F4 750 runs way to rich - MVAgusta.net
Reply
 
LinkBack Thread Tools Display Modes
post #1 of 18 (permalink) Old 12-02-2016, 01:44 AM Thread Starter
New Member
 
Join Date: Nov 2016
Posts: 17
Unhappy F4 750 runs way to rich

Hi guys.

I have a 2001 MV F4 750 that I can't get to run right.
Whatever I do, I can't get it down in CO%. Actually it's usually around 9-10% CO

Ofcourse that means it won't idle properly and eventually will foul the plugs.

When I got the bike, it had a gear indicator and Powercommander fitted. I removed both in trying to fix the issue.

Furthermore I have fitted the standard EPROM since I know nothing about the one that was fitted.

Cleaned the tank and pump mesh, and fitted a new fuel filter.
New spark plugs.

I have the idle CO turned all the way towards lean. If I turn towards rich it will choke the engine on fuel.

Fuel pressure is about 3 bar all the time.

I have also tried to unplug the Air Temperature Sensor and the water temperature sensor fitted in the cylinder head. Neither has any effect.

TPS and throttle balancing has also been done.

I can start the engine and it will rev pretty decent but blow a lot of black fuel smoke. Appears that the revs wont climp higher than about 11-12.000 rpm.

Any good ideas?
LarsLaursen is offline  
Sponsored Links
Advertisement
 
post #2 of 18 (permalink) Old 12-02-2016, 02:13 AM
Senior Member
 
gotojoe's Avatar
 
Join Date: Nov 2009
Location: Bellanagare, West Ireland 44 7875 299281
Posts: 9,930
Check specification and service state of air filter.
Plug gaps and type.
Air pressure sensor plays a key role in the ecu determining both the duration and timing of the fuel injection.

Good luck !
Joe
gotojoe is offline  
post #3 of 18 (permalink) Old 12-02-2016, 02:41 AM Thread Starter
New Member
 
Join Date: Nov 2016
Posts: 17
NGK CR9EB - Stock gap.
Air box not mounted while I do the servicing, but air filter is new BMC.

Where is the air pressure sensor mounted?
LarsLaursen is offline  
Sponsored Links
Advertisement
 
post #4 of 18 (permalink) Old 12-02-2016, 04:56 AM
Senior Member
 
jimboF4's Avatar
 
Join Date: Sep 2007
Location: North Somerset, England
Posts: 1,511
Air pressure sensor in LHS air tube level with headstock, easily accessible with fairing off.

jimboF4

in the garage: 2001 F4 750 1+1, 2005 Brutale 910S Carbon, 2007 Brutale 910R, 2009 F41000R, 2013 Brutale 800, 2015 Turismo Veloce 800,1976 Triumph T140D Bonneville, 1976 Honda CB400F2.
jimboF4 is offline  
post #5 of 18 (permalink) Old 12-02-2016, 07:07 AM Thread Starter
New Member
 
Join Date: Nov 2016
Posts: 17
Okay thought that was the Air Temperature Sensor.
I've unplugged it and without any result... Bikes still running insanely rich.
LarsLaursen is offline  
post #6 of 18 (permalink) Old 12-02-2016, 08:39 AM
Senior Member
 
gotojoe's Avatar
 
Join Date: Nov 2009
Location: Bellanagare, West Ireland 44 7875 299281
Posts: 9,930
Quote:
Originally Posted by LarsLaursen View Post
Okay thought that was the Air Temperature Sensor.
I've unplugged it and without any result... Bikes still running insanely rich.

The sensor is dual ie air pressure and air temp.

Interestingly when air temp is low the temp thermistor resistance increases.

Then fuel injection duration is increased.

So, pulling the connector plug will cause full electrical open and your fuel injection duration will be at it's greatest ie richest ?

So in pulling the connector you aren't isolating the problem, ?



I have a feeling though that the fuel pressure regulator is at fault here ? I read you checked it though

Joe
gotojoe is offline  
post #7 of 18 (permalink) Old 12-02-2016, 09:50 AM Thread Starter
New Member
 
Join Date: Nov 2016
Posts: 17
The readout I get when checking the fuel pressure is a little bit unstable - I think that's mostly due to the fact that my gauge is leaking a little bit.
Anyway it pretty much holds 3-3.5 bar. Not super stable...

Okay I've gotten hold of the diagnostic software now and will see what that tells me (if I can get it to work )
LarsLaursen is offline  
post #8 of 18 (permalink) Old 12-06-2016, 04:23 AM
Senior Member
 
Matt M.'s Avatar
 
Join Date: Jan 2013
Location: Nj, USA
Posts: 465
[QUOTE=LarsLaursen;2159449]NGK CR9EB - Stock gap.
Air box not mounted while I do the servicing, but air filter is new BMC.

Where is the air pressure sensor mounted?[/QUOTE

Is the air filter over oiled?

"When the people fear their government there is tyranny,when the government fears the people there is liberty. My reading of history convinces me that most bad government results from too much government"--Thomas Jefferson
Matt M. is offline  
post #9 of 18 (permalink) Old 12-06-2016, 04:33 AM
sms
Established Member
 
sms's Avatar
 
Join Date: Feb 2013
Posts: 75
what rpm does it idle @

could be some one has adjusted the link in tb's, i couldnt get my 910 to run right when i first got it, sort of like a splutter @ idle, cleaned filter, changed ecu, tb sync, tps reset and so on could not get it to run, as if it was really rich, turn the main link facing the ecu 2 turns clock wise and see how that is!

Never Poke The Bear!
sms is offline  
post #10 of 18 (permalink) Old 12-06-2016, 04:35 AM Thread Starter
New Member
 
Join Date: Nov 2016
Posts: 17
No... And it's not mounted. I don't have the airbox on at the moment - doesn't change a thing if I have it on or not.

I can't get the diagnostic software to work on my laptop so I'm kinda stuck.

Is there a chance that there's a fault in the ECU making it run so rich?
I don't have access to a ECU i can borrow but i'm at the point where I would be willing to buy one and hope that cures the problem.
LarsLaursen is offline  
Reply

Quick Reply
Message:
Options

Register Now



In order to use all of the features of the MVAgusta.net site, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome