Hard start when warmed up
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1st Gear
Joined: Aug 2021
Posts: 5
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From: Grenada, MS
Hard start when warmed up
I have an 09 Dyna Street Bob that is giving me issues on cranking. It starts fine when cold, but I have to burp the throttle when its warmed up. Its a Twin Cam. Changed the filters. I can hear the fuel pump when I turn the key on.
On a Fuel Injected bike ?
Seasoned HDF Member
Joined: Sep 2017
Posts: 12,254
Likes: 4,947
From: England
On a fuel injected bike there is a temperature sensor. In the software there is a table that contains amounts of enrichment based on temperature. There is also a table specifically for how much petrol to inject during the starting procedure.
Last edited by Andy from Sandy; Sep 4, 2022 at 06:12 AM.
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Joined: Jan 2007
Posts: 15,788
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From: along the shore of Mishigami
The temp sensor is on the back,left side of the front cylinder. Pull the connector give it good cleaning, a dirty plug will increase the resistance ultimately changing the resistance value to the hot circuit side of the ECM.
Seasoned HDF Member
Joined: Mar 2010
Posts: 21,116
Likes: 7,638
From: Poolville
Wouldn't hurt to get a Power Vision tuner, then you can see exactly what it's doing.. Great tool. You can pretty much change anything you want to get it running cool with better power.
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From: Honah Lee
Just a long shot but since it starts fine cold, the IAC is giving it more air. So that's probably fine. Check the temperature sensor in the throttle body. Also, open the butterfly and use a cotton cloth wetted with throttle body cleaner to clean around where it snaps closed. That's a set metered airflow. It and the IAC combined work together for starting and idle.
Be sure the throttle position switch is not frozen. Just spraying a bunch of cleaner in there kills the TS, TPS, and IAC motor by washing crud into them.
Be sure the throttle position switch is not frozen. Just spraying a bunch of cleaner in there kills the TS, TPS, and IAC motor by washing crud into them.
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