2007 Sportster Idler Air Control Issue

[Jack Klarich]

Thanks! That just may be it. Until I come across a set of schematics for a 2007 Sporty, I will be scratching my head. I need to know why & how a shorted system relay could possibly cause an IAC stepper to Buzz.

Maybe just maybe a stepper motor was not actually used on that year/model. An ordinary servo motor could have been used also. That would explain the entire phenomenon to me. I bet that's what it is because source power would then come off the System relay.

Electrical feedback? HMMM

 

[nvsteve]

Thanks! That just may be it. Until I come across a set of schematics for a 2007 Sporty, I will be scratching my head. I need to know why & how a shorted system relay could possibly cause an IAC stepper to Buzz.

Maybe just maybe a stepper motor was not actually used on that year/model. An ordinary servo motor could have been used also. That would explain the entire phenomenon to me. I bet that's what it is because source power would then come off the System relay.

There were some issues with the 07 IACs. I don't think there was ever a SB on them but non the less there have been some high idle issues. My valve needs cleaning once in a while to prevent a low idle stumble.

 

[orgredneck]

Thanks! That just may be it. Until I come across a set of schematics for a 2007 Sporty, I will be scratching my head. I need to know why & how a shorted system relay could possibly cause an IAC stepper to Buzz.

Maybe just maybe a stepper motor was not actually used on that year/model. An ordinary servo motor could have been used also. That would explain the entire phenomenon to me. I bet that's what it is because source power would then come off the System relay.

Hoople
I uploaded 2008 service manual
to downloads section this summer.
maybe this will help

the part # 31601-04 for my 09 was 12.00

 

[Hoople]

Hoople
I uploaded 2008 service manual
to downloads section this summer.
maybe this will help

Thanks, I took a look & I guess this will just have to remain an unanswered question for me. According to the schematics the system relay drives only the coil pack, injectors & fuel pump. The IAC is a 2 phase (4 wire) stepper motor that needs software instruction sets to rotate that is driven by the ECM.

None the less I am certainly glad the OP resolved the issue with his bike. The IAC stepper must not actually be rotating and is just "locked rotor" due to 1 phase being energized from the leaky system relay? (who knows)