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Pi Swap and double temp sensor issues ( Fix for if you do not have a tap 3/8npt tap )

Lordgufi

Well-Known Member
Basically this is just a quick write up with how i came to do this. I dont know if this is on the net some where else but this is what I did to over come this problem.

if your like me you have a plastic intake manifold from a 2000 or so PI motor. which has no place for a second water temp sensor. This leaves you with 1 of 3 options.

1 Ditch the plastic cross over manifold and buy a PI with alum and tap it.
2 tap the water neck
3 rewire the temp sensor.

and now you say... well how do you do that... rewire the temp sensor.

well its quite easy and if you currently thinking... gufi your a nutcase... your probably more than correct. HOWEVER this is what I did.

I took a multi meter and checked the sensors output voltage at approx the same temp and instantly noticed they both use the same voltage for their output at the same temp. So you say what does this mean to you?? it means you can take a spice of the red/white wire of the guage wire and splice it into the light green/red wire of the ecu temp sensor and they will both work directly from the same sensor!!

total work now that you dont have to do the research like i did..
3 min ( longer if you forgot a tool some where or have to goto the store )

i used two alligator clips and approx 8 inches of wire and some black tape to cover the sensor plug/alligator clips ( DO NOT PLUG THE SENSOR BACK IN, LEAVE THE ECU SENSOR REMOVED AFTER YOU HAVE INSTALLED THE LEADS TO EACH WIRE OR YOU WILL CAUSE A SHORT )

to verify that the setup worked i pluged in my SCT tuner and data logged the ECT temp. before the fix it read approx 90-110 ( engine bay temp, not very usefull if your fans dont turn on untill 170-180 ). after the fix i watched it rise from ambient temp to 202 Deg F and then return downward to 194 ( 180 deg thermostat )

:rock:

and :thefinger: the second sensor


EDIT: now that i have driven the car approx 50 miles i'll give a little feedback on this mod. There is a slight drawback. when the car starts from key off you will get a p0118 code ( engine coolant high temp ) this is becuase of how the guages power on and off while starting the car. there is a break in voltage momentarily and because of that the ecu sees no voltage ( causing an electrical "open" condition ) there fore the ecu sees the sensor as faulty. so every time you start your car you will need to clear the code, however upon further datalogging i noticed once the guage starts working the ecu will allow you to see normlal operating temps and after you clear the code it will not come back untill you turn the key to the off position ( remove key ) if you leave the key however in the 'on' position and restart the car the code will not return.

SO iether i need to see if i can have the code disabled or go ahead and order the correct tap and then then sensor can say :thefinger: to me
 

Lordgufi

Well-Known Member
it works. but its currently a bandaid. the first time it didn't toss the code because the key was on the entire time i did it energizing the guages. i wasn't able to watch the voltage because i was the only person there so watching the volt meter while start the car is impossible. aside from the CEL it works flawlessly. i will be buying the tap and doing it correctly soon. i just needed the fans to be able to run while driving the car for the time being and no one in town has a 3/8ts NPT tap that could get it here before monday ( tuning today and track on sunday )
 

yosemiddysam

Well-Known Member
Donator
I am telling you I have a complete set opf taps. Why dont you swing by the house and take a peek.........
 
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