Inlet Air Temp Sensors

[DonE]

For you guys who did an EFI conversion, which IAT did you use? I am using a Bosch wire sensor, but not convinced its the best choice for this application.

Thx

[Jeff Alton]

I use a standard GM style one on my 3.4 NA motor.

Cheers

[dean]

Hi Don,

I use a Bosch one also. I can look up the part # if you want. I think mine seems to work fine.

What is the problem with yours?

[David]

I use the Bosch wire sensor also. I haven't had any problems.

[DonE]

I use Bosch part 0 280 130 085, installed per Bosch's instructions. I'm not completely convinced it is as fast as it should be. Although the tech sheet shows its the fastest sensor Bosch makes, it seems to lag in varying conditions. It also seems to retain heat soak. The sensor is mounted about 6 - 8 inches before the throttle body, but after driving the car, then letting it sit for 3 - 4 hours, it will show a high temp regardless of ambient.

For example, I drove the car to work the other day, ambient about 15C which coincided with the sensor value. When I took it to lunch about 4 hours later, I felt the pipe around the sensor (cool to the touch), but the sensor showed ambient around 36C when it was about 20C. It took about 3 min for the sensor to come down to something close to ambient. While waiting for the temp to adjust the ECU thought it was hotter than it really was, and pulled fuel per the temp correction table - it ran lean until the sensor started showing ambient.

It also took about 3 or 4 min for the oil temp gauge to start registering temp, so I know the engine was cool when started.

[dean]

Originally Posted by DonE

The sensor is mounted about 6 - 8 inches before the throttle body, but after driving the car, then letting it sit for 3 - 4 hours, it will show a high temp regardless of ambient.

For example, I drove the car to work the other day, ambient about 15C which coincided with the sensor value. When I took it to lunch about 4 hours later, I felt the pipe around the sensor (cool to the touch), but the sensor showed ambient around 36C when it was about 20C. It took about 3 min for the sensor to come down to something close to ambient. While waiting for the temp to adjust the ECU thought it was hotter than it really was, and pulled fuel per the temp correction table - it ran lean until the sensor started showing ambient.

Mine is mounted in the same place. Mine does sorta the same thing but not for 4 hrs. Do you have a hand held temp gauge?

I have compensated for heatsoak with more fuel at those temps. Don't know if it is right but it seems to work.

[David]

Do you have the ECU set for the sensor? The factory IAT sensor setting on the Motec is not the quick response Bosch unit so I was getting weird temperatures until I set it to the right sensor type.

[DonE]

Dean - I can't adjust the temp correction because when the inlet air actually hits the higher temp, it'll be too rich. The engine coolant temp correction is already set perfectly, so I don't want to screw with that either.

David - LINK gives me two options for the sensor - a generic Bosch and custom, where you set the parameters. Tonight, I'm going to try to find the ohm value per given temp for my specific sensor. You might be right because there are two Bosch IAT sensors with slightly different curves.

Thanks for the suggestions.

[les_garten]

Originally Posted by DonE

Dean - I can't adjust the temp correction because when the inlet air actually hits the higher temp, it'll be too rich. The engine coolant temp correction is already set perfectly, so I don't want to screw with that either.

David - LINK gives me two options for the sensor - a generic Bosch and custom, where you set the parameters. Tonight, I'm going to try to find the ohm value per given temp for my specific sensor. You might be right because there are two Bosch IAT sensors with slightly different curves.

Thanks for the suggestions.

Hi Don,
I don't know what sensor I have. Touching the "outside" may not tell you much. I would get into the same situation and pull it out and check the temp with a IR temp gauge real quick. It may be dead accurate.

[hobieboy]

I use Bosch sensor as well with mine. No issues so far.

Les made a good suggestion, though after 4 hours (& that's for lunch ? ), any left in your intake track should have been cooled or the area around your intake pipe should be warm too?

[les_garten]

Originally Posted by hobieboy

I use Bosch sensor as well with mine. No issues so far.

Les made a good suggestion, though after 4 hours (& that's for lunch ? ), any left in your intake track should have been cooled or the area around your intake pipe should be warm too?

I think the first step would be to "CONFIRM" that your sensor is reading wrong.