97 k3500 Chummins speedo

Cornbread1

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Jan 23, 2012
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97 4x4 p-pump cummins swap, no computer in truck, dodge 4500/241, D80 rear, factory gauges, I have the factory gauges working except for the speedo. No computer or engine portion of the harness left in the truck. Looking for creative ideas anybody might have?? I've talked to Dakota Digital and they say they "think" they have what I need..... A converter box that will convert between the speedo signals used in vehicles but I'm not completely sure how it would work since I'm not running a computer anymore. I know Chevy uses 4000 ppm for the speedo, but not sure exactly witch signal or the signal for dodge? I know I know "search" And I have, but not finding the info I need, so if anybody has any suggestions then I'm all ears! :) this is not a major issue by any means, just be nice to have the speedo workin for mpg figuring and things. I have gps I use but we all know there's glitches and tweaks so the odometer part isn't that reliable lol. I posted this in GM tech section also (not for sure the best place for it) Thanks for any help.
 
Sorry, guess that would be some needed info, it was a 454/4l80e/4x4 combo. I stripped it of all running gear and started over. I cut all the harness out except for the fuse box and plug to plug back into firewall. Basically just cut the engine stuff out, then hooked up wires back to factory oil,water,fuel.
 
im putting a 12 valve in a 95 chevy right now and thinking about that same problem i will be checking in to see the fix what did you do for a tach
 
did it have a 241 tc before, or a borg?that is where the Speedo gets its input.
 
I'm not sure if it would work, but you may try hooking up to the RWAL sensor in the D80, and run it to a VSSB with the dip switch mod done to it. Then see if you can set the dip switches in it to get the speedo to read correct. I don't know how many teeth the ring gear mounted tone wheel in a D80 has, but I know the GM transfer case used a 40 tooth wheel.
 
im putting a 12 valve in a 95 chevy right now and thinking about that same problem i will be checking in to see the fix what did you do for a tach

Good deal, I haven't done the tach just yet, I have it figured out, just haven't done it. I'm either gonna use a 4-pin GM HEI ignition module with a magnetic pick up on the four bolts of the harmonic balancer, or use the Dakota Digital kit that you put a pick up in the flywheel housing that uses the flywheel teeth. I want it to be trouble free and as accurate as I can. I just don't like the alternator idea.
 
did it have a 241 tc before, or a borg?that is where the Speedo gets its input.

Yes, it had a 241 in it, but I sold all the old stuff to a buddy. I have access to another tail housing that I'm gonna see bout changing out and tone ring. The input is not where I'm having trouble, it's the communicating between there and the speedo.
 
Could of used a Trans setup like I did in mine and used the gm transfer case. I had a gm nv4500 with a dodge bell housing and input shaft. I maintained all the gm sensors in mine. The alternator is where the tach signal comes from. Search on here I posted the part numbers on here to do the one wire conversion on the cummins alternators.
 
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I'm not sure if it would work, but you may try hooking up to the RWAL sensor in the D80, and run it to a VSSB with the dip switch mod done to it. Then see if you can set the dip switches in it to get the speedo to read correct. I don't know how many teeth the ring gear mounted tone wheel in a D80 has, but I know the GM transfer case used a 40 tooth wheel.

I have thought about that, it's what I had talked to Dakota Digital about and the guy said he was not 100% sure, but he thought the box they have would work, run the two wires from that sensor to the box, then from the box to the speedo, then calibrate with the dips. He said the box will convert from square to sign wave, and visa versa. It would also change an extreme amount if needed. He said they originally designed the box to be used for changing the speedo after tire or gear changes without having to program the computer. I'm not sure if that will work or not, I've searched a bit and haven't figured out the signal that dodge uses, or the pulses on the tone in the d80.
 
Could of used a Trans setup like I did in mine and used the gm transfer case. I maintained all the gm sensors in mine. The alternator is where the tach signal comes from. Search on here I posted the part numbers on here to do the one wire conversion on the cummins alternators.

What setup did you run? I ran the dodge stuff cause I got a smokin deal on it all. $1,700 bucks in motor, tranny, tcase, front and rear axles, exhaust, d shafts and clutch stuff :)
The one wire alternator deal..... That where you getting you tach from? Thanks
 
Sorry, dumb question on the tranny, got two screens goin here tryin to do some dealing ond parts and forgot about reading what you had lol.
 
I used a gm nv4500 that bolted right to my transfer case just put a dodge bell housing and input shaft in it. The one wire alt setup I had a signal wire run off it to hook the tach signal wire up to. First time around with it we made a bracket to hold the gm alt then I put a cummins one and tensioner.
 
Sweet deal, how long you been running that tranny setup? You have yours "turned up"? I ask cause I had talked to a guy once when I got started and he told me that the GM prolly wouldn't hold up as well to the CTD. I haven't fooled with them enough to know much bout them. I'm gonna be using my truck to pull a 48ft tri-axle "crawler hauler" that's gonna have a 24ft living quarters and 16ft flat for my big jeep that has 49" iroks and 4wheel steer Rockwells so it's gonna be a pretty heavy animal lol. So doin that, I'm actually looking for an RTO-6610 to put behind it with a divorced tcase.
On your alt, does it work the tach fairly accurate? I've heard and read a lil bout them but just haven't exactly understood how it works. How did you do yours?
 
Well it's a bit of an old thread but I did get the speedo working and I done it by using the Dakota Digital SGI-5 interface and ran a 2-wire cord from the pick-up on the D-80 rear to the SGI-5 input and then a single wire directly to the speedo. I cut the signal wire behind the I/P at the plugin and hooked to it there. Set the dip switches and got speedo moving, then started driving the truck with my gps on and used the "up" and "down" buttons to dial the speedo in and it is dead on accurate!!! Sensor--SGI5--speedo and no computer. Works excellent for 2+ yrs now!


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was thinking of trying a Dakota box with my f550 to make the speedo work without the anti-stop brake system cool to see it works using the rear axle signal wires.
 
was thinking of trying a Dakota box with my f550 to make the speedo work without the anti-stop brake system cool to see it works using the rear axle signal wires.


It should work for you no problem, it does a fantastic job in my truck! I believe it would work with about any signal you give it. Just a matter of setting the dip switches right then using the up and down to fine tune it in :)


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Im using the Dakota Digital with the dodge speed sensor hooked up where the DRAC module used to be.Its a little glitchy at 45mph but works great. Rich
 
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