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tfi install for a 2009 sportster 883l

M

mikes harley

Member
Ok i need help with my tfi i have 2009 sportster 883l and i found the factory injecters, butt on the tfi how do you now where they plug in at, there not labeled front and rear only the factory wires are. So my question is on the tfi witch one is the front connections for the injectors and wht one is for the rear injectors the directions dont explain much here on tht issue. I now theres four injector wires to plugg in butt whts front, and whts back on the tfi ,on one side the wires are long and the other side the wires are short.
 
I can understand how the TFI stretches out the pulse duration of an injector with different windows of RPM bands, but what I don't understand is why doesn't the ECM throw a code for the O2 sensors staying rich and not toggling. I would think the entire time the TFI is making the engine more rich, the Factory ECM is wondering why the O2 is always on the rich side and eventually throw a code that the O2 sensor is stuck at a rich value. In all the cells of the A/F map where the ratio should be stoichiometric (~14.7) I can see the ECM going crazy.
 
Thanks Steve. Now I understand. I don't know much about those unit's as I am sure you can tell.!
 
Hoople said:
I can understand how the TFI stretches out the pulse duration of an injector with different windows of RPM bands, but what I don't understand is why doesn't the ECM throw a code for the O2 sensors staying rich and not toggling. I would think the entire time the TFI is making the engine more rich, the Factory ECM is wondering why the O2 is always on the rich side and eventually throw a code that the O2 sensor is stuck at a rich value. In all the cells of the A/F map where the ratio should be stoichiometric (~14.7) I can see the ECM going crazy.
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I had the same question and e-mailed Doebeck, the answer Chris gave is that the voltage reading picked up by the O2 sensor is altered with a resistor and that value is considered unreliable by the ECU so it disregards it in the calculation of AFR. My understanding is that this is a little bit richer AFR even without adding any in the pots, but the important part is that the change in exhaust gas composition doesn't alter the AFR back to a lean condition. He never explained why no code.
 
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