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2016 FLSTC--Exhaust/cat question

Started by Ratfade, February 14, 2020, 09:18:56 AM

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Ratfade

I'm looking at a really nice 2016 FLSTC at a local dealer. The bike appears to be basically stock but with Vance and Hines slip-on's.
Looking at the exploded parts diagram for this model's exhaust, I see the front and rear oxygen sensors but no mention of the catalytic converter. Where is it?
Thanks.

Princess Butt

On my 2015 FLSTC, cats were in the mufflers.
Shiny side up, rubber side down.

rigidthumper

In someones scrap pile, if you have aftermarket mufflers :)
Ignorance is bliss, and accuracy expensive. How much of either can you afford?

Ratfade

Thanks; I know in cars there are usually pre and post cat sensors. Obviously not the case here. Does this mean this system is a basic closed loop system that allows the ECM to make some compensations?

rigidthumper

Yes, within the EPA restrictions, and design of the stock system.  If added components take it outside that range, it cannot completely compensate.
Ignorance is bliss, and accuracy expensive. How much of either can you afford?

Pirsch Fire Wagon

Quote from: Ratfade on February 14, 2020, 10:06:03 AM
Thanks; I know in cars there are usually pre and post cat sensors. Obviously not the case here. Does this mean this system is a basic closed loop system that allows the ECM to make some compensations?

They're closed loop systems regardless if there are Oxygen Sensors Present.

The purpose of the down stream (after the CAT) is to compare with the Up-Stream to ensure the CAT is working correctly by adding or removing fuel. More efficient. When tuning is done the changed cells are modified as Open Loop Cell Values for those specific cells (basically uses those set values in lieu of the stock values in the cells.

If converter efficiency had declined to the point where the vehicle may be exceeding the pollution limit, the ECM will turn on the MIL and set a diagnostic trouble code. There are only two places in the Service Manual where an Oxygen Sensor is replaced. So, they're pretty durable items.

Harley-Davidson uses a single 02 Sensor in all their models.

The older a two wire (non heated) and the newer a four wire (heated) Heated oxygen sensors have an internal heater circuit that brings the sensor up to operating temperature more quickly than an unheated sensor. The exhaust from the engine heat to brings the  O2 sensor up to operating temperature, but it make take several minutes depending on ambient temperature, engine load and speed. During this time, the fuel feedback control system remains in "open loop" and does not use the O2 sensor signal to adjust the fuel mixture. This typically results in a rich fuel mixture, wasted fuel and higher emissions.

The newer, Heated 02 Sensors being used bring them up to temperature within 60 seconds and maintains the heat at extended idling making the Engine much more "environmentally friendly".

In a Harley-Davidson System removing the CAT does not affect the Fuel Tables. For now. Rumor is they're going to a two sensor system in the coming years for all their products.



Tom