Ducati Monster Forum

powered by:

March 29, 2024, 02:16:33 AM *
Welcome, Guest. Please login or register.

Login with username, password and session length
News: Welcome to the DMF
 
   Home   Help Search Login Register  



Pages: 1 [2] 3 4   Go Down
  Print  
Author Topic: Revs fall slowly - not enough engine braking  (Read 10926 times)
koko64
Post Whore
******
Offline Offline

Posts: 15650


« Reply #15 on: August 06, 2022, 11:31:59 PM »

Check the injector seals too.  Also could be slightly leaking injectors or the throttle plate not coming to it's proper position due to dirt.

Yeah, there can be a line showing a ridge of dirt build up.
Logged

2015 Scrambler 800
2004 GSXR 750
greenmonster
Hero Member
*****
Online Online

Posts: 1281


« Reply #16 on: August 07, 2022, 01:20:27 AM »

Shot in the dark:
How long since TPS reset?
Logged

M900 -97 
MTS 1100s  -07
koko64
Post Whore
******
Offline Offline

Posts: 15650


« Reply #17 on: August 07, 2022, 01:40:16 AM »

Shot in the dark:
How long since TPS reset?

Worth doing all that stuff after a rebuild.
Logged

2015 Scrambler 800
2004 GSXR 750
stopintime
Hero Member
*****
Offline Offline

Posts: 8912


S2R 800 '07


« Reply #18 on: August 07, 2022, 07:24:17 AM »

I'm pretty sure that the idle speed is adjusted with the air bleeds, but I'm not a fuelie guy.

There may be a stop screw. Check with the shop.

There is a stop screw VERY well hidden between the two body halves. LT Snyder describes the diagnostic software in a chapter about trim - it has a box for idle speed, but without a stepper motor I don't understand how the ECU can regulate idle speed.... maybe with fuel?  Again; the shop will hopefully tell me what they did / didn't do / forgot.

... aaand we have the air bleeds.


Check the injector seals too.  Also could be slightly leaking injectors or the throttle plate not coming to it's proper position due to dirt.


I checked that they are well mounted. Just a tiny bit of wiggle - as expected from items with ok seals. They could still be leaking, so I'll keep them on the list for a day when I have time and courage to dig my way to them ...  Throttle butterflies, or rather the intake where they operate, were cleaned not so long ago and they slam shut, but will put them on the list too ...


How many turns out are the TB air screws?

Don't know. I'll check with the shop before I decide if they might need adjustments.


Shot in the dark:
How long since TPS reset?

Ages. Recently. Shop will know. Work Shop manual states that it must be reset after a replacement (means no need unless...?) Maybe if someone knocked it out of place or if wires/connectors are up for renewal ...


Logged

237,000 km/sixteen years - loving it
Orange16
New Member
*
Offline Offline

Posts: 44


« Reply #19 on: August 10, 2022, 03:42:09 AM »

Which model is it?

Has it changed after recent work?

If it doesn't have a stepper motor then the air bleeds control the idle speed.  Wind them in to lower the idle.  That will most likely help with the slow return to idle too.

Changing the air bleed setting will change the idle mixture, so it's a two step process.

Changing the ignition advance in the idle map is another way to change how they return to idle, but that's a more advanced step and not something that changes.
Logged
stopintime
Hero Member
*****
Offline Offline

Posts: 8912


S2R 800 '07


« Reply #20 on: August 20, 2022, 10:44:40 AM »

The shop is closed another two weeks.


Similar weather and similar engine temperature:

It no longer fluctuate to 2,500 revs. Now only to 2,000 and maybe a little less often.

After reving it, it slowly'ish settles at 2,000 and after another two three second to 1,500. So, the reduced engine breaking is still a problem.

I checked the air bleeds today. They were all the way in. Tried one full turn out (yes, a 360) = nothing. Another half turn = nothing. Another full turn = nothing. All the way in = nothing.  Maybe, just maybe, a little crisp'er throttle response with the bleeds out (MAYBE).

I'll throw in another factor.... not at all scientific, but I get the impression that it gets warmer during city riding. Maybe 5-10 degrees C. I'm curious to hear what the shop might have changed, if anything. Maybe something in the ECU fuel/spark maps.... to control the bike's temperament a little... 
Logged

237,000 km/sixteen years - loving it
koko64
Post Whore
******
Offline Offline

Posts: 15650


« Reply #21 on: August 28, 2022, 02:34:00 AM »

Any news?
Logged

2015 Scrambler 800
2004 GSXR 750
greenmonster
Hero Member
*****
Online Online

Posts: 1281


« Reply #22 on: August 28, 2022, 05:47:20 AM »

Quote
    I'm curious to hear what the shop might have changed, if anything. Maybe something in the ECU fuel/spark maps.... to control the bike's temperament a little...

https://bradthebikeboy.blogspot.com/2019/07/multistrada-1000-not-idling-ecu-based.html?m=1

Longish but fix at end might interest.
« Last Edit: August 28, 2022, 08:51:09 AM by greenmonster » Logged

M900 -97 
MTS 1100s  -07
stopintime
Hero Member
*****
Offline Offline

Posts: 8912


S2R 800 '07


« Reply #23 on: August 28, 2022, 01:17:04 PM »

Any news?

Hopefully this coming week.



Well... I don't have a stepper, so ......
Logged

237,000 km/sixteen years - loving it
greenmonster
Hero Member
*****
Online Online

Posts: 1281


« Reply #24 on: August 28, 2022, 03:26:52 PM »

You are courius if shop altered ignition map, you said.
Logged

M900 -97 
MTS 1100s  -07
stopintime
Hero Member
*****
Offline Offline

Posts: 8912


S2R 800 '07


« Reply #25 on: September 14, 2022, 09:45:18 AM »

Shop replied and suspect TPS - at least as a primary suspect.

I had the TPS checked and reset twice. 2.5 (mV?) both times. So, it's not the TPS.

The vertical cylinder's plug is showing signs of lean running. The copper spacer (to lift the plug off the piston) is squashed and maybe there was false air sucked in. You can see that the threads are dry and clean. I don't know if that's possible, but the signs are clear. The other major sign is that the 'tip' from inside the ceramic is no longer a tip. It's gone / reduced down to the level of the ceramic.

The horizontal cylinder's plug is more or less normal.

VERTICAL









HORIZONTAL
Logged

237,000 km/sixteen years - loving it
ducpainter
The Often Hated
Flounder-Administrator
Post Whore
*****
Offline Offline

Posts: 78191


DILLIGAF


« Reply #26 on: September 14, 2022, 02:58:25 PM »

How many miles on those plugs?
Logged

"Once you accept that a child on the autistic spectrum experiences the world in
 a completely different way than you, you will be open to understand how that
 perspective
    is even more amazing than yours."
    To realize the value of nine  months:
    Ask a mother who gave birth to a stillborn.
"Don't piss off old people The older we get, the less 'Life in Prison' is a deterrent.”


koko64
Post Whore
******
Offline Offline

Posts: 15650


« Reply #27 on: September 14, 2022, 04:40:38 PM »

Shop replied and suspect TPS - at least as a primary suspect.

I had the TPS checked and reset twice. 2.5 (mV?) both times. So, it's not the TPS.

The vertical cylinder's plug is showing signs of lean running. The copper spacer (to lift the plug off the piston) is squashed and maybe there was false air sucked in. You can see that the threads are dry and clean. I don't know if that's possible, but the signs are clear. The other major sign is that the 'tip' from inside the ceramic is no longer a tip. It's gone / reduced down to the level of the ceramic.

The horizontal cylinder's plug is more or less normal.

VERTICAL









HORIZONTAL


Shit!  How's compression on that cylinder? I wonder if an air leak has melted it away (or runaway ignition timing issue). Yet the side electrode appears dark. If ignition advance got away it would be white along its length well past the half way mark (unless oil has since stained it dark).

Howie to the courtesy phone!
« Last Edit: September 14, 2022, 04:47:03 PM by koko64 » Logged

2015 Scrambler 800
2004 GSXR 750
Howie
Post Whore
******
Offline Offline

Posts: 16809



« Reply #28 on: September 14, 2022, 05:02:29 PM »

Ummm....wow!

For sure you want to start with a compression test.  If compression is good enough, then injector volume and pattern.  I do think koko's thoughts on the air leak is probably it.  I don't like the looks of the copper "spacer", could be the problem. 
Logged
stopintime
Hero Member
*****
Offline Offline

Posts: 8912


S2R 800 '07


« Reply #29 on: September 15, 2022, 12:16:38 AM »

How many miles on those plugs?

I din't know. They were probaly replaced this summer = 5,000 mies. Last summer.... ~15,000



Shit!  How's compression on that cylinder? I wonder if an air leak has melted it away (or runaway ignition timing issue). Yet the side electrode appears dark. If ignition advance got away it would be white along its length well past the half way mark (unless oil has since stained it dark).

Howie to the courtesy phone!

Compression was good, but that was without the squashed copper spacer issue (during the test procedure)


 
Ummm....wow!

For sure you want to start with a compression test.  If compression is good enough, then injector volume and pattern.  I do think koko's thoughts on the air leak is probably it.  I don't like the looks of the copper "spacer", could be the problem. 

New plugs and new spacers yesterday, so I'll check in a few days. The idle is still too high (especially between 60-80 degrees C)(~140-180F).

The fuel map was done (or maybe just confirmed) after the last work in July. Good A/F ratio all along the range. That Dyno work also showed improved peak power and beautiful curves all along the rev range. Even so, I can't reach the top speed I used to. Missing almost 15mph.

Something is not quite right.
Logged

237,000 km/sixteen years - loving it
Pages: 1 [2] 3 4   Go Up
  Print  
 
Jump to:  


Powered by MySQL Powered by PHP Powered by SMF 1.1.21 | SMF © 2015, Simple Machines
Simple Audio Video Embedder
Valid XHTML 1.0! Valid CSS!
SimplePortal 2.1.1