LML Twins and Opinions

FROGMAN524

FROGMAN524

Member
Jul 17, 2010
613
4
18
So without raising my idle to fix the slight vibration I’ve been having I have a question about a different way to go.

When I’m driving in town and let off the throttle under about 55MPH and coast, like coasting to a stop light, the RPMs drop and stay at about 750 until I’m at a complete stop and then they drop to 640 which is normal idle speed. Is there a way to make them drop to 640 while coasting? 750 is the vibration sweet spot so it’s quite annoying.


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N2BRK

N2BRK

Well-known member
Dec 31, 2009
2,066
399
83
there is on the LMM, so it seems reasonable that there might be.
 
FROGMAN524

FROGMAN524

Member
Jul 17, 2010
613
4
18
I’m sure it’s a tuning thing if it can be done. Is there a reason the LML does this?


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JoshH

JoshH

Daggum farm truck
Staff member
Vendor/Sponsor
Feb 14, 2007
13,736
806
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Texas!!!
I haven't found anything to prevent them from randomly doing an 800-850 RPM high idle sometimes. I doubt there is anything in EFILive to do what you want, but I'm sure there is something in there if someone had the time and patience to dig through the hex code to find it. That is something way outside my payscale though.
 
FROGMAN524

FROGMAN524

Member
Jul 17, 2010
613
4
18
Unless you’re at a complete stop it stays at 750 or so when coasting with the converter unlocked.


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PureHybrid

PureHybrid

Isuzu Shakes IT
Feb 15, 2012
3,517
501
113
Central OH
I'm sure it will never truly get back down to idle speed, the driveline will push the engine a little unless the converter is really loose.
 
kidturbo

kidturbo

Piston Tester
Jul 21, 2010
2,552
1,401
113
Somewhere On The Ohio
www.marinemods.us
Haven't looked in an LML file for a bit, but as stated above, the LMM has a table where idle speed can be adjusted based off VSS reading zero or not. Sounds like that's the one ya need to change.

Other option, a push button momentary open switch stuck in the output shaft speed sensor signal wire on trans would accomplish the same. It's PWM so, no pulses, it thinks your stopped... I'd check option 1 first.. :thumb:
 
FROGMAN524

FROGMAN524

Member
Jul 17, 2010
613
4
18
kidturbo said:
Haven't looked in an LML file for a bit, but as stated above, the LMM has a table where idle speed can be adjusted based off VSS reading zero or not. Sounds like that's the one ya need to change.

Other option, a push button momentary open switch stuck in the output shaft speed sensor signal wire on trans would accomplish the same. It's PWM so, no pulses, it thinks your stopped... I'd check option 1 first.. :thumb:
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Thanks I’ll ask Blake about it


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S

S Phinney

Active member
Aug 15, 2008
4,008
18
28
Quncy, Fl
You have compounds in it right? If so the vibration is probably coming from the atmosphere bracket. There is some harmonics in some people systems. Do you have a bracket bolting it to the accessories cover?


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FROGMAN524

FROGMAN524

Member
Jul 17, 2010
613
4
18
Yes the 490 is bolted to the side of the block and that’s probably causing the harmonics. Not sure how to solve it besides changing idle to 800+


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S

S Phinney

Active member
Aug 15, 2008
4,008
18
28
Quncy, Fl
FROGMAN524 said:
Yes the 490 is bolted to the side of the block and that’s probably causing the harmonics. Not sure how to solve it besides changing idle to 800+


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Does the arm that’s holds the atmosphere have a bracket up top that bolts to the accessories cover? If not you can make one fairly easy and that will stop the harmonica you are experiencing.


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FROGMAN524

FROGMAN524

Member
Jul 17, 2010
613
4
18
S Phinney said:
Does the arm that’s holds the atmosphere have a bracket up top that bolts to the accessories cover? If not you can make one fairly easy and that will stop the harmonica you are experiencing.


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What’s the accessories cover? It bolts directly to the block and that’s it.


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S

S Phinney

Active member
Aug 15, 2008
4,008
18
28
Quncy, Fl
FROGMAN524 said:
Do you have a pic? I suspect I’d have to fabricate myself

These came in the HSP kit. Did you use their stuff or others? It wouldn’t be too hard to fabricate but if it’s HSP I could get you the items.
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