I have found a junked 96 Dakota. I am trying to find out if the gage package is interchangeable with a 87. I would like to keep my speedometer, but would like to use the tach, and move the gas gage over to the top right. Does anyone know if this is possible? Thanks

 

The tach is driven off the ECU, and therefore won't do any good on the 1987 without some working. Is your '87 a 4 or a 6 cylinder?

For 1996, IIRC, the instrument cluster is all-electronic and driven off the ECU, so no, they won't swap. However, I will freely admit that I may be wrong there. It's fairly easy to check - if you have a cable going to the back of the speedometer from the transmission, I'm wrong, and they'll swap (save for the tach).

RwP

 

Hey Ralph, Thanks for posting. Mine is cable driven. I found a wrecked 96 with a 5.2 4wd and automatic. I was wanting the dash for the tach but what you told me is what I suspected. Currently mine is the v6.
Do you know if any of the earlier dash's with a tach will work on the 87 or will all of the tachs be dependent on a ecu input? Currently mine has gauges (water temp, volts, oil,) but no tach. I don't think a tach was offered in 87, at least I cant find it in my FSM.
And again, I want a tach for a 8 cyl. motor.

 

All I find in the Gen1 manuals I've bought and downloaded (hint: There's stickies here!) shows the tach being ECU driven, two pulses per revolution. *dry* This is rather hard to fake on a V6 */dry*, although it's possible with some logic circuitry (a x2 and a /3 pair should get it, but since I have NO idea what the waveform looks like ... )

For a V8, if we can find the waveform and if I'm lucky and it's just a square wave, a /2 flip flop SHOULD be able to generate acceptable waveforms ...

Guess I'm going to have to find a running vehicle with the tach, and get my o'scope on the line to see what it looks like.

Yah, I'd like to have a tach also. Worst case, it's time to set up the PCB layout software and make a new cluster to fit where the old one is ... using, say, Autometer or Stewart-Warner gauges.

RwP

RwP

 

Maybe this is a dumb question... But... Shouldn't the sensor input to the computer be the same between a 6 and an 8? Even though the cylinder count differs by two, rotational speed at the crank is the rotational speed at the crank?

 

I would absolutely love to get a tach in my 1990 V6. I know there was one offered in the cluster in '90 but I need to sit down and dig through the wiring schematic to figure out what it takes to put one in a factory non-tachometer truck.

 

Why, yes. But how do you get the tach signal if it's not generated by the ECU?

Usually, it's by watching coil events. Once per cylinder firing. Which is 3 times for a V6 per revolution, 4 times for a V8.

And the Dakota tach wants 2 pulses per revolution.

The ECU just does the digital math to generate 2 pulses per revolution off the distributor pick up on our older motors.

RwP

 

i have a 92 3.9 dak and have a tach on mine it should be as simple as looking at the wiring diagram on the ecu and the cluster and finding the tach wire and connecting it at least that worked on rams when converting to deluxe cluster

 

Robert Young - Might not even have to do that much work, it may already be connected on the 1992. However, on the 1988 (until late in the model year), the ECU didn't output a tach signal. *dry* It's kind of hard to wire it up when it ain't there.

RwP

 

Ralph, what is your opinion of this adapter.
http://www.dakotadigital.com/index.c...rod/prd127.htm


My truck has a carb motor from the factory and again when I convert to a v8 I plan to stay very basic. IE carb and a standard mopar electronic ignition.
Thanks