2008 250 randomly bogs on hard throttle
Post Reply    Forum -> MP3 Discussion
Author Message
Member
2008 MP3 250
Joined: 15 Jan 2019
Posts: 12
Location: FL
Tue Jun 23, 2020 12:57 pm quote
Hi all, Iíve been riding my new to me 250 for about a week now, some quick history: it sat for a year and a half before I bought it. 5200 miles on the clock. I drained the fuel that was in there and installed a new agm battery and new oem air filter. Has been running great but died immediately a few times on cold start up (A quick blip of the throttle after light off fixed that). Topped off the gas(91 octane) way too high Monday morning, didnít spill out but was maybe an inch from the top. Went to work and back, about 30 mins of total riding, no issues. Monday afternoon I removed and cleaned the throttle body and idle passage. Started up great, rode to work this morning, no issues, rode back a few hours later(Ambient temp around 90 in Florida) and the engine was bogging randomly when Iíd whack the throttle. Idles great, seemed fine if I slowly rolled it up to speed. My gas gauge is still a little past full. Pulled the gas cap off and it made a pfffffft noise.

Iíve read a few posts on driveability issues after an overfill related to the evap canister. My question is, if that is a potential culprit, will it go away as the fuel draws down or do I need to do something proactive like drain the evap can or something.

Thanks for reading!
Hooked
50cc Beo, BigBeo
Joined: 30 May 2015
Posts: 221
Location: Chelyabinsk, Russia
Tue Jun 23, 2020 10:14 pm quote
Pffff noise means that your gas tank produces vacuum
Seriously that means you should replace your tank cap or try to clean by compressed air maybe. Or (as a very temporary solution) try not to screw it too much, maybe air could pass through thread.
When you ride hard, vacuum becomes too much powerful and prevents enough fuel to reach your engine.
Ossessionato
Gilera Fuoco 500ie
Joined: 11 Oct 2009
Posts: 4174
Location: Netherlands Olst
Wed Jun 24, 2020 3:34 am quote
how much rpm s?
Member
2008 MP3 250
Joined: 15 Jan 2019
Posts: 12
Location: FL
Wed Jun 24, 2020 4:01 am quote
Iíd say it is between 3k and 5k. I think the rear wheel starts to spin around 3k right? It has happened with too quick a rev off the line and also at speed around 35-40mph. It bogs but always catches itself when I let off. The engine never dies. It isnít perfectly repeatable. I was messing around with it around my condo and sometimes I can give it the full beans and sometimes not. Iíll see if regularly venting the fuel tank makes a difference.
Ossessionato
Gilera Fuoco 500ie
Joined: 11 Oct 2009
Posts: 4174
Location: Netherlands Olst
Wed Jun 24, 2020 1:08 pm quote
oke fuelpump there was a recall for it
Member
2008 MP3 250
Joined: 15 Jan 2019
Posts: 12
Location: FL
Wed Jun 24, 2020 1:19 pm quote
It's going to a local authorized dealer/service center in 2 weeks for a coolant flush(that's how booked up they were!) so I'll mention it but looks like that recall is for 09-10 mp3 250's.

Road to work today around 11am with the gas cap slightly loose, no issues. Rode home around 330pm and it started acting up and I think I heard a pop/misfire out of the exhaust at one point. Almost feels like it doesn't like hot afternoons. I can slowly roll into 50mph no problem.

Ordered a new NGK CR8EKB plug so that will eliminate the plug as an issue.

Last edited by cmouta on Wed Jun 24, 2020 1:22 pm; edited 1 time in total
Moderaptor
The Hornet (GT200, aka Love Bug) and 'Dimples' - a GTS 300
Joined: 26 Aug 2007
Posts: 38616
Location: Pleasant Hill, CA
Wed Jun 24, 2020 1:22 pm quote
Maksor wrote:
oke fuelpump there was a recall for it
^^^^
This - get your dealer to check the VIN against the recall list. It may not be that, but it's worth making sure your fuel pump isn't one of the duff ones.

So you over-filled it? Had a vacuum in the tank? That points to the Evap Crap being clogged. It *should* eventually clear, but don't bet on it. Personally I'd remove it - I've done that to all my US bikes (which are the only ones up until very recently that had it).

So - moral of the story is never top off the tank! But do check for that recall...
Member
2008 MP3 250
Joined: 15 Jan 2019
Posts: 12
Location: FL
Wed Jun 24, 2020 1:53 pm quote
jimc wrote:
Maksor wrote:
oke fuelpump there was a recall for it
^^^^
This - get your dealer to check the VIN against the recall list. It may not be that, but it's worth making sure your fuel pump isn't one of the duff ones.

So you over-filled it? Had a vacuum in the tank? That points to the Evap Crap being clogged. It *should* eventually clear, but don't bet on it. Personally I'd remove it - I've done that to all my US bikes (which are the only ones up until very recently that had it).

