spitting out the air box?

[Guest rrbasso]

Well this weak I started getting a hesatation and a big spit back throug the air box, I dont have a lot of ex with fuel injection but with my Carb bikes this usualy meains in take leak, same with fuel injection ? I have the Ti cans and race brain but I did just resently put on the FBF air box on, could this be bad ? maybe the race brain doesant adjust enough for the FBF air box ? Whate do you think ?

[v50man]

Well this weak I started getting a hesatation and a big spit back throug the air box, I dont have a lot of ex with fuel injection but with my Carb bikes this usualy meains in take leak, same with fuel injection ? I have the Ti cans and race brain but I did just resently put on the FBF air box on, could this be bad ? maybe the race brain doesant adjust enough for the FBF air box ?  Whate do you think ?

49599[/snapback]

 

I believe the FBF kit changes the entire character of the engine. The good news is, you don't NEED a PCIII to compensate. A qualified dealer can tune the stock computer.

 

All my carb bikes do this when running LEAN.

[Guest rrbasso]

This is very interisting I didnt know that you could Tune the computer ? I thought it was untouchable, I do think it is running Leen I will give a call to the one dealer I kind of trust around here, Thanks

[al_roethlisberger]

.....yeah, I think there's a short thread on "tuning the ECU, etc" out there somewhere

 

 

http://www.v11lemans.com/forums/index.php?...4152&hl=tuneboy

 

 

[jrt]

You can do some tweaking of the computer, but it's a lot easier (read: cheaper) to just fool it. Adjust the TPS a little higher and see if that fixes your problem.

J

[Guest rrbasso]

What do you meain TPS ? sorry I just dont know ? How do I go about this, like I said I have had a lot of Carb bikes but this is my first fuel injection ?

[jrt]

TPS = throttle position sensor

Basically, it's a potentiostat (a volume control) that tells the FI how far open the throttle is, so the FI can determine how much gas to squirt in. Setting the TPS is analagous to setting the volume on a stereo, but you measure voltage instead of decibels. The TPS itself is just a plate screwed to the top of one of the throttle bodies. It's on the R/H side, has 'Marelli' stamed on top and has three wires coming out of if.

FI tune-up procedures are scattered here and there:

For the Tonti frames see here. There are a few differences though- On spine frames, the TPS is on the R/H side.

Here's a thread that has lot's of info in it (too much maybe?). It's aimed to PCIII owners, but it's applicable to standard TPS adjustments.

Basically- measure voltage across two of the three wires (the outer wires, I think) with the bike on, but not running. You'll have to pull the rubber boot back to get to the connector and I use a small gauge copper wire to stuff into the connector without ever disconnecting it. It should read in the 5-575 mV range (make a note). Gently loosen the two top star bolts on the TPS and slowly twist it one way then the other- the 500 mV reading will change up and down. Rotate the TPS so it's about 10 mV higher than it was when you started, tighten the star nuts and take the bike for a ride. Since this is a rough dial-in, don't bother with disconnecting the linkage et. al. Also, if you have a twinmax or similar carb balancer, you can balance the TB's with the white knob between the two TBs (bike running, of course).

If you're not comfortable doing it yourself, any shop should be able to set it in a few minutes. Maybe watch them, so you can do it yourself later.

Hope that helps.

Jason

[dlaing]

I believe the FBF kit changes the entire character of the engine.  The good news is, you don't NEED a PCIII to compensate.  A qualified dealer can tune the stock computer.

49603[/snapback]

Most dealers can tune the stock ECU, but there are limitations on what they can do to tune it.

They can not map it unless they bought mapping software, and I do not know of one authorized Guzzi dealer who has the mapping software.

Simply tuning the ECU, rather than mapping is good for changing the mixture with a broad paint brush at idle with an effect tapering off into the lower RPMs.

Tweaking the TPS is usually used to trick the bike to run richer in the lower and mid throttle ranges.

Once you get above about 80% throttle, there is no effect of the TPS tweak, nor the ECU 'tuning' on the mixture.

If you are adding freeer flowing mods such as the FBF airbox kit or louder pipes, chances are the greatest leaning in mixture is going to be at high RPMs and Throttle positions, where you can do little to tune it.

I suppose you or a qualified dealer could boost the fuel pressure for the most even broad sweep of enrichment.

But if you look at almost any PCIII map you will see that the stock map is both too rich and too lean for just about any modification.

Also, beware that if your dealer tunes the ECU to run better with your mods, and you subsequently try to go to a PCIII, you should have the dealer bring the ECU and TPS back to Guzzi recommended specs.

This is essential if you wish to use a map that was generated on another bike.