2001 Tachometer Problem

tdart · Feb 15, 2010

Hey guys,
Lets say I put a different motor in my '01 that had a 4.7 L in it, and I want to make the factory tach work. What do I need to imitate? crank sensor, cam sensor, or possibly input speed sensor in the transmission? I can see how any these could be used to calculate rpm, but what does the truck use?

Thanks for your expertise.

Misfit · Feb 15, 2010

Well, what motor did you put in it?

tdart · Feb 15, 2010

A four cylinder cummins.

caulk04 · Feb 15, 2010

I wouldn't be surprised if it was something that worked through the PCM and was transmitted over the BUS network to the gauges.

Check out the troubleshooting forum here, you can download a factory service manual ('02 should be the same) that will help you out.

jmaack727 · Feb 15, 2010

I think we need pix of your swap. Sounds cool.

nascarneil100 · Feb 15, 2010

pics?

tdart · Feb 17, 2010

Here you go:

http://www.4btswaps.com/forum/showthread.php?12195-2001-Quad-Cab-Dakota-2wd&p=99865#post99865

I know it s a bus thing with the instrument cluster that makes the tach work, but I'm wondering what the computer uses to determine rpm. I think I'll start by hooking up the Crank Position Sensor and see if that works. Anyone ever have that sensor unplugged or bad and notice the tach not working? I have the 2001 repair manual, but it doesn't go into detail here.

Thanks for your help.

69rrbruce · Feb 17, 2010

What year is the cummins and which computer are you using? I know that the 2001 and newer have a 1 wire PCI Bus system and the 2000 and older have a 2 wire CCD bus system. The computer and the gauge cluster have to be from the same vintage or they won't talk to each other.

tdart · Feb 17, 2010

69rrbruce said:
What year is the cummins and which computer are you using? I know that the 2001 and newer have a 1 wire PCI Bus system and the 2000 and older have a 2 wire CCD bus system. The computer and the gauge cluster have to be from the same vintage or they won't talk to each other.

Its a completely mechanical engine, no computer. The computer is the original '01 v8 computer.

69rrbruce · Feb 18, 2010

tdart said:
Its a completely mechanical engine, no computer. The computer is the original '01 v8 computer.

That computer would provide the signal to the tach based on input from the new engine and thats your question "where does that input come from?" It could be distributor signal, coil signal, injector signal, cam sensor, crank sensor, etc.You might want to compare the engine wiring harness wiring diagrams from both engines for any clues. Connect the output signal from the new engine to the input wire on the existing computer. Sounds simple...NOT....good luck.

2001 Tachometer Problem

tdart

Misfit

tdart

caulk04

jmaack727

nascarneil100

tdart

69rrbruce

tdart

69rrbruce

Top Contributors this Month

Recommended Communities