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High rpm on cold start-up

Started by Ken R, April 02, 2020, 04:18:02 PM

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Ken R

What do you suppose is the purpose of the high RPM when starting an M-8 engine. 
My 2019 revs up to 2,800 to 3,000 RPM upon start-up, stays close to that for 2 to 4 seconds before reducing itself down to about 1,500 RPM over the next 5 to 10 seconds or so before it finally gets down to 1,000 RPM. 

It seems that revving a cold engine right after starting it would be bad news. 

We can't tune the cold start RPM without totally and completely violating the warranty.

The high RPM on start-up is annoying to me; and it seems like it would be detrimental to the engine.

kd

Complain to the dealer about the chance of engine damage and see if they deal with it on warranty.  I don't think it can be set up without the SE tuner. Depending on the temperature  (how cold is it where you are) it appears 1800 to 2200 is the norm.  I think yours is too high and it might be an intake or other influence. I personally would insist on a check over in the shop and a work order cut so you'll have a record of it.  The warranty you are going through great pains to maintain won't be worth anything if it kills your engine 2 months after it expires.  I don't think that they will say they all do that because it is about 1,000 rpm on the high side.  Hopefully other M8 owners will offer their experience on cold starting rpm.
KD

cbumdumb


kd

Quote from: cbumdumb on April 03, 2020, 06:36:08 AM
All three of my m8's did this.

Did ?  or still do this?  Did you report it to the dealer?
KD

Pirsch Fire Wagon

Poly Intake Leak - see it a lot - You can try tighten with a 3/16" Allen - But don't over tighten.
Tom

kd

 :up:  Likely the source of a lot of extra heat too.
KD

Ken R

Quote from: Pirsch Fire Wagon on April 03, 2020, 07:19:53 AM
Poly Intake Leak - see it a lot - You can try tighten with a 3/16" Allen - But don't over tighten.

I hadn't thought of that.  And it makes sense that a little warm up might close the leak a bit. 

moose

mine does it too can't see any intake leak, but going to change over to the cast one soon
Moose aka Glenn-

Durwood

A Crank to Run adjustment will cure the issue. I would start with a 20% reduction and go from there.

cbumdumb

Smoke and ultrasonic test show no intake leak. I may be wrong but believe it is emissions tuning to get bike up to steady idle to help meet emissions.

Jamie Long

Quote from: Ken R on April 02, 2020, 04:18:02 PM
My 2019 revs up to 2,800 to 3,000 RPM upon start-up, stays close to that for 2 to 4 seconds before reducing itself

Reving to 3K at startup is by no means normal. There is an air leak or other underlying issue. 

boggart

This is what I've read on this subject


To reset your idle setting back turn the ignition switch on for 10 seconds off for 10 seconds (do not start the engine), repeat a total of 4 times. That should reset your original throttle position.

The throttle by wire will remember throttle position each time the bike is shut down. some are having problems rolling the throttle a bit when using the kill switch

This can cause this type of problem

kd

Quote from: Jamie Long on April 06, 2020, 05:51:18 PM
Quote from: Ken R on April 02, 2020, 04:18:02 PM
My 2019 revs up to 2,800 to 3,000 RPM upon start-up, stays close to that for 2 to 4 seconds before reducing itself

Reving to 3K at startup is by no means normal. There is an air leak or other underlying issue.


:up:  That was my first thought too.  I would make use of the warranty.
KD

lucasg

April 07, 2020, 09:12:49 AM #13 Last Edit: April 07, 2020, 05:37:33 PM by FSG
Quote from: boggart on April 06, 2020, 06:30:50 PM
This is what I've read on this subject


To reset your idle setting back turn the ignition switch on for 10 seconds off for 10 seconds (do not start the engine), repeat a total of 4 times. That should reset your original throttle position.

The throttle by wire will remember throttle position each time the bike is shut down. some are having problems rolling the throttle a bit when using the kill switch

This can cause this type of problem


This occurred to me on my first road trip on my 2008 Street Glide.  Bike had barely 600 kms on it.  Called the dealer and walked my through the ignition cycling sequence and it did solve the problem.  Only difference was that the high idle wouldn't come down....

Sorry ....forgot this was an M8 bike.  Different system ??

HD/Wrench

most common reason is plastic manifold is leaking air I have seen several dozen last year alone .  Ken I am guessing this is a new issue ?? or after you had it tuned ?  ZERO reason to not be setting up IAC cold start steps at each and all temp levels at that current time .  You can only get it so cold but a few tricks to lower it further a bit .


TXChop

Just had this one in. 3000rpm idle. Customer cooked it. See the warp and the pitting/melted gasket.

Ken R

Quote from: HD/Wrench on April 11, 2020, 02:05:53 PM
most common reason is plastic manifold is leaking air I have seen several dozen last year alone .  Ken I am guessing this is a new issue ?? or after you had it tuned ?  ZERO reason to not be setting up IAC cold start steps at each and all temp levels at that current time .  You can only get it so cold but a few tricks to lower it further a bit .

New stock issue.  Can't get it professionally tuned with my PowerVision without voiding the warranty.  And I do too much highway travel to far away places to take that risk.

HD/Wrench

well if I recall that is a setting that can be adjusted in the Street  tuner . not had that program on my computer in many years ,  its cold start fuel IAC steps and then your underlying ve  number in closed loop

rigidthumper

Not any more- here is a screen grab of all the tables:
Ignorance is bliss, and accuracy expensive. How much of either can you afford?

HD/Wrench

well there you have it , It was listed at one point  I guess its been removed . Run a TTS no issues on the digital tech seeing the new tuner ( you must but it back to stock )

kd

Ken, did you ever resolve this?
KD

jls 64

js

Hillside Motorcycle

Once the plastic manifold bikes are tuned, the heat seems to be much tamer, resulting in usually a non-issue.
Otto Knowbetter sez, "Even a fish wouldn't get caught if he kept his mouth shut"

Pirsch Fire Wagon

Tom

cbumdumb

Weird was at dealership this morning as they were starting new bikes and every one did it some a little higher than others ... so not going to worry about it . Most of the dealership modded bikes seemed to rev a few hundred rpm more than stock ones .  :idunno:

PJPower05

I had the exact same issue.  I found the fix by resetting the Throttle Position Sensor.  You do this by turning the ignition switch on for 10 seconds then off 10 seconds.  Repeat 4 times.  Do not touch the throttle when doing it.  Worked like a charm.

Deye76

What's the problem with a high idle for a couple seconds? Oil circulation?
East Tenn.<br /> 2020 Lowrider S Touring, 2014 CVO RK,  1992 FXRP

sandrooney

Mine starts up at about 1500, then goes down as it warms up. Start up at 3000 seems a little high before oil is pumped up good. I am not thrilled with 1500.
Patience is such a waste of time .

Deye76

"seems a little high before oil is pumped up"
Not to worry, these motors don't need hardly any oil pressure.  :wink:
East Tenn.<br /> 2020 Lowrider S Touring, 2014 CVO RK,  1992 FXRP

Ken R

Quote from: kd on April 30, 2020, 07:20:12 PM
Ken, did you ever resolve this?

No, never resolved. 
I know that the cold start idle can be adjusted with my PowerVision, but I don't want to void my motorcycles warranty.  The radio may break under warranty.  :wink:

Motorcycle engine runs perfectly after a few seconds.  Within 15-20 seconds, down to about 1,100 RPM.  A few minutes later, oscillates around 950 to 1000. 

It's just that initial start up that's annoying and seemingly unnecessary.

Ken