I have been told that the EJ temp sensor will not work with the EA dash due to different calibration on the gauges.granted you can put the EJ temp sensor in but it causes the EA temp gauge to read low.What if you were to put a resister in line with the EJ temp sensor-EA gauge wire to correct that issue?The wire that goes to the ECU would still be the same...Is this a better way to do it or is it messed up?

 

Or if I am opposite how could one increase the current enough to make the gauge read normal?

I don't know about the subaru temp senders, but USUALLY, resistance decreases as temperature increases, so adding a resistor would be going the wrong way.

 

I would just play around with an infrared thermometer and compare the temp readings to what the gauge says, in order to "translate" the readings of the gauge.

Correct, adding a resistor would decrease the readings.

 

So you need some way to decrease resistance. Perhaps, an anti-resistor

 

In all seriousness, the best way I could think of doing it, is plumbing the EA temp sensor into a heater hose some how. If you have access to parts from an EA81T water cooling kit, they relocate the water temp sensor to the heater hose. Could use the piece it has.

I wouldn't even consider putting the temp sensor in a heater hose. if you don't have coolant, your gauge is wrong. i.e. at the MNSubaru ice races, my lower radiator hose slipped off (appears that I just didn't get the clamp tight enough) and I lost all the coolant. I noticed the temp sensor creeping up to what would be normal temp, and knew that was too high. I get out and look, and sure enough, the radiator is cold and empty. put that hose on, tightened the clamp, and poured some more coolant in, and it's been running nice and cool ever since.

 

I've seen a number of aftermarket gauges that have universal, metric mounting adapters. so I think I'm going to go that way.

 

 

but here's my gauge at normal operating temperature (my radiator fan is on):

and yes, I know my oil pressure gauge isn't working. I indent to try to fix that this summer aswell.

I wouldn't even consider putting the temp sensor in a heater hose. if you don't have coolant, your gauge is wrong.

I'm going to fix that. Since I don't use the stock thermoswitch for the fans, I'm going to put a water sensor in there and wire it up to an LED. When the water drops below the sensor, a bright red LED is going to come on to tell me. Hard part is going to be finding a switch.

 

Btw, I don't see how having a thermosensor in the heater hoses, or a sensor in the thermostat housing makes a difference if you're losing coolant.

Btw, I don't see how having a thermosensor in the heater hoses, or a sensor in the thermostat housing makes a difference if you're losing coolant.

 

it does. if the engine get's warm, so does the thermostat housing...but as soon as you put rubber between the engine and the sensor, you'll lose that ability.

well I found out values for the ej and ea gauges

 

at 122*F there is 187.6 ohms

at 248*F there is 19 ohms

on the EJ gauge

 

on the EA gauge it reads as follows

158*F is 72 ohms

at 248*F there is 16.1 ohms

 

 

so I need a anti-resistor that has alot of anti resistance when cold and very little anti resistance when hot...

 

I think I will wire in a temp gauge that's sender screws into the same spot on EJ so I know if Im overheating.With my luck a hose would fall off and I would lose the motor if I had a sensor on the upper hose...

 

 

Anyone know the threads on the EJ temp sender?and for that matter the Ej oil pressure sender?

Hard part is going to be finding a switch.

 

 

Any heavy-duty truck/bus parts place should have low-water indicator senders. I've been meaning to put one on my car for a while, but haven't gotten around to it.

EASY. To lower a resistance all you have to do is wire in a second resistor in PARALLEL (mean that the second resistor has leads going to temp gauge wire and ground). This will drop the overall resistance in as seen by the guage.

 

formula for calculating it is here:

http://www.1728.com/resistrs.htm

 

I am too lazy to calculate right now, maybe in a bit if you ask nicely

at 122*F there is 187.6 ohms

at 248*F there is 19 ohms

on the EJ gauge

 

on the EA gauge it reads as follows

158*F is 72 ohms

at 248*F there is 16.1 ohms

 

 

so I need a anti-resistor that has alot of anti resistance when cold and very little anti resistance when hot...

