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If I purchase an instrument cluster with a tachometer that has the correct circuit print (red), will I have to do any wiring in the engine bay?
Or will the tachometer start reading right away?
That is what I did in my 83. It came with guages but no tach. From reading the threads in the sticky at the top of the forum, if your cluster came with guages it is plug and play but if it just has warning lights the process is more involved. I hope this helps.
This is the first time I have heard about the number of grounds. How exactly do I count the grounds?
I am assuming that it is where you plug the cluster in.
From the factory, the grounding is handled within the wiring harness. I installed a factory tachometer from a V8 equipped truck in the dash of my son's 1984 with 4.9L six cylinder [equipped with gauges, not idiot lights] and it worked like a charm without additional wiring.
Okay cool thanks, 1986f150six.
I purchased the entire cluster because I wanted a tach, my speedometer needle was broken, and the shift indicator assembly was not functioning.
The cluster should arrive in two days. If it doesn't work correctly, I can use the old circuit and hard wire the tach.
Thanks
One other thing, under the hood, check next to the Duraspark box for a two wire plug. It has one black and one green wire. Trucks without tach usually do not have the wiring going from this plug to the engine. If you do not have it, the green wire goes to the coil negative terminal, and the black goes to engine ground.
ill have too look at the house today after work I have the diagram but for the 8 cyl both grounds are used. otherwise how would ford use the same tack with a different number of coil pulses from the 2 different engines.
That definatly makes sense Matt. The ebay description did not clarify weather or not the cluster came from a 4.9 or 5.0.
I just found a thread... hear is the infrimation...
A V8 coil fires 33% more often than a 6cyl, or the 6 cyl fires 25% less than a V8, whichever way you want to look at it.
V8 @ 2,000 RPM = 8,000 coil fires
I6 @ 2,000 RPM = 6,000 coil fires
On the back of the tachometer, there are two grounds. One is marked with an "8" and the other is a "G". The V8 application makes use of both grounds. The 6 cylinder does not use the "8" ground. All of this is handled by the original wiring.
yea and so if the printed circuit grounds both your ok but if only one is grounded make a little 4 in jumper to connect the g and 8 and it will work for ya