What controls the idle at start up?

[kwn306]

I have had an issue for the last couple of thousand miles and my dealer is stumped.........so is Mother Guzzi.

My bike starts right up when cold (sitting over night) and then dies, it refires without a problem but idles ruff and I have to give it little / slight throttle inputs for about one minute then it is fine. Once the bike is at normal operating temps it fires up and runs perfectly.

What I have done or what I know:

Plug boots have been replaced with NGK straight type
Charcoal canister and associated plumbing has been removed, TB's have allen cap screws installed to plug the ports
TPS has been reset and TB's have been synced
When shuting the bike down I can hear the stepper motor cycle and then its quite
Fuel mileage is much better than other people have been reporting for 2 up super slabbing (44 - 48 mpg US)
No error codes on speedo display
Problem is getting worse, it took three times to get the bike started this morning, OAT was 64 degs F.
I friggin LOVE this bike

What I don't know:

What is causing this condition
There appears to be a arrent vacuum hose not connected to anything near the rear of the fuel tank, under the battery box that is facing to the left side of the bike. I have no clue wear it goes, maybe a vent line from something ?!?!

HELP PLEASE from you long time Guzzists would be appreciated.

 

[bigtex]

Mine has been doing that for the last year. Probably closer to 20-30 seconds rather than a minute, but it sounds similar. If I just hit the starter and let it immediately idle, it will die. Once I give it some gas and get underway, it's happy.

This started last summer after the MGNOC national meet here in Colorado. The factory service guy tweaked a few things and uploaded the newest map. Running and mileage improved markedly, only downside was this starting issue.

Mildly annoying but nothing that I think about. If I had a daily commute, I would be more annoyed.

 

[FrostBittenCanadian]

Kurt: Mine has recently started to behave in this way. What has changed is... I adjusted a slightly loose exhaust valve clearance, balanced the TBs just about perfect a 3000 rpm and reset the TPS. What I found when I started this was... the adjuster screw for the TBs linkage had never moved from factory ( witness mark intact despite the fact it should have been done 3 times since new.) both air bleeds were open, r/h side was open 3turns approx, and l/h side was more. Bike always idled fine from cold, initially idle would be a little high and then after about 10 seconds it would drop down to a normal idle. I figured that was how it worked. Bike seemed to run fine. After I set it up, it will die sometimes when cold at startup. I restart it and if necessary give it a touch of throttle for a couple of seconds, then it warms up normally. After say 3- 5 mins. of running time ,it runs and idles SWEET! Once I had set it up I noticed a few things : engine revs freer,cooler, engine braking is no longer insane, snatchiness of throttling between 3-4000 rpm is almost vanished, and it Idles much better ( both airbleeds are closed as balance was bang on at idle). What I learned from all this you ask? I've read about them dying when cold, mine never did,now it does and I believe it's probably a characteristic of the mapping or whatever as the difference before and after is like night and day! Like getting a new bike. Also The guy who had dealt with it prior should try a lot F@#$%^& harder, the balance was out 5cm of hg at 3000 rpm. I also checked for induction leaks after having reconnected the charcoal canister lines from the inlet manifolds ( I think the cannisters days are numbered). Basically if I had to choose between the bike that never died when cold and the one I got now... easy choice. Oh yeah the mileage is greatly improved too.
For what it's worth FBC

 

[WayneOrwig]

Mine started this last year after the map change when the air temp is up. At cold outside air temps, say below 60F, it doesn't do it. At wrm air temps, I have to play with the throttle a touch for 10 - 15 seconds.

I tried to intentionally set the TPS too rich at idle. No change.
I tried to intentionally set the TPS lean at idle. No change.
So i don't think it is a mixture issue.

When I play with it next, I'll likely open both air screws and raise the idle speed.

 

[GTM®]

Mine started this last year after the map change when the air temp is up. At cold outside air temps, say below 60F, it doesn't do it. At wrm air temps, I have to play with the throttle a touch for 10 - 15 seconds.

Hmmm... the factory has timing revisions based on oil temp that adds a significant amount of advance up to 59F/15C then ~1 degree up to 68ºF/20C. Above 68º, there is none.

I hope to have my very own Big-S, finally, in a week or less.

 

[kwn306]

Mine started this last year after the map change when the air temp is up. At cold outside air temps, say below 60F, it doesn't do it. At wrm air temps, I have to play with the throttle a touch for 10 - 15 seconds.

