EGR Temperature Sensor function, California car.

[moduleunknown]

Can anyone tell me the exact function(s) of the EGR temperature sensor on a California VR4?

I suspect it's only a functionality check, but have been unable to find any info.

The reason I ask - I've failed smog, but passed the sniffer test (with a bad EGR valve even)! The sensor in question has nothing to do with my failure, nor have I thrown a CEL. The only reason I ask is because I ordered a replacement EGR valve but received the wrong part (does not have a port for the sensor).

...and that's lead me here - wondering if I can just use this EGR valve anyway. I would imagine I could pull the sensor, wire a resistor in it's place and never see a CEL. I'm fine with that, but before I proceed I need to know if that sensor serves any other purpose than a functionality check.

Looking at the manual, I find the following:



I'd imagine the lower value/range tells the ECU we're in open loop, and the second, higher value/range reports closed loop. ...back to this resistor idea (if I did go that route), what range would I want the ECU to see for the rest of its life?

Or perhaps I just keep the car off the road and wait even longer for the right EGR valve. /ubbthreads/images/graemlins/banghead.gif

 

[ktmrider]

Ok cmon you do a search on this? Yes there is a "resistor mod", hint it's on the ECU, hint it's CA Emissions model specific....

 

[moduleunknown]

I've searched, and I'm well aware of the resistor mod. You're right, info on how others have done it is easily found. What's not easily found (at least in my searches) is information regarding the function of the sensor - what happens when it reports either state/range of resistance shown above, and what effects will result in the mod constantly reporting that's it's always in only one state/range.

I will not blindly follow information on the internet that only shows how to eliminate the sensor from the system without knowing exactly why/how it works and what areas of operation it could potentially affect (if any).

If your search abilities are superior to mine and you're able to easily pull up the information I'm looking for, would you mind taking a minute and sharing a link?

 

[AnotherNewb]

The EGR temp sensor prevents the EGR valve from opening at too low of a temperature, in California. Too low EGR temps will not air in reducing emissions, in California. In any other state it apparently has no effect.

If you want to leave the ECU alone and fool it you can take a 62Kohm, 1watt resistor and solder it between the two wires and wrap all of this up real snug with electrical tape. This will make the ECU see that the sensor is operating normally and you'll will never get a CEL light again with this small mod. But really the resister in the ECU would be simpler and more long term, after all, you're not modifying it, you're just returning it to the way the rest of the country recieved their cars.

 

[moduleunknown]

Thank you.

So here's my problem now. The EGR valve I received was Federal spec. Everyone I have contacted since has been unable to get ahold of a California spec EGR valve. They seem to be discontinued, everywhere.

Problem is that I need a working EGR valve on the car as it's functionality is tested during the CA smog test. It would seem that I now need to run the Federal EGR valve, but I can't ditch the CA system that relies on the EGR temp sensor and switch to the Federal system with the thermo valve; because then I've modified my emissions system and will again fail.

If I did this resistor mod and still ran an EGR valve (the Federal version), then would it be opening at too low of a temperature, and if so, how would that effect driveability/operation of the car until it has warmed up? I don't want to do anything that may have a negative or damaging effect.

At this point I'm really just looking for a temporary solution that will get me past smog, then I'm blocking off the valve and won't think about it again until next time.

 

[moduleunknown]

Got this all sorted out.

My inital question(s) may have seemed a little retarded, but that's just me trying to figure out my options and exactly how things work as I'd rather not mess with anything without a full undertsanding. I left out the fact that I have ecmlink for this reason.

Through this forum and the ecmlink forum I've learned that ecmlink is based of '92 federal code, so the fact that an EGR temp sensor even exists in my car is moot. It failed to be acknowledged as soon as I installed ecmlink. I should have configured ecmlink's egr output to operate in normal factory fashion since day 1. Unfortunately, I failed to realize that (until now).

That said, ecmlink will operate the system normally in absence of the EGR temp sensor. Running a federal EGR valve on a CA car is no problem. All is well and working normally again (now).

It would seem that if anyone with a CA car ever needs to replace their EGR valve to pass smog, they'll probably only ever be able to get a federal EGR valve as everwhere I went told me the CA EGR valve is no longer available. Should you want to run a federal EGR valve on a CA car with no visual modifications to the CA emissions systems, you'll need ecmlink to operate it correctly.

 

[ktmrider]

My bad too, didn't read carefully enough plus forgot about AR Cali stuff. Learned a few new things also.

One question, did it ever get to the point where the smog inspector/ref checked for the temp probe? The ECU configuration resistors, R129/130 can't remember which one does emission type, seem to change the timing of EGR use and not the functionality of the EGR itself. Even knowing where the temp probe isn't much help getting to it LOL. Figured the smog tech would be looking for an EGR only.

 

[Fiascoxl]

Little off topic, but if any of you guys ever need any Cali smog stuff let me know. #740 is a california emissions car, and I have taken it all the smog equipment off.

 

[moduleunknown]

Quoting ktmrider:
My bad too, didn't read carefully enough plus forgot about AR Cali stuff. Learned a few new things also.

One question, did it ever get to the point where the smog inspector/ref checked for the temp probe? The ECU configuration resistors, R129/130 can't remember which one does emission type, seem to change the timing of EGR use and not the functionality of the EGR itself. Even knowing where the temp probe isn't much help getting to it LOL. Figured the smog tech would be looking for an EGR only.



The temp probe was never checked. The question about it's operation only came in to play when I received a federal EGR valve from mitsu which didn't have the port for it - and that was just me trying to figure out what to do next.

p.s. I'm replying to this after having just returned home from passing smog! I'm free for two more years. /ubbthreads/images/graemlins/smile.gif