A friend of mine says his 02 FLHT is having cold start issues. He ordered a new temp. sensor, hoping that this will fix the problem

Does anyone have a readers digest version of how the ECM does the enrichment for cold start?

what sensors does it look at in the starting process..I'm looking for the logic of how it works.

Lets assume the ECM powers up and sees proper voltage and fuel pressure, and as it cranks it detects oil pressure and that allows the ignition process to start.

How does it know how much fuel to add? there isn't a coolant sensor, so what does a an air cooled sysyem use? How does it differntiate between cold starts, and start from operating temp?

Does the tempreture affect the engine timing?

(sometimes I miss the choke lever)

 

during a cold start, no sensors are actually involved. It uses a canned map.
It does look at the TPS signal for closed. This tends to get a wear spot in it.
Have him try applying a small amount of throttle during cold start.
There is an air temp sensor in the intake. But this tells the ECM the intake is getting cold or warm air after warm up and to adjust accordingly.
I ride mine in 20 degree and colder weather and sometimes need to do this during first start.
However it does actuate a Iac motor. this assists the cold start and warmup
idle.
The mapping adjusts timing and amount of fuel.
I would suggest he buy the servie manual and the electronic diagnosis manual.
It will tell him how to test the sensors to see if they are within limits.
also check for any trouble codes.
Also check for quality of fuels and the filter.
This is just basic info not all inclusive of every year and model.