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Old 11-13-09, 03:54 PM   #350 (permalink)
RavenTai
Wrench Bender


 
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Join Date: Nov 2003
Location: Miami FL
Posts: 5,722
I should post this here also

Quote:
RavenTai,

I have an 86 4Runner with a 2LII-T swapped in. These engines are notorious for cracking heads, due largely to a slightly underpowered cooling system, and the known dead zone in the temp gauge. My 4Runner was originally a gasser, and has the original gauge cluster. Hopefully in tomorrow or in the not too distant future I'll pull my gauge out and see if it looks like yours - I know it's similar, but might not be identical. If it's not, are you able to give me the rundown on how to determine which resistors need to be added in? It would definitely be great to get that gauge working properly, Thanks

Thespruce

The first step is to see if the circuit is the same as the 80's gauge, see post #58 for a schematic,

http://forum.ih8mud.com/80-series-te...emp-gauge.html

Read that thread for the blow by blow on how we came up with the mod. long read but worth the time if you want to recreate it,

The circuit in an 80 gauge is a modified Wheatstone bridge, they used windings of the motors (inductors) in place of some of the resistors, changing the value of R1 moves the null temperature (center point of the needle) changing the value of R2 (replaces the zener) affects the range,

You will need to trace out the circuit in your 4-runners gauge to see if it matches the 80 series circuit.


Note, I would not use a R1 resistor of lower resistance than stock, circuit current is surprisingly high for PCB mounted components, dash melt down or fire could be the result if either the resistors wattage or resistance is too low.

are you using the 4 runner sender or the one from the new motor? it may not work with the later.

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