tricking the temp sensor? [Archive] - SaabCentral Forums

: tricking the temp sensor?


gpm2003
10th May 2003, 04:02 PM
this guy is selling something on ebay for 10$. it works to trick the temp sensor into thinking colder air is coming in(when its really not cold). he says this is 100% safe and will add almost 20 horse. anyone know anything about this?? thanks
graham

Jim
10th May 2003, 05:37 PM
Umm It sounds really odd! and something tells me you should stay away from it, of course I may be wrong lets see what the rest of the guys and ladies here say.

Gordy
11th May 2003, 06:19 AM
I'm sure I saw something on Saabscene for this, it wasn't well received.

Aah here it is...

http://www.saabscene.co.uk/ubb/ultimatebb.php?ubb=get_topic;f=23;t=000141#000000

Glib
11th May 2003, 10:59 AM
If this is a fix for cold driveableity problem where the ECU is the cause you can trick the brain that the engine is colder than it actualy is.
Cheeper than relaceing the ECU but not Emisions aproved.
I havent seen the kit you are talking about.
This is the scoop. On older 900 and 9000 sometimes the LH ECU's peramiters wold not be able to allow for a cold driveability conditions. (ie proper dwell for AIC motor,injector dureration, ect..). What you could do is install a resistor (1w,1000ohm) witch was cotrolled by an add thermo switch ( saab part 75 19 ...,can't remember at ths time)in series with the engine temp sensor blue wire.
On turbo 9000's an additional block was installed in one of the engine's heater hose (so you would have a place to mount to thermo switch)
When cold this alowed extra resistance for the engine temp sesor, so the ECU compensated , gave fast idle, good thing.
When the themo switch warmed up the resistor was bypassed and engine tmep monitoring was back being engine temp sensor alone .
This mod. can not hurt your car. But again I don't know what they are selling on Ebay
This dose work but will not fix any faulty parts such as (AIC valve ,bad temp sessor,missadjusteted specs,Old tune up parts, ect...)

exsaab tech
15th May 2003, 02:45 PM
this mod is acceptable but as mentioned fuel economy will go down considerably. all you are doing is telling the car it is cold outside,therefore you are effectively running the engine on constant choke. you will be lucky to get any better than 15mpg. furthermore this mod you mention can be picked up from any electrical supply store i.e radioshack for about 20 cents

Glib
16th May 2003, 11:36 AM
Sorry if any confusion. The mod I listed dose work but just for cold start and dose not effect drivability after the car raeches opperating temp. The mod for the air mass meter I would not recomend, exsaab tech is right.