Hot starts and idle
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Grand HDF Member
Joined: Sep 2017
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From: Dubuque, IA
Hot starts and idle
I've noticed an issue and I'm not quite sure when it surfaced but after I'm running and warmed up, if I shut down and restart 10 minutes later while still warm my idle will drop momentarily then recover. I'm not sure if it's related to my rich AFR I'm running or if advancing the timing from 16° to 18° but I think it might be the fuel. This is when I really noticed my compensator was junk as it would clunk and knock. Since replacing it with a solid 30 tooth I get no more of that but my idle still drops momentarily. It revovers after a couple seconds. It's not an issue on cold starts.
I'm thinking of playing with cranking fuel in the Super Tuner Pro but Im not really familair with that paramenter.
Thoughts?
0h yeah, specs. S&S 570s on a stock 2013 103. Cranking compression 190psi. Running open loop and idle AFR at 13.2.
I'm thinking of playing with cranking fuel in the Super Tuner Pro but Im not really familair with that paramenter.
Thoughts?
0h yeah, specs. S&S 570s on a stock 2013 103. Cranking compression 190psi. Running open loop and idle AFR at 13.2.
Last edited by 60Gunner; Jul 11, 2020 at 06:54 PM.
Cruiser
Joined: Aug 2016
Posts: 247
Likes: 59
From: California
Is the tuning on your bike new? If not, then it's probably not a new issue related to tuning. Get the bike hot, and in whatever condition you normally have an issue, hook up your tuner, and record the data items screen (while it experiences this issue, you may have to try it until it does), and see if your engine temperature number is steady, and doesn't go from a normal operating temp, to 3 degrees.
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Grand HDF Member
Joined: Sep 2017
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Likes: 1,219
From: Dubuque, IA
Yes the tune is new and has been an ongoing process with the AFR and timing. Especially idle and lower rpm fuel and timing. I had a halfway decent dyno tune. I say that because he did a really thorough job dialing in the VE tables which is critical to getting the desired AFR that you set and he tuned the WOT AFR but not the cruise or part throttle AFR. At least not good enough. Left the cruise and idle way too lean. I've since gone 100% open loop adding fuel and timing to help with cooling. It runs great. Just stumbles at warm startup briefly like it's too much fuel. IAC maybe?
Cruiser
Joined: Aug 2016
Posts: 247
Likes: 59
From: California
Is it stumbling during an otherwise fairly steady idle? I would still check ET numbers, they fail more regularly than IAC's, and will cause you to chase your tuning around, especially since your tuner should be able to show you that data.
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Grand HDF Member
Joined: Sep 2017
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From: Dubuque, IA
I'll do another data run. Well actually just a start up. Now today it wasn't bad. Dropped to 900 initially then right up to 1050. Another time it was fine. I did clean the IAC but nothing really came out black. It's a very minor thing but something I notice.
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Grand HDF Member
Joined: Sep 2017
Posts: 4,359
Likes: 1,219
From: Dubuque, IA
I do believe I've found the answer in the SE Pro Super Tuner manual. Since I added fuel, I'm pretty sure I need to increase the IAC warm up steps. In fact I'm almost certain.
IAC Warm-up Steps
The IAC Warm-up Steps table is used to provide an additional amount of air to the engine for its first several minutes of operation.
o
Higher numbers increase airflow to the engine at idle.
o
Lower numbers decrease airflow to the engine at idle.
TIP:
Use IAC Warm-up Step Table to improve engine idle performance during warm-up. If engine RPM increases and then decreases just after start up, IAC steps may be set too highfor this engine temperature. If engine RPM dips and then increases just after start up, IACsteps may be set too low for this engine temperature.
IAC Warm-up Steps
The IAC Warm-up Steps table is used to provide an additional amount of air to the engine for its first several minutes of operation.
o
Higher numbers increase airflow to the engine at idle.
o
Lower numbers decrease airflow to the engine at idle.
TIP:
Use IAC Warm-up Step Table to improve engine idle performance during warm-up. If engine RPM increases and then decreases just after start up, IAC steps may be set too highfor this engine temperature. If engine RPM dips and then increases just after start up, IACsteps may be set too low for this engine temperature.
Last edited by 60Gunner; Jul 18, 2020 at 04:45 PM.
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