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Discussion Starter #1
Ok so my buddy has been having some starting problems on his 550xp. It will start but only if you feather the gas while trying to start it and it runs rough / won't idle until its warmed up then it seems like everything is fine.

So far from searching the forums i have checked the following out:

Cdi plastic clip connectors are good
Coil is working perfect
Its getting fuel because you can smell it being dumped
tried two different spark plugs
Tried different gas
compression tested and its over 75 everytime
dielectic greased most of the connectors
checked for grounds being off with the starter


Anything else we should check? Its completely ripped apart right now so everything is pretty easy to check.

Heres a quick video of what its doing.
 

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Throttle cable adjustment?
Fuel pump?
 

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Discussion Starter #4
No codes are showing up at all. Fuel pump is fine and cable is fine as well. Once its warmed up it acts like nothing is wrong at all.
 

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...given the look of the bike being either extremely dusty or just out of some mud hole, plus the comments on the smell of gas/dumping fuel, my bet would be the air filter is is plugged up good. A dirty air filter will make it hard for the engine to breathe and that would be every apparent during a cold start due to the ECU dumping fuel to keep it rich until temp comes up. The IAC will then start to lean out the fuel by air volume coming in. You adding "gas" by the throttle is opening up the throttle body, allowing to engine to slightly breathe better allowing combustion...albeit poorly. Have you checked that during the tear down?
 

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Once the motor reaches operating temp. It relies on air intake temp and map or the TMAP sensor for proper air fuel ratio. While cold it's working off preset perimeters in the ECM . It's the job of the IAC TO keep it running.

Mounted in front of the engine, the IAC contains 1 stepper motor which receives varying voltage signal pulses from the ECU. These pulses determine the IAC plunger setting, thereby controlling the amount of air bypassing the closed throttle body for idle control. If the IAC is disconnected or inoperative, it will remain at it’s last operated position.
IAC Test
The IAC is a non-serviceable item. If it is faulty, it must be replaced. It can be ‘bench tested’ using the following method:
Set your meter to read Ohms. Check the resistance values at each of the following pin locations of the IAC. If any of the readings are out of specification, replace the IAC
IAC Valve Connector
456 123

IAC Resistance Readings
Pins
Resistance
Pins
Resistance
1-2
30Ω ± 1.2Ω
4-5
30Ω ± 1.2Ω
2-3
30Ω ± 1.2Ω
5-6
30Ω ± 1.2Ω
1-3
60Ω ± 2.4Ω
4-6
60Ω ± 2.4Ω

The strong smell of gas is the IAC not opening or a restriction in one of its lines.


12 850EPS
 

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Discussion Starter #9
Its at the dealership now they think its the throttle body i'll let you guys know when its done.
 

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Discussion Starter #10
Forgot to update this. The starting problem ended up being something wrong with the spark plug wire. Nothing was wrong visually but apparently it was bad somehow because as soon as it was replaced it fired right up but still idled weird. The intake valve was really tight so it was loosened up and now its running better than it did the day we got it. A lot of people have responded to the video also having valve problems.
 
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