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Discussion Starter #1
Could anyone tell me why the Sunpro Supertach 2 -CP7901 will not function in my 92 Corolla with a 4AFE engine? I followed all of the directions and the red wire is to the positive and the black to the negative and the green to the -G at the diagnostic terminal. Is this tach simply not compatible with this engine? At first the needle just dipped a little bit and now it waits for 30 seconds or so and then proceeds backward to 8000rpm and sits there till I turn off the engine. I sure need some help on this one.
Thanks,
KFL
 

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Homer Lusk Collyer
AE92
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1,144 Posts
I don't know about that tach specifically and I'm too lazy to look it up right now... but when I put a stupid ricey tach on my brother's 20R-powered RV, I just connected it to the coil and set the toggle switch to 4 cylinders. I'd try that instead of the diag port and see if it works then.
 

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Discussion Starter #3
I do not think there is a coil as such as I think there are coils, or igniter's and I do not entirely understand the arrangement at the moment and the Hayes Book I have is tough to research as the indexing is so terrible. It is very difficult to find things. I have fuel injection and that goes with an entirely different interactive ignition system. I have tried to access it in a number of places to no avail. Sunpro is a well recognized reliable tach according to my sources. I set it on 4cyl to begin with. I am really not all that familiar with various ignition systems but this arrangement is somewhat different.
What is ricey? You said there is a place where this can be looked up?
Thanks,
KFL
 

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coil is internal to the distributor.... has an epoxy top... has 2 wires, brown and black... the black wire will have your tach signal... use a shielded cable to ensure no interference.
 

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Discussion Starter #5
I tried both of those wires yesterday to no avail and I will go out and experiment again tomorrow. The factory said basically the same thing about the 2 wires. I will have to try it on another motor to see if it is the tach. It does not seem that it would be but?
Thanks so much for the help.
Later.
KFL
 

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92 Toyota corolla DX
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Ok I just finished putting mine in. The red wire to the engine main fuse in the engine bay fuse box. This way you dont burn up the battery or your tach. Then the black wire goes to the ground somewhere... Then the white cable is the backlight this can go to the headlight fuse that is under the hood as well. Now the green wire. Look at you distributer cap you should see about 5-6 wires red,blue,green, all those. The wire you want goes to the lone black wire on the distributer it is on the far right side of your distributer. I'll post a pic in a few minutes. But that's what you want no coils no nothing just that wire.
 

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Ok I just finished putting mine in. The red wire to the engine main fuse in the engine bay fuse box. This way you dont burn up the battery or your tach. Then the black wire goes to the ground somewhere... Then the white cable is the backlight this can go to the headlight fuse that is under the hood as well. Now the green wire. Look at you distributer cap you should see about 5-6 wires red,blue,green, all those. The wire you want goes to the lone black wire on the distributer it is on the far right side of your distributer. I'll post a pic in a few minutes. But that's what you want no coils no nothing just that wire.
the black wire is your tach signal.... because it's your coil fire event signal...


to understand how a tach works and to wire it correctly you should know that the ignitor gets info from the ecu when to spark, and the ignitor sends the signal to the coil.... the coil has a constant power source and fires when it receives a signal (or signal loss, depends on the system).... the tach is merely converting that signal wire to a readable number of sparks per minute divided by the number of cylinders you have.
 

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AE92DX 4AFTE
ae92
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1,749 Posts
i wired a sunpro tach with the green on the (-)diag. terminal with no problems... maybe your tach is set to 6-8 cylinders...
 

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G Man
1990 DX
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err, the black wire is round i thought...green or yellow is usually the signal wire, white is usually lighting, and red is usually 12V constant.

i had this problem with the buick, which had 6 coils. It was hard as :X to find the right coil to stick it under...when I found it, i took off the coil and stuck the wire in the slit where the metal conductor pin goes, so that when the coil was replaced, it held the wire in place...thats how many of my connections are done. probably not the safest route, but is def the easiest and quickest way. i havent had any problems with shorting or blowing fuses or anything yet. shit, half my stereo is jerry rigged like that (im in the process of redoing everything.)
 

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AE92DX 4AFTE
ae92
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1,749 Posts
yea it had a switch
 
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