tach help

[racsan]

94 2.3, put a aftermarket tach on, reading 1/2 or less than what it should. When I put a tach on my 92 2.3 I didnt have thisproblem, could I have a bad tach or did the signal wire change?

 

[fastpakr]

I done have an answer for the tach you added, but for what it's worth you can swap an explorer cluster in with a factory tach and it works with no alteration.

 

[tomw]

rascanascar ... Is it possible you need to set a jumper or switch inside the tach housing to set the number of cylinders? Many are set to indicate for 8 cylinder engines, which would match the condition you report, being half the number of pulses per each rotation of the crankshaft.
tom

 

[racsan]

Switch on back is set to 4. Tried a 2nd new tach and is doing the same thing.

 

[tomw]

If you have the 8-plug head, you may be hooked into the wrong signal, as an absolute guess.
If you have the 'waste' spark system, you'll get double firings of the plugs, as two will fire at the same time. Again, doubling the spark fire rate.
Did the instructions point you at a particular wire to connect for tach reading?

FWIW, if the ignition system changed between 1992 and 1994, then you indeed may be connecting to the wrong wire. I do not know which wire is appropriate, I have only one coil, and that's where I am getting my signal.
Maybe you could check with your local library to see if they have access to wiring diagrams which would indicate the tach connection for the factory unit. I think Autozone or Advance has access to wiring diagrams if you 'join' or sign up for a 'membership'.
tom

 

[racsan]

ive tried diffrent wires, all with the same amount of no-luck. what would need modified to use a explorer cluster? no explorer came with a 2.3, i think they were all 4.0's except for the all-wheel drive 5.0 V8. finding a 94 explorer will be diffficult, and not sure how new i can go.

 

[racsan]

ok, update- i was under the hood today and noticed a wire in the harnes plugging into the bottom of a module was cut somehow, it was a tan with peach coloerd stripe, tried to figure out what wire that was online but couldnt, spliced it back together with a connector. when i had the plug off the module i also found a black wire not connected to anything, seemed to not have a place to go to. i extended it and ran it to a chassis ground as that seemed a logical place for a black wire to go to. on a hunch i hooked my green wire back up for the tach, it does work now, engine doesnt run any diffrent. im wondering if the cut wire was for something related to the intake side spark plug coil pack. still starts and runs just the same as it did before, not sure why wire was cut, hard to say as im not the original owner and theres been a few other odd cobbled up things ive found since i got this. (like the fuel tank being held up by a nylon securing strap on one end, and the other end using steel plumbers tape)