Gen 1 Wont Idle

[CJawn]

Hi guys, Im having an issue with my bike and hoping yall can help.
2005 Hayabusa
Stock other than shortys
The bike would not rev above 9k so I cleaned injectors and now the bike will not idle above 900 rpms. as soon as i turn the idle screw up it dies, along with turning on the fast idle. Behaves fine with throttle, and will rev out cleanly. When i first start it it stays on for like 30 seconds at like 1100 rpms when its cold starting, but once it switches to idle from cold start it slowly drops to 900 then dies. Ive tried replaced the fuel pump, tps, ive checked all vacuum hoses and airbox is fully seated on the throttle bodies. Injectors were professionally cleaned and spray/leak tested. Any help would be great because im about to take it to a shop.

 

[Hayabusa Wannabe]

Welcome to the forum @CJawn.

 

[sportbikeryder]

Does it have any fault codes? Sort of sounds likea Map sensor issue (IAP sensor) if it is only having issues at idle.

You can try spraying a carb cleaner or similar around the outside of teh TB's and hoses while running, without gatting any in intake tract itself. If the idle changes at all, there is likely a vacuum leak somewhere.

 

[CJawn]

No fault codes on dash, should i try replacing the IAP?

 

[202mphbusa]

No fault codes on dash, should i try replacing the IAP?

Dissconet it and see if any change
Does kinds sound like map
maybe map and baro plugs swapped

 

[two valleys moto]

Welcome. If you haven't done so make sure the charging system is good. Namely the regulator. A Busa will still run, albeit like garbage, when the reg/rec is going kaput. Just encountered that. Thought I was having fuel delivery issues. Turned out the reg/rec was going bad. I also encountered the kickstand switch gremlin. Wouldn't pull over 6-7k at all. Thought once again it was having fuel delivery trouble. After reading through a lot of posts on here I saw enough kickstand switch problems to cut and splice the wires together. She screamed stariaghtaway after that! Hope ya get it sorted. Should be pretty simple.

 

[zucchero]

Dissconet it and see if any change
Does kinds sound like map
maybe map and baro plugs swapped

Sorry to ask but by map did you mean the AFR fuel map in ECU or is it something else.
Asking because I keep reading all the post so as to gain some knowledge.

 

[202mphbusa]

There is a ambiant baro sensor bolted inside the LH frame rail. A little awkward but possible to swap then

I would unplug the map sensor and see if it runs different

 

[CJawn]

Unplugged Boost sensor at the back of the airbox and it idled just fine, have a new sensor on order and it should fix the issue.