Author Topic: Blue Temperature Sensor Testing  (Read 2029 times)

Offline DKnight

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Blue Temperature Sensor Testing
« on: January 11, 2009, 12:59:16 am »
Well as it was cold today i thought i would do some investigating.

Now firstly im no electrical genius, so please any mistakes i make pull me up on it! Its just my own findings.

As posted before me and spaniel both seem to be plagued with this weird start up issue, to explain when i come to fire my car up in a morning, for the first 30-60 seconds, it runs really ruff, very much like a misfire, and smells really strongly of fuel. There after it runs fine, no problems at all.

I am 99% sure the problem is the blue temp sender.

The sensor works off simple readings, for example, cold the sensor should read about 3 - 4 ohms, this tells the car that its cold so it over fuels, as soon as it gets running the heat rises, the readings drop, and the car stops over fueling...

So my thoughts before my investigation was that the sensor just has a bad starting reading.

So i got 5 sensors:

A. Old Used Sensor
B. Old Used Sensor
C. Old Used Sensor
D. New Sensor
A. New Sensor GSF

Here is a graph to show the readings



The starting reading was the sensors, all stored in the same temperature outside for 4 hours (cold).
Now straight away my guess, was correct, the variation in cold readings was, what i think quite major.

4.30 / 3.68 / 4.08 / 5.40 / 3.00

out of those readings, the 2nd reading would be more suited to fixing my problem, as it is the lowest.

the 2nd reading (time reading) is sat submerged in the water (500ml) in a pan, each time, it was new cold water, and cold pan.

again these readings were quite varied, especially between the old sensors.

there after, the graph shows the readings, each time on boil, at 8 is boiling point, and then the 4 readings after were cooling down in the water, just to make sure

Now the actual flow of each reading i thought was pritty similar, but what worried me was the reading of the GSF sensor, its starting temperature was low and it continued, all the rest seem to stop around 0.20 at boiling, but the gsf one, is so low, so im guessing it will cause really bad underfueling when running?


So thats pritty much it, basically blue temp sensors seem to vary alot in initial start up temperature, which would explain the dicky start up, ive had it with a few G40's

Thats about it really, im going to try sensor B on my car as i think that is more suited to the car, i will update how it goes :D


Offline hayesey

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Re: Blue Temperature Sensor Testing
« Reply #1 on: January 11, 2009, 12:17:32 pm »
you sure you don't mean kohms?   ???

Offline DKnight

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Re: Blue Temperature Sensor Testing
« Reply #2 on: January 11, 2009, 12:41:55 pm »
yeah probably do lol

Offline supercharged spaniel

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Re: Blue Temperature Sensor Testing
« Reply #3 on: January 11, 2009, 01:05:24 pm »
as i said on the phone i personally dont think the start up issue is the sensors themselves.. 3 of mine left at room temperature read around the same 3kohms. and the aftermarket one like yours was way different from the others....i think from somewhere along the line the ecu is getting an interuption in resistance...mainly because combined between us nearly 10 sensors cant all be fucked..its really confusing stuff to be honest but i think our next port of call is to try another loom and ecu..laying theecu over the engine plug it all in and try morning start up...

Offline giorgio

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Re: Blue Temperature Sensor Testing
« Reply #4 on: January 11, 2009, 01:05:51 pm »
I told this to spaniel but I am not sure if he tried it.

just get a variable resistor [of the same range] and then just tweak that until you can get your car running right. that will completely eliminate the BTS.

Also - the differences cant be that critical or we would all have the issue.

Offline DKnight

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Re: Blue Temperature Sensor Testing
« Reply #5 on: January 11, 2009, 01:41:48 pm »
yeah i see what you mean, but i have had 3 G40's with this similar issue!

i dont think its the fact they are all fucked, maybe they just vary that much, they cant fix, or keep the starting temperature right, it could be a few factors, im off to test my theory now with sensor B...

Offline DKnight

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Re: Blue Temperature Sensor Testing
« Reply #6 on: January 11, 2009, 02:34:53 pm »
well sensor B did it for about 5 seconds then ran fine

im adamant its that initial figure that causes the problem, would explain the 30 seconds minute of ruff start i get , when the sensor is trying to get the level down, i checked once the ruffness stopped and the reading was about 2.50-2.00

hmmm