Well a little back story. I recently just returned my GSR to stock with a fresh GSR motor from the machine shop....

After gettin all the wiring gremlins taken care of. i stupidly swapped the IAT and Purge plugs and was gettin a CEL code 10. after driving a couple days like that i swapped them back and the CEL went away and shortly afterward i was getting an intermittent CEL code 43 (fuel system supply) after researching a lot i went ahead and replaced the 02 sensor with a Bosch one from autozone and havent had the CEL on ever since (approximately 4 days of varied driving since).

Problem is now my Car is getting TERRIBLE gas mileage.. last tank i aveaged 20 mpg... and looking even worse this tank. went 115 miles and used half a tank of gas. I opened the ECU to inspect it and noticed that my Q31 resistor was burnt and after searching i have found this only controls the EVAP purge (which i have removed anyway).... as i was looking the ecu over i have found a White sticker and black looking burn streak across the Knock board of my OBD1 P72. I am not sure what this sticker is for an towards the end of the burn streak the board looks a little raised ....? i am receiving no CELs anymore and not sure what this is. Also i shot a pic of the cover of the ECU because im not quite sure what that plastic mini covering attatched to it is.....

Any insight on this stuff or any ideas what that burn mark could be caused from or what that sticker and that plastic stuff on the cover is for?

May be totally unrelated to my horrible fuel consumption issue but still would like to know. Thanks.

 

i dont know, but nice s2k

 

Could it possibly be ink from the stamped letters on the board inside the ecu? I could be wrong, but most resistors have the reference designator R.. in front of the number, are you sure the burnt part is a resistor since the designator on it starts with a Q (could possibly be a transistor or something)?

 

Q31 is for intake air temp, not purge... Your intake air temp sensor is probably now fried as well.

 

Check to see if the q31 Transistor's crack. if so then it not longer good. You said you drove the car with CEL, and that can dangerous. You could done damage to your car but lucky. Try open the back plate and see if any burn. I would get another ECU that well known. I would put back everything it was used to be under the bay.