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Backfireing Stelvio

sabre64

sabre64

Just got it firing!
Joined
Mar 1, 2013
Messages
16
Reaction score
5
Location
Turmero, Venezuela
Hello guys.
Last night I brought home a (new for me) used 2008 Stelvio with 19,000 Km. on it.
On my way home I noticed that the engine is backfiring when i go downhill, this morning I turned the bike on and it start very fast, but it won´t keep the idle unless I put on some gas, this happens only for a minute or so, untill the engine warms up.
The guy how sold the bike said that this was normal.
Any advise, since I´m new to Guzzis
 
Re: 1200s Problem Help needed please.

No, its not normal and shouldn't behave like that. Have it serviced and tuned and balance the throttle bodies and reset the TPS. Has anybody messed about with the throttle stop screw on the L H throttle body?

Pete
 
Re: 1200s Problem Help needed please.

pete roper said:
No, its not normal and shouldn't behave like that. Have it serviced and tuned and balance the throttle bodies and reset the TPS. Has anybody messed about with the throttle stop screw on the L H throttle body?

Pete
Click to expand...

Listen to Pete! This is absolutely not normal. You have some kind of fuel delivery issue.

Bruce
 
Thanks for the reply guys.
I checked the throttle body linkage and it seems that nobody has tampered with it. It still has a red paint mark in the likage itself. Everything else seems untouched.
I´ve been reading in this forum about a stepper motor that controls the air intake for cold starts. Could it be it?
I´ve read about ECU reprograming
Does anyone knows how to check it.
This bike was originally sold by a BMW motorcycle dealer in Caracas, Venezuela, that no longer sells them. They only sold a few of them for that year. No service so far from them.
I´ve been all my life a Honda owner, I currently have a 2005 Goldwing (for me and my wife) on long trips and a 2008 Varadero. Most of my friends have moved to bemers, I don´t like them.
I purchased the Stelvio to replace the Varadero, I wanted to step up to a drive shaft bike.
 
regarding backfiring a further ad: would not hurt to check all exhaust seals for leakage, especially on the opposite side of clear view…
 
Could be the stepper motor but you should check the TB syncing and TPS setting first. A vast majority of stepper motors don't have problems.

Here are two threads to read for tuning.
https://www.guzzitech.com/forum/196/9215.html

https://www.guzzitech.com/forum/196/3768.html

Most modern bikes run lean and this contributes to exhaust popping on decel. This may be what you are hearing and not actual back firing through the TBs. If symptoms are not alleviated with tuning the next thing to address is the ECU mapping. The map is not easily changed. There are some ECU foolers on the market, one type involves the O2 sensor and the other the air intake sensor. These are bandaids and do not fix all the fueling issues but provide improvement in the lower half of the throttle range. I have been using a Memjet (air temp fooler) and it has been satisfactory for me - bikes seem to differ. For fueling perfection or as it should be from the factory. Todd provides an ECU reflash, power commander and auto tune option. I would suggest this path after proper tuning. The early Stelvio had performance issues that were improved on in later versions. An updated map is probably available from the dealer. I had mine updated on the B11, didn't notice much difference but you should check. There were multiple revisions to the stelvio that improved performance besides mapping. Since you don't have a dealer near by then the VDSTS is the only way to read the map ID code, you'll need this VDSTS software to reset you TPS anyway.

Read the threads above and get started with the tune up and check back in with us. I use a electronic TB syncronizer made by Carbmate instead of the fluid type, much more convenient - no hassle and I have not had an accuracy issue.

Good luck
 
Check your sparkplug cables. They can be a problem. They like to develop breaks, apparently where the wire screws into the boot piece.
 
...Can't add to the previous info except to say that I too, installed a mem-jet when I first got my 09.... works fine for me...although I eventually will send to Todd for a re-flash.....I'm probanly down several horsepower on a crisply -tuned unit.....which I don