EASY. To lower a resistance all you have to do is wire in a second resistor in PARALLEL (mean that the second resistor has leads going to temp gauge wire and ground). This will drop the overall resistance in as seen by the guage.

 

formula for calculating it is here:

http://www.1728.com/resistrs.htm

 

I am too lazy to calculate right now, maybe in a bit if you ask nicely

Since the EJ ECU reads off of the Temp sensor too, wouldn't this change the values the ECU sees as well, causing problems between closed/open loop operations?

Since the EJ ECU reads off of the Temp sensor too, wouldn't this change the values the ECU sees as well, causing problems between closed/open loop operations?

 

you could wire it in after the ECU. since you've already got the harness out, it wouldn't be too hard....I might try this next summer when I have things apart again.

doesnt the ecu read of the temp sender not the gauge?I know theres values for resistance for the ecu temp switch...

EASY. To lower a resistance all you have to do is wire in a second resistor in PARALLEL (mean that the second resistor has leads going to temp gauge wire and ground). This will drop the overall resistance in as seen by the guage.

 

formula for calculating it is here:

http://www.1728.com/resistrs.htm

 

I am too lazy to calculate right now, maybe in a bit if you ask nicely

 

 

Please please.with sugar on top.

doesnt the ecu read of the temp sender not the gauge?I know theres values for resistance for the ecu temp switch...

 

There is a completely separate temperature sensor for the ECM.

so then the sender for gauge could read "messed up" for all the ecm cares?

I put an ea temp sensor in where the old thermoswitch sat on the radiator. Not perfect, and it was only ever going to be temporary. At some stage I want to get an aftermarket temp guage that will work with the EJ at then run that off the sensor in the engine.

That would allow the gauge to read correctly at normal operating temperature, but it would mess up the scale, rendering it useless. The gauge wouldn't read all the way cold when the engine was cold, or all the way hot when overheating.

 

EASY. To lower a resistance all you have to do is wire in a second resistor in PARALLEL (mean that the second resistor has leads going to temp gauge wire and ground). This will drop the overall resistance in as seen by the guage.

i made a adapter to mount the ea sender in the top hose,but ended up just using the ej one after the ea one would move up and quickly with the slightest increase in temp.

Couldn't one easily just tap out the hole where the EJ sensor goes to larger threads to accept the EA sensor? it is only a small difference, should be plenty of metal to tap. Probably would need to be done with the engine, or at least the manifold, removed from the car. Seems like the most logical solution to me

There you go with that "logic" again...

I don't know, it might work. Let us know how it goes!

Couldn't one easily just tap out the hole where the EJ sensor goes to larger threads to accept the EA sensor? it is only a small difference, should be plenty of metal to tap. Probably would need to be done with the engine, or at least the manifold, removed from the car. Seems like the most logical solution to me

 

yea, you probably could do that, but i didn't want to disassemble my motor. I knew it worked great, and didn't want to mess with it. and the gauge works fine, it just looks different.

Couldn't one easily just tap out the hole where the EJ sensor goes to larger threads to accept the EA sensor? it is only a small difference, should be plenty of metal to tap. Probably would need to be done with the engine, or at least the manifold, removed from the car. Seems like the most logical solution to me

 

Thats What i did and it works great ! the wiring even plugs in , you dont need the EJ sender because there is a seprate sender for the comp. also puting the the sender in the rad will give you improper engine temp because with the thermostat closed there is no flow and if it sticks you could have a cold rad and an overheated engine .

 

 

Uuuuuhhhh.......?

Thats What i did and it works great ! the wiring even plugs in , you dont need the EJ sender because there is a seprate sender for the comp. also puting the the sender in the rad will give you improper engine temp because with the thermostat closed there is no flow and if it sticks you could have a cold rad and an overheated engine .

 

Do you recall what tap you used?>??