Resistor for EGR temp sensor?

[Toahk]

Well ive been reading up on the whole EGR thing, and I read you can put a 100k ohm resistor in line to the EGR temp sensor or something to not throw a code. Can anyone elaborate on this? I have a few 100k ohm resistors just need to know what to do with them, thanks.

[IanS]

Im actualy wondering where this so called EGR temp sensor is cause I cant find it and I didnt remove anything electrical with the EGR.

[slide240slide]

I don't know about OBD 1 but OBD 2 senses if the pressure matches the specified pressure of the ECM maps and if it doesnt it will throw the check engine light on. Im not sure there is much you can do about it unless you have a Stand alone Engine management system that does away with the EGR system all together.

[Toahk]

Well the egr temp sensor is the little probe on the EGR, my car is boosting now and egr is all gone, and Im not throwing any codes...cross finger

[slide240slide]

I wouldnt worry about it, since the system is gone then it simply won't recirculate the exhaust gasses.

[IanS]

well Im planning a motor swap come spring and I just want this motor to last till then, but Im tired of seeing my cel, so far ive moved my secondary o2 sensor downstream of my high flow cat, and I also replaced my knock sensor but it still throws the code so I put a resistor in it, the only code its still throwing is the egr code. Does anyone know how to reset the obd 2 ECU Ive found plenty of stuff about the obd 1 system but not much on the obd 2, any insight would be helpful.

[ILikeMy240sx]

I have a OBDII and i just take the ECU out and turn the knob behind the ECU to reset it.

There is a guide in 240sx.org FAQ section and that;s how I reset it.

[:: orion ::]

Put a 100K ohm, 1/4 watt resistor in place of the EGR temp sesnor, and no more code.

To reset the ECU, use the instruction at 240SX.org, or my website (see my sig, below).

- Brian

[:: orion ::]

Does anyone know how to reset the obd 2 ECU Ive found plenty of stuff about the obd 1 system but not much on the obd 2, any insight would be helpful.

FYI, OBD-I or OBD-II doesn't mean JACK-**** on an S14...

There is very little difference between '95 and '96 S14s...it's really a non-issue.

Guys toss around "OBD-I" and "OBD-II" this and that...it really makes NO difference for anything on our cars...really.

- Brian

[sxconversion]

sorry to b

FYI, OBD-I or OBD-II doesn't mean JACK-**** on an S14...

There is very little difference between '95 and '96 S14s...it's really a non-issue.

Guys toss around "OBD-I" and "OBD-II" this and that...it really makes NO difference for anything on our cars...really.

- Brian

sorry for bring back this, but has anoyone done this, and if so where the hell do u put this resistor at?? i know where the egr temp sensor is on my car, do u just put it between both wires and call it good? and will this work on a 90 240?? pm me or reply

[Chezedik]

I have no idea what the temp sensor is, you may mean the bpt. Anyway, you fold the edges over to make leaves and then you shove them into the connectors to the solenoids. That will tell the computer (at least on an S13) that the solenoids are operating properly. May be different on OBD2.

[sxconversion]

I have no idea what the temp sensor is, you may mean the bpt. Anyway, you fold the edges over to make leaves and then you shove them into the connectors to the solenoids. That will tell the computer (at least on an S13) that the solenoids are operating properly. May be different on OBD2.

the temp sensor is the 2 wires that go right in front of the egr, they are not connected to the egr itself, i just wana know if this will work on a s13, once i get smogged i wana remove the egr because i know it is faulty.

[Chezedik]

Huh. Is this an SOHC thing, because mine did not have that. I can't comment on that resistor then. The one I was talking about was to the control solenoids for EGR and SCV. It says in the FSM that they will be considered as testing fine if they have a resistance of about 100 ohms, which is where I got that number from. Then again, I still have not ran my setup that way, so what do I know?

[sxconversion]

Huh. Is this an SOHC thing, because mine did not have that. I can't comment on that resistor then. The one I was talking about was to the control solenoids for EGR and SCV. It says in the FSM that they will be considered as testing fine if they have a resistance of about 100 ohms, which is where I got that number from. Then again, I still have not ran my setup that way, so what do I know?

well i unplugged my egr solonoid today, and it stayed out for like 2 hours, then came back on, does anyone know if the 100k resitor works or not??

[:: orion ::]

Been working on my car for ~4-5 years now...no EGR CEL since.

I removed all the hardware, left the BPT solenoid plugged in (but no vac lines running to it), and put the resitor in place of the temp sensor.

You can't trick the ECU into not seeing the solenoid, so don't cut those wires.

- Brian

[savatoge]

You can't trick the ECU into not seeing the solenoid, so don't cut those wires.

I did. Replaced my EGR/CCV solenoid with two 1K Ohm 0.25 watt resistors wired in parallel. One 500 Ohm 0.50 watt resistor would most likely work as well. No CELs.

[dawalude]

Been working on my car for ~4-5 years now...no EGR CEL since.

I removed all the hardware, left the BPT solenoid plugged in (but no vac lines running to it), and put the resitor in place of the temp sensor.

