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After market Water Temp sensor

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Offline Shizamaaur

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After market Water Temp sensor
« on: May 06, 2008, 05:05:40 PM »
A friend gave me an oil pressure sensor water temp sensor and amp sensor. Im curious where to mount the water temp sensor since the actual assembly bolt is bigger than the stock one... any ideas???

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Offline aaron74

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Re: After market Water Temp sensor
« Reply #1 on: May 06, 2008, 10:22:52 PM »
You can drill and tap the lower thermostat housing, you can Tee with the sensor for the ECM, I used upsize pipe thread fittings for the hole left by my a/c switch (but I am not getting great response from the meter because I haven't vented the obvious air lock inside the fittings), or (best option, I think) you can buy a rad hose fitting (32mm IIRC) that is threaded for your sensor off ebay or at a rod shop - just cut rad hose, insert adapter and off to races. 
Someone on this site also used the coolant line to the idle air control valve:
http://www.zukiworld.com/forum/index.php?topic=13321.0

I now have to plumb in a second one for oil temp when I run the lines for the Frantz filter and thermostatically controlled oil cooler so consider yourself lucky.
Aaron
I used to be indecisive but now, I'm not so sure.

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Offline Rhinoman

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Re: After market Water Temp sensor
« Reply #2 on: May 07, 2008, 04:50:37 AM »
You can drill and tap the lower thermostat housing, you can Tee with the sensor for the ECM,

Don't do this. The impedance of the gauge will affect the voltage and throw out the ECU.
2000 Vitara 1.6, 3+3 Lift, 33"MTs, 5:83s, LWB brakes, Winch, Snorkel, Safari Rack
1986 SJ413K PickUp, 1.6L conversion.

OBD1 - Full diagnostics on a PC/Laptop: http://www.rhinopower.org

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Offline aaron74

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Re: After market Water Temp sensor
« Reply #3 on: May 07, 2008, 10:45:00 AM »
Hmm ... I would have thought they were both basically at ground here and wouldn't have worried about it.  Do you really think it is that sensitive?  I just envision the almighty ECU/ECM as a complex if/or/nor box with a nice little program map for the input from the sensors.  I may have to revise my global view of the kick 'brain.' 

I thought I was going to use the boss at the very bottom of the front of the thermostat housing until I pulled the thermostat apart and realized that it does not go into the coolant but runs under to the intake?  That actually ruined my plans for a nice clean install without a goofy adapter (like the one I have with the afore-mentioned airlock  :P.  I might drill and tap the hole that I have the adapter in now (I swapper the old gauge sensor to the a/c switch spot and have my goofy adapter sticking out the front.)
I used to be indecisive but now, I'm not so sure.

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Offline Rhinoman

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Re: After market Water Temp sensor
« Reply #4 on: May 08, 2008, 05:02:36 AM »
Hmm ... I would have thought they were both basically at ground here and wouldn't have worried about it.  Do you really think it is that sensitive?  I just envision the almighty ECU/ECM as a complex if/or/nor box with a nice little program map for the input from the sensors.  I may have to revise my global view of the kick 'brain.' 


The sensor is effectively a variable resistance. The ECU supplies 5V through a fixed resistance and measures the voltage change caused by the change in sensor resistance. The gauge will work in a similar manner but probably supplies 12V. Add the two signals together and then calculate the efffect of having the gauge in parallel. The input voltage to the ECU will be wrong and therefore so will the value returned from the Look Up Table (map).
I've done a fair bit of work with the Zuk ECU, if you're interested its published here:

http://www.btinternet.com/~j_holland
2000 Vitara 1.6, 3+3 Lift, 33"MTs, 5:83s, LWB brakes, Winch, Snorkel, Safari Rack
1986 SJ413K PickUp, 1.6L conversion.

OBD1 - Full diagnostics on a PC/Laptop: http://www.rhinopower.org

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Offline aaron74

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Re: After market Water Temp sensor
« Reply #5 on: May 08, 2008, 09:47:41 AM »
I'm not second-guessing you at all Rhinoman.  I just think of the entire block as ground and if you screw something metal into it, that is ground too - the entire electrical system on the automobile is common ground.  I just wouldn't have thought the gauges would have any measurable effect on each other because they have a common ground. 

Fortunately, I am not using a 12V gauge either - it's mechanical so it is not supplying a voltage that could interfere anyway. 
I used to be indecisive but now, I'm not so sure.

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Offline Rhinoman

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Re: After market Water Temp sensor
« Reply #6 on: May 08, 2008, 11:52:02 AM »
I'm not second-guessing you at all Rhinoman.

No offence taken, I'll leave it there because the explanation needs too much maths for this forum.
On another forum I saw someone use a hose from a FWD Ford Escort that had a built in boss for a fan switch. I have some gauges to fit to my SJ413 so I'm going to check this option out. Where is the A/C switch usually located?
2000 Vitara 1.6, 3+3 Lift, 33"MTs, 5:83s, LWB brakes, Winch, Snorkel, Safari Rack
1986 SJ413K PickUp, 1.6L conversion.

OBD1 - Full diagnostics on a PC/Laptop: http://www.rhinopower.org

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Offline aaron74

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Re: After market Water Temp sensor
« Reply #7 on: May 08, 2008, 12:13:26 PM »
The a/c switch was right above the ECM/ECU sensor on the thermostat housing.  It was too close for the temp sensor housing adapters so I switched the factory gauge sensor to this location and put the airlock special on the front :).  I should probably qualify this by saying that I have a 16V and it is likely different on an 8V. 
I used to be indecisive but now, I'm not so sure.