Hmmm... the factory has timing revisions based on oil temp that adds a significant amount of advance up to 59F/15C then ~1 degree up to 68ºF/20C. Above 68º, there is none.

I hope to have my very own Big-S, finally, in a week or less.

Todd,

Can you hack the ECU to fix this problem? For a fellow that rides (commutes) everyday this is a PITA. It doesn't give you warm and fuzzies that its going to start each morning or afternoon when I leave work. Mine is beginning to back fire a little bit when attempting to give it little throttle inputs to keep it going. In typical Guzzi fashion, the tech rep is scratching his....... :whistle: :whistle: :whistle:

 

[GTM®]

Todd, Can you hack the ECU to fix this problem?

Not a problem, e-mail to follow.

 

[mattin]

Hi

My bike is Griso Quattro Valvole and it does exactly the same.
I saw with VDSTS that soon after a cold start the stepper motor run to maximum limit, that is 200, and yet the idle stayed too low, like 700rpm or so. Looked like the bike couldn't turn the idle air open enough.
So I opened the air screws two turns, and that helped. Practically settled the problem time being. Griso's default value is closed screws, only one opened a little if cylinder balance requires. Is that same for Stelvio? Or is Stelvio default different, like 3 turns open? This tuning was some months ago.
Now after half of minute or so the idle turns again a little down, though only visit just above 1000, but is perfect after some 3 to 5 minutes, closer to 1200 rpm.

I guess the opening of the air screws is not fixing the original cause, but seems to help.

I hope somebody finds the proper fix

There appears to be a arrent vacuum hose not connected to anything near the rear of the fuel tank, under the battery box that is facing to the left side of the bike. I have no clue wear it goes, maybe a vent line from something ?!?!

That must be a gear box breathing hose. In Griso it can be seen pretty well starting behind the battery and going down to gear box.

- Matti

 

[kwn306]

Hi

There appears to be a arrent vacuum hose not connected to anything near the rear of the fuel tank, under the battery box that is facing to the left side of the bike. I have no clue wear it goes, maybe a vent line from something ?!?!

That must be a gear box breathing hose. In Griso it can be seen pretty well starting behind the battery and going down to gear box.

- Matti

And why do we need to let the gear box / transmission breath?

That really isn't heathly on an Adventure bike that might or in my case will be going through streams that are deeper than the top of the gear case.

Synthetic gear box oil does not foam up, what was Luigi thinking?

 

[Brian UK]

Well on most of these models, the gearbox vent ends up about the same height as the engine air intake, so if you intend to go in that deep water, beware.

 

[kwn306]

Well on most of these models, the gearbox vent ends up about the same height as the engine air intake, so if you intend to go in that deep water, beware.

Brian, I took the air box apart back during the winter months and brought it inside, cleaned it real good and waterproofed it really well, wife was non to pleased because I used the kitchen table as a work bench :woohoo: I have had the TB's under water (10 days ago) with no water infiltration, so the HD water resistant grease I used on the TB throats worked really well. This errant vent line runs up from the bottom and then bends over and heads back south, it isn't tied up high.

Now that I know it goes to the gear box I will drain and check the gear lube for water tonight. I also found another vent / vacuum hose just laying around the shock last night, it had a brass fitting plugged in the end, I think it is supposed to be attached to the battery tray in case of spillage of acid. At least the brass fitting slid into the short little tit on the battery tray.

Now if I can get my VDST program to talk to the bike my day would be complete, I fooled with it for about an hour and a half last night while getting eaten alive by bugs. The fool thing keeps searching the com ports but never finds one it likes. I even had the wife over see what I was doing per the threads on this forum to make sure I wasn't missing anything, still nothing, will try again Thursday. :S :S

 

[GuzziMoto]

Hi

There appears to be a arrent vacuum hose not connected to anything near the rear of the fuel tank, under the battery box that is facing to the left side of the bike. I have no clue wear it goes, maybe a vent line from something ?!?!

That must be a gear box breathing hose. In Griso it can be seen pretty well starting behind the battery and going down to gear box.

- Matti

And why do we need to let the gear box / transmission breath?

That really isn't heathly on an Adventure bike that might or in my case will be going through streams that are deeper than the top of the gear case.
Synthetic gear box oil does not foam up, what was Luigi thinking?

Luigi was thinking (and rightfully so) that if he did not vent the gearbox as it got hot it would build up pressure inside which could cause fluid to be forced out through one of the seals causing a leak. Even the rear drive is vented, isn't it? Keep that in mind with your stream crossing shenanigans.