You can't trick the ECU into not seeing the solenoid, so don't cut those wires.

- Brian

Can you show a pic or a simple walk thru of how to replace the sensor with a resister from radio shack? Is it easy to do?

[:: orion ::]

Yes...find the sensor (2 wires, right in between the intake runners - #3 and 4, IIRC).

Cut the 2 wires, and reconnect them using the resitor as a "splice".

Done.

- Brian

[dawalude]

Ok, so each wire would require a seperate resistor to reconnect them?

[savatoge]

No...connect one wire to one lead on the resistor and then connect the other wire to the lead on the other end of the resistor.

The EGR temp sensor works by varying the voltage that the ECU "sees" depending on the temperature in the EGR. By placing a resistor inline, in effect taking the place of the EGR temp sensor, the resistor will provide a constant voltage, which the ECU will see as constant temperature.

[dawalude]

Ok, thanks! Is this the EGR temperature sensor? It was the only plug I found that had 2 wires going into the plug, and was not above an injector or out of sight. Is it the red one? The one right behind the throttle body? The blue one only has 1 wire going into it. BTW, this is a stock 90 240sx. Thanks!

[:: orion ::]

The EGR temp sensor works by varying the voltage that the ECU "sees" depending on the temperature in the EGR. By placing a resistor inline, in effect taking the place of the EGR temp sensor, the resistor will provide a constant voltage, which the ECU will see as constant temperature.

Correct, except the ECU looks for a resistance within a certain range.

The EGR temps sensor is just a variable resistor...more heat = more resistance.

All the ECU does is check OCCASIONALLY...not all the time...that the EGR temp sensor is reading within a certain range of resistance...this tell the ECU that it's hotter in the intake manifold than normal, so the EGR must be sending exhaust gas through as it should.

If you have a resistor inline that ALWAYS gives a proper resistance...then whenver the ECU "looks" or checks...it always gets the value it wants.

...

And in that pic...it's more likely the BLUE plug...that's the correct style plug, and it should lead to between 2 runners...the sensor just has 2 _small_ black wires coming off of it.

- Brian

[savatoge]

Correct, except the ECU looks for a resistance within a certain range.

The EGR temps sensor is just a variable resistor...more heat = more resistance.

Yeah, thanks for the correction...I meant the ECU looks at resistance as it varies and by using a resistor we are keeping the resistance at a set value that we want the ECU to see. But I thought it was inversely variable...more heat in the EGR results in a lower resistance. Can't remember without looking at the FSM...

And in that pic...it's more likely the BLUE plug...that's the correct style plug, and it should lead to between 2 runners...the sensor just has 2 _small_ black wires coming off of it.

Again without the FSM or popping my hood, I can't recall definitely, but I think the EGR temp sensor is located in between runners two and three.

[dawalude]

Thanks guys I found it between the intake runners...no CEL all day, thanks guys hope it continues!

[RatedR]

Is this what the EGT sensor looks like?

This is where this is found....between runners 2 and 3This is the connection to the sensor...This is the sensor itself.....

if this is not the EGT, what sensor is this? Its the only 2 wire sensor I see on the intake manifold.....

[Ligouri Rd]

Yep that is it. Didja have fun finding it, I know i did...way the frell down inside the intake manifold? Its a frell of a lot easier off the car, but not everyone has that option.

[RatedR]

Actually I found it pretty easily, thanks for replying by the way.I found out my wife's s13 has an intake mani leak between the top and bottom halves so I figured I would put the resistor in when I re-do the intake mani gasket.....

[KA-T]

Okay...okay.....sorry if i'm bringing this thread back up...but i feel this is important.... I'm about to put the resistor in line with the EGR temp sensor... But now i've heard 3 differetn valued resistors..

100k resistor .25 watt

1k resistor .25 watt

500 resistor .50 watt

So which one is it??? Who has used what and is still working?

[deviousKA]

The ecu does not read the EGR thermistor resistance per say, the egr circuit uses a standard A/D (analog voltage to digital conversion) with a conditioned "dual purpose" voltage feed.

The thermistor when changing resistance to ground increases or decreases the conditioned voltage and this is picked up by the A/D.

Only the california model S13 ecus should be throwing EGR codes with an incorrect voltage. There are workarounds, but the later models used more complex algorithm and actually supported true diagnosis of the EGR, and for these the best way to go is simply flashing some non-cali code.

You can use the converted EGR temp circuit for map sensor, wbo2, or conditioned thermocouple input on the ka24e

[deviousKA]

Im not exactly sure of what resistance is needed to trick the circuit, but there is an easy way to find out.

Get the car to full operating temp with the EGR hooked up and make sure no codes are thrown. While still at full temperature, unplug the EGR temp connection and simply measure the resistance.

1/4 watt resistor is fine.

The problem most are probably having is matching the resistance of the sensor when cold. The ecu begins reading the voltage only after a certain coolant temperature, so with this configuration it would be sensing as cold when it should be at full temp, throwing a CEL.