Lean spike when engaging clutch releasing throttle

s300 and SManager software questions & answers
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xzone007
Posts: 2
Joined: Thu Oct 29, 2020 12:42 pm

Lean spike when engaging clutch releasing throttle

Post by xzone007 »

I am having a strange lean spike when letting off the throttle specifically when engaging the clutch. The RPMs drop quickly and the drops quickly, not sure if this would be the cause of the issue, but it spikes lean for a second and then resettles. It is rich before and idle is slightly rich also trying to get it to not spike. Attached is my tune and ~6 minute data log. You can see the most noticeable instances at 3:48 and 4:53 where I am in gear and then depress the clutch to coast.

2:52 is an example when shifting and using throttle after but if you view gear shifts on the datalog you can see almost all instances of when pressing the clutch to shift the RPMs drop and it spikes and then recovers quickly back to normal. It looks like it is falling into cells and spiking in cells where it normally runs correctly so I am not sure if the fuel map is the issue or if the issue is elsewhere. Thank you for any assistance.

Current setup:
10:1 b18c with forged rods and pistons
Skunk2 Pro1 cams and full valvetrain
1300cc Deatswerks Injectors and E85
GTX3076r turbo
Attachments
Datalog-210725-131140.s3d
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Current.skl
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Spunkster
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Posts: 22737
Joined: Fri Sep 20, 2002 5:06 pm
Location: Hondata

Re: Lean spike when engaging clutch releasing throttle

Post by Spunkster »

This looks completely normal.
xzone007
Posts: 2
Joined: Thu Oct 29, 2020 12:42 pm

Re: Lean spike when engaging clutch releasing throttle

Post by xzone007 »

Thank you for the response, I expect to see it spike during decel when the injector time goes to 0 and engine braking but seeing it spike then return just when engaging the clutch and coasting within normal/idle fuel cells was concerning and I was not sure if timing or one of the parameters I was unfamiliar with needed adjustments or if that was a sign of slow wideband response, misfire, etc. Trying to learn as much as possible and understand what to look for and identifying issues. Thank you again.
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