So - moral of the story is never top off the tank! But do check for that recall...
So could I pull it and just...drain it and put it back in? Is the issue that the evap canister is full of gasoline? I've looked at the diagrams a few times but it's one of those things where I don't full grasp the plumbing until I'm in there looking at it.

I had a slight worry that when I was spraying throttle body cleaner into the throttle/idle air Controller port that somehow the cleaner drained into the ECU electronics although I can't imagine the IAC valve itself isn't sealed off from the rest of the ECU. Has anyone ever opened the ECU to check it out? I feel like I've read enough "I cleaned my TB and now it doesn't run right" posts to warrant that worry.
Veni, Vidi, Posti
MP3 500, GTS 250 (both 2008 MY), 2012 Honda NC700 DCT
Joined: 02 Mar 2013
Posts: 6019
Location: Madison, Wisconsin
Wed Jun 24, 2020 3:16 pm quote
cmouta wrote:
jimc wrote:
Maksor wrote:
oke fuelpump there was a recall for it
^^^^
This - get your dealer to check the VIN against the recall list. It may not be that, but it's worth making sure your fuel pump isn't one of the duff ones.

So you over-filled it? Had a vacuum in the tank? That points to the Evap Crap being clogged. It *should* eventually clear, but don't bet on it. Personally I'd remove it - I've done that to all my US bikes (which are the only ones up until very recently that had it).

So - moral of the story is never top off the tank! But do check for that recall...
So could I pull it and just...drain it and put it back in? Is the issue that the evap canister is full of gasoline? I've looked at the diagrams a few times but it's one of those things where I don't full grasp the plumbing until I'm in there looking at it.

I had a slight worry that when I was spraying throttle body cleaner into the throttle/idle air Controller port that somehow the cleaner drained into the ECU electronics although I can't imagine the IAC valve itself isn't sealed off from the rest of the ECU. Has anyone ever opened the ECU to check it out? I feel like I've read enough "I cleaned my TB and now it doesn't run right" posts to warrant that worry.
The evap canister is full of charcoal grains, which are intended to absorb fuel vapors only, not the liquid. When the engine is running there is a vacuum on the canister with a little air going through it into the engine, so the vapors de-sorb from the charcoal. When soaked with gas, like there is liquid gas in the canister, the air doesn't get drawn through it with the result there is a vacuum that develops in the fuel tank.
Member
2008 MP3 250
Joined: 15 Jan 2019
Posts: 12
Location: FL
Thu Jun 25, 2020 3:18 am quote
Madison Sully wrote:
cmouta wrote:
jimc wrote:
Maksor wrote:
oke fuelpump there was a recall for it
^^^^
This - get your dealer to check the VIN against the recall list. It may not be that, but it's worth making sure your fuel pump isn't one of the duff ones.

So you over-filled it? Had a vacuum in the tank? That points to the Evap Crap being clogged. It *should* eventually clear, but don't bet on it. Personally I'd remove it - I've done that to all my US bikes (which are the only ones up until very recently that had it).

So - moral of the story is never top off the tank! But do check for that recall...
So could I pull it and just...drain it and put it back in? Is the issue that the evap canister is full of gasoline? I've looked at the diagrams a few times but it's one of those things where I don't full grasp the plumbing until I'm in there looking at it.

I had a slight worry that when I was spraying throttle body cleaner into the throttle/idle air Controller port that somehow the cleaner drained into the ECU electronics although I can't imagine the IAC valve itself isn't sealed off from the rest of the ECU. Has anyone ever opened the ECU to check it out? I feel like I've read enough "I cleaned my TB and now it doesn't run right" posts to warrant that worry.
The evap canister is full of charcoal grains, which are intended to absorb fuel vapors only, not the liquid. When the engine is running there is a vacuum on the canister with a little air going through it into the engine, so the vapors de-sorb from the charcoal. When soaked with gas, like there is liquid gas in the canister, the air doesn't get drawn through it with the result there is a vacuum that develops in the fuel tank.
Thanks for the explanation. With the charcoal canister up so high, I couldnít figure out why it would fill with gas but I forgot it was hooked into intake manifold vacuum. I think I will pull it and see where it gets me.

Is there a desirable place to run the vent line? Seems like you wouldn't want fuel vapors evacuating on a hot exhaust, or near the intake pipe on the other side or near any hot brakes. I see the wiki says "route down into the frame" but I'd love to see a photo of where exactly.
Member
2008 MP3 250
Joined: 15 Jan 2019
Posts: 12
Location: FL
Sun Jun 28, 2020 6:27 am quote
Thanks for all the suggestions. Pulled the charcoal canister, plugged the intake manifold line with a pen and zip tie for now, extended the vent line(with appropriate fuel line and barb) across and over to the left side of the mp3. Gave it a few rides and so far so good

IMG_20200625_135611213_HDR.jpg

Team Scooter Trash for Petfinder Foundation   vespa scooterwest scooter west Motorsport Scooters   Cool Ass scooter seat cover
Post Reply    Forum -> MP3 Discussion
[ Time: 0.1566s ][ Queries: 27 (0.0343s) ][ Debug on ]