[Skimmer]

While doing my first oil change today on the Insight I noticed what looks like a sensor attached just behind the lower grille. It is a thin cylinder with two wires coming out of it. Is this an air temperature sensor of some kind? And if so, has anybody figured out a way to tap into this to display on the dash? Would be kinda cool to have an outside temp. display in the car.

 

[Foxpaw]

It is an air temperature sensor. I believe it has something to do with auto stop.

 

[joecvt]

Foxpaw is correct...A few months ago I posted an automatic warm / cold
air intake that will take heated air from the CAT in the winter time and
forced outside air in the summer time. With temps in the 30s - 40s I am
still able to get 60 MPG in a CVT !!! ... For more info on the automatic
warm air intake click here. Anyway, since that was working as I wanted
my next step was to make autostop still happen when it is 30 - 40 F as
well so I moved the sensor to a warmer part of the car. I made a small
bracket (from aluminum) and mounted just below the radiator hose on
the engine side near the MAP sensor. I was able to use the same wire
without cutting or extending it to reach a warmer part of the engine. So
now my car will autostop more often in the winter. I'm pretty sure when
it gets to 0F or below it will not autostop but I can live with that. That
sensor may also determine if the IMA motor starts the car or the starter
motor starts the car, so that part should still work the correct way because
if the engine is warmed up then the batteries are also warmed enough.

So far I have owned this car since March 2004 and now with temps in the
low 30s F I may still not heard the normal starter motor engage. Hopefully
it works when I need it to a few weeks from now.

JoeCVT - Just your average CVT owner

 

[Insightful Trekker]

Attempting to override the thermal management of the IMA battery pack will likely have disastrous results.

The high current flow required for IMA start *WILL* cause damage to the IMA battery pack if its too cold.

While I am not sure of the specifics, I believe that the thermosensors internal to the IMA case will limit IMA start regardless of the external thermosensors readings.

Its a high risk ($$$$) mod and for what benefit?

 

[Insightful Trekker]

The outside air sensor signal is sent to the Climate control unit only p.g. 65-3 of the factory ETM. The climate control unit then "interacts" with the ECM's ENGRDY signal p.g. 11-17 of the factory service manual.

ENGRDY = 12v no auto stop.
less than 1.0v with auto stop.


The climate control can override the auto stop function based on normal or econ A/C operation. And apparently several of its inputs are made to fail safe in preventing the additional feature of auto stop.

So far it appears that any failure or erroneous signal by the outside air temperature sensor can only prevent auto stop or bias the climate control units temperature control feature.

 

[Guest]

Hi JoeCVT:

___I cannot provide any more information then what Insightful Trekker has provided but in my own experience, the only time I had a non-IMA start was one morning when it was ~ 3 below 0 (Fahrenheit). You get those type of temps up there in NH, right? Moving that temp sensor around wouldn’t effect the start logic given wherever the sensor is relocated to, it would still be ambient in that new location. That is unless you have an engine block heater at work possibly? Autostop is great in an all-city/traffic jam but if worse comes to worse and you are sitting in a parking lot w/ no-autostop, turn the key. The downside of Autostop in colder temps is that when its cold, autostop drops the coolant temp fast and you might actually lose fuel economy while our little ICE’s are warming up back to a nice 175 - 190 +.

___I would spend your time on warm air mods and leave the temperature sensor alone given what has been posted about its actual purpose …

___Good Luck

___Wayne R. Gerdes
___Hunt Club Farms Landscaping Ltd.
___[email:2vj5r2wc][email protected][/email:2vj5r2wc]

 

[Foxpaw]

I think that the cold-start thing is based not on any external temperature sensor, but instead on the temperature sensor in the battery pack. I don't believe that the electric motor is particularly at risk in cold temperatures, it is the battery that does not like the cold.

 

[joecvt]

Thanks for the responses....From what I read from you guys and from
what I thought to begin with, I don't think thaty I am damaging anything
long-term by moving the sensor 1.5 ft back into the car....It does not
touch anything and I am not shorting or applying voltage to the wire.

Xcel: It usually does get below 0F for a week or two in NH...Last year
we broke a record low of -45F !!!! Thanks for letting me know when
your starter motor kicked in.

Thanks Insightful Trekker for the electrical explanation in your second post.

JoeCVT - Just your average CVT owner

 

[Rick]

Since we're on the topic of the temperature sensor a few weeks ago I poped my hoood and noticed the plastic clip that holds the temperature sensor to the front bumper had broken and my temperature sensor was just dangling there in front of the radiator. So speaking of which I really need to call and order a new clip.

 

[Skimmer]

So again, my question is, is there a way to tap into the data stream from this sensor to create a simple temperature display on the dash?

 

[Yves M.]

The service manual says that the sensor's resistance will grow with the cold temp.
About 11 K ohms at 14 F
6.3 K ohms at 32 F
4.0 K ohms at 50 F
2.5 K ohms at 68 F
1.6 K ohms at 86F
1.0 K ohms at 104 F

So if you can use the voltage between both terminals to provide some kind of interface, you are in business. Something that does not interfere with the car's "Climat Control"

 

[sharpmj]

The service manual says that the sensor's resistance will grow with the cold temp.
About 11 K ohms at 14 F
6.3 K ohms at 32 F
4.0 K ohms at 50 F
2.5 K ohms at 68 F
1.6 K ohms at 86F
1.0 K ohms at 104 F

So if you can use the voltage between both terminals to provide some kind of interface, you are in business. Something that does not interfere with the car's "Climat Control"

This is an old topic but since my Gen 1 Insight is missing the ambient air temperature in the grille I would think that if I put a 1.5 ohm resister in place of the sensor the car would think that it was always about 85F and therefore go into autostop even in cold temps. OK for me because I don't do that much stop and go in the winter.

2002 Insight Silverstone Metallic 32,000 miles

 

[crxbart]

So auto stop hasn't worked in my Insight since I got it except if the hvac system is turned off. From my what I've found on here it meant the ambient air temp sensor was probably cut or unplugged. It was both in my case. The sensor was still in the bumper, but no wires going to it. The plug was wedged in the bottom of the bumper cover. I grabbed the plug, and pulled it. It came right up, and exposed that the wires were cut. There was about 8" of length left, and it was sniped right off. Now, my problem is I can't find where the other end of the cut wires are so I can reconnect it? I'll looked all over, and I cannot locate any loose ends? Can you guys point me in the right direction so I can get this back together? I want to build a warm air intake tomorrow, as well as get this fixed. Thanks in advance.

 

[AbCaRed00]

Here's: electrical locations hopefully to find the loose end. A figure is therein. Hopefully you can solder the connections back.

 

[met-head]

A scangauge II will tap into this info as well as a plethura of additional readings. I always monitor the intake air temp, the coolant temp, gallons per hour, and load

 

[crxbart]

Okay, thanks for that info. So it looks like the wiring originates from somewhere on the driver's side under the headlight. I'll look there. I'm hoping I don't have to remove the front bumper to find it. I have a feeling I might though. I couldn't find any trace of it in there last night.

 

[sharpmj]

So auto stop hasn't worked in my Insight since I got it except if the hvac system is turned off. From my what I've found on here it meant the ambient air temp sensor was probably cut or unplugged. It was both in my case. The sensor was still in the bumper, but no wires going to it. The plug was wedged in the bottom of the bumper cover. I grabbed the plug, and pulled it. It came right up, and exposed that the wires were cut. There was about 8" of length left, and it was sniped right off. Now, my problem is I can't find where the other end of the cut wires are so I can reconnect it? I'll looked all over, and I cannot locate any loose ends? Can you guys point me in the right direction so I can get this back together? I want to build a warm air intake tomorrow, as well as get this fixed. Thanks in advance.

Since my Insight has never had the ambient air temp sensor, does autostop work with the hvac system turned on when you have one? Depending on the air temp.

 

[crxbart]

Since my Insight has never had the ambient air temp sensor, does autostop work with the hvac system turned on when you have one? Depending on the air temp.

It is supposed to work in ECON mode. Thanks to the help from the members of this board, I was able to locate, and solder the wires back to the sensor. I also relocated the sensor behind the radiator so it should read higher temps and auto stop should work more in the cold. Apparently the sensor is designed to disable auto stop in temps below freezing. I am about to go take it for a test drive. I also rerouted the air intake so it will suck off of the cat converter while I was at it.

 

[crxbart]

It worked. I had auto stop function as I rolled to a stop light with the ECON mode activated. I'm pretty happy about that. The problem, it only happened once, so I am guessing it still isn't an optimal location for the sensor. It was 24deg today as I was testing it, so it is cool it did work once. I'm just either going to have to change the location to an even hotter location, or remove the sensor, and solder a resistor in it's place.

 

[olrowdy01]

So again, my question is, is there a way to tap into the data stream from this sensor to create a simple temperature display on the dash?

Short answer ......... No (unless you can do electrical circuit design).

There is no data stream from the sensor. It is a thermistor that changes resistance with the temperature it senses.