the BCM and I'll bet you'll need PPM's calibrated. I dont know which is the signal on a Rubi TC, but on the KJ it's the Yellow/DarkBlue.

There used to be a link somehere here to free online mauals. If you get me the Rubi's schematics, I may be able to help you.

Thanks, I am working on it. I am on a mission to get this figured out ASAP.

tjkj2002 · **Posted:** Tue Aug 07, 2007 10:21 pm

TJ VSS----

Ground-Bark Blue/Dark Green

5 Volt power supply-Yellow/Pink

Signal-Dark Blue/Orange

KJ VSS----

Signal-Yellow/Dark Blue

12 power-Yellow

Gris · **Posted:** Wed Aug 08, 2007 10:04 am

Just curious...

Why do you need to change where the speedo signal comes from at all? Just to be able to corret it for larger tires and such?

Wouldn't a resistor inline with the stock sensor work to adjust the signal?

then again, if you could get that $80 gizmo to readjust what the engine is seeing, and return some of the power that it's clamping down on because of the larger tires, I'd be game.

JJsTJ · **Posted:** Wed Aug 08, 2007 10:26 am

Gris wrote:

Just curious...

Why do you need to change where the speedo signal comes from at all? Just to be able to corret it for larger tires and such?

Wouldn't a resistor inline with the stock sensor work to adjust the signal?

then again, if you could get that $80 gizmo to readjust what the engine is seeing, and return some of the power that it's clamping down on because of the larger tires, I'd be game.

This is for a SFA swap when not using the factory 8.25 rear that picks its signal up from a tone wheel on the carrier. I, and others, are using Rubicon transfer cases or aftermarket cases that pick up their speedo signal from inside the transfer case. The possible ability to dial-in/ correct the speedo will be nice too.

This will eventually get moved to the SFA section but is here for exposure to those electronics knowledgeable members.

wildrussian · **Posted:** Wed Aug 08, 2007 10:42 am

read about it some and wonder what the heck is SFA and what it stands for?

WoodysKJ · **Posted:** Wed Aug 08, 2007 10:56 am

SFA: Solid Front Axel

carroll952 · **Posted:** Wed Aug 08, 2007 1:51 pm

JJ, that SGI looks like it'd do the trick. Judging by the descriptions for each application It sounds like the TJ VSS follows alot with application 2. Of course it'd be great to find out exactly how many PPM is being sent out.

Has anyone tried calling Jeep and seeing if they could find out? The regular techs probably won't know but someone's bound to be able to look up the specs for it. Of course that's probably easier said than done.

You can always try trial and error :wink:

On the bright side adjusting it to make the speedo accurate seems pretty easy.

You could also calculate the PPM using an oscilloscope.

Justin

Rockjeep · **Posted:** Wed Aug 08, 2007 2:42 pm

Man, If we only knew someone up there in big bear who had an electronics company. Would be cool if they were electrical engineers who designed custom electronics and might be interested in helping out. If there only was a company like this up there. :roll:

Oh wait there is. Me you dummy. I'd be glad to help out. We need to get stock reading on both the kj and rubi. It might be as simple as stepping down the voltage to 5v. Pm me so we can talk. I'm sure there is someting you have access to that I would be willing to trade work for.
Kory

JJsTJ · **Posted:** Wed Aug 08, 2007 3:02 pm

Kory, HOw come I am working on this then w/ your ties to All J's!?!? DUUUHHHH!!!! :roll:

Sheesh!

I am sure we can work something out but you would be doing a service for not only me but every SFA (or rear diff swapper) wanna be after me AND All J's. It sounds like we will have this figured out no problem.

BTW, I had no idea what you did for a living. I thought you were in construction. :wink:

Rockjeep · **Posted:** Wed Aug 08, 2007 3:13 pm

i live life on the down low.

ARBSeth · **Posted:** Wed Aug 08, 2007 5:36 pm

JJ,
If you're that worried about it, I'll get off my stupid and wire the darn thing up already.
I just don't mind the missing speedo for before mentioned reasons, but the ring is already in the D44 Diff... All I need to do is drill the housing for the old KJ sensor, set the depth correctly and reconnect the wires Quinn cut when we tried to pull it off the Tera sensor. I was waiting until our D44 diff covers showed up so I didn't have to reseal the damned thing again just to swap the covers, but if you're that stressed, I'll just knock it out and see if it works.
I honestly don't see any reason why the ring out of the Isuzu won't work with only 3 more teeth on it... it fit right on the RD116, and it's made from the same material, so the signal should be fine, although you'd have to lose the POS Detroit you have now

Thoughts from Kory?

Electronic gurus? KJ 8.25 rear diff tone wheel wiring.......

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