View Full Version : 1.6 dirt car tuning

06-28-2010, 05:40 PM
Ok we were able to get 4th in heat and 8th in feature out of 30 cars with our 1.6 90 st dirt car, after pulling motor and radiator out out of old car and putting in new car it started to run about 230 240 in feature and never ran hot in old car for 30 races. Motor not hurt but my ? Is I didn't have time to hook up O2 cause wire end were different and wanted to no if this could be the main cause of this or something else. I am hooking up O2 today but wanted to see what else to look for. Thanks for any and all help

P.S. 2.2 auto car getting cage now

celica race car
07-02-2010, 09:16 AM
I'm not sure if not having the O2 would cause it to run lean but if it's running lean you will have an increase in heat.

07-08-2010, 05:06 PM
Ok but how does the O2 communicate to ECM and how does that effect the fuel ratio to injectors

07-08-2010, 05:28 PM
O2 sensors generate a voltage that is sent to the ecu. The ecu reads the voltage and determines if the a/f mixture is rich or lean and adjusts fuel accordingly. When a signal is not detected the ecu will simply allow extra fuel to be sprayed into the motor as a failsafe. So if the O2 sensor is not plugged up then you will run rich. It shouldn't effect engine temps at all.

07-08-2010, 08:44 PM
So would it be better to leave O2 unhooked to increase a/f ratio or change the input voltage from O2 to ECU to increase ratio

07-11-2010, 04:07 PM
without the O2 sensor your motor is going to lose power not gain power. the motor's fuel system already runs rich with the O2 installed. without it the ecu will be extremely over fueling the motor. the idea is to lean out the a/f ratio to make power. running rich will not make power but will keep the motor from popping.