Using gm iat with spoolinup harness, I've came across mut11 in the SD pnp harness thread but no eval for evoscan.

 

Should be the same as the eval for AIT. id have to double check my laptop, but Im pretty sure I just renamed my "Fuel Temp" request (mut09??) and all is well. There should already be a request for AIT and Fuel Temp, they should both have the same formula as default, just different requestIDs. That is the same formula you use for the IAT you installed, request ID depends on which method (fuel temp or AIT) you hooked it up.

 

Roger that ill give it another shot... Evoscan 2.7.,numbers didn't look logical when I logged last. but will def take another look..

 

I logged mut11, I get 27 or 26 if I log x. Or 1.8x-40 is 8.6 or 6.8

 

Mut3a has x*1.8+32 and is called air temp... I should try that

 

Mut3a.appears to be it. Is there a problem with my Rom if I'm using a pnp harness and its reading at that location? Is my Rom even using the gmiat @ 3a?

 

Just stick with MUT11, it is the one to use for logging. Eval is the same as with std sensor but what rom you are using, one of prepatched sd roms? There is IAT scaling that needs to match your sensor and prepatched roms should be ok to use with GM sensor.

Is your MUT11 reading matching your local ambient temperature? It should.

 

I'm using gm sensor on the prepatched 3d SD Rom. 3a matched my ambient temp. 44*. 11 gave 27 @ =x and 1.8*x -40.have me 6.8 and 8.6.

 

Ok, x-40 (MUT 11) should give correct temperature in Celcius degrees and prepatched scaling has worked for us with gm sensor. In IAT scaling there is defined voltage in analog input which corresponds to certain temperature (in celcius degrees as default, check your scaling). Maybe you can measure your voltage at that ecu pin and see if it matches to your IAT scaling.

 

It might not hurt to take a peek at the scaling in the 2d SD roms and double check that the 3D rom matches. I think I remember seeing some differences when I 1st went to SD with the 3D rom... But I was also using the fuel temp sensor to fake iat then, so the numbers never matched ambient temp anyways. Im on 2D now with a GM IAT and no scaling issues.

 

I cant check this right now but I remember that MUT 07 used for coolant temp was directly analog to digital conversion result and if that is logged, it will not match real temp if sensor is not OEM. Or actually 07 is not directly that conversion result, there has to be some math inside Evoscan for Coolant Temp (07) as eval is simply x but RAM address in 07 is analog to digital conversion.

If (and I believe so) this is the case also with MUT 3A, it is not correct one to monitor especially if sensor is changed to some other than OEM as math does not match anymore at least in all areas. If MUT 3A is almost correct, it gives us an idea that scaling table is not correct (if 3A really is conversion result = voltage is correct for that ambient temperature with OEM sensor, GM is quite near that in certain temps).

MUT 11 is the temperature used for fuel control etc etc so I would find out reason why it is not matching to your ambient. If you can post your rom we can take a look and compare to good known scaling which has worked for us with GM sensor.

 

here she is.

 

Try this, scaling was off in my opinion.

 

Ok, going to try that in a few. I see there is x-40 for metric eval in my evoscan, and the formula for degree F is x*1.8-40. That is what I am using. will report back with results in a few..

 

Well I've consistently logged iat and with 29* ambience I get 60 + while making a pull. I'll check for ambient temp coincidence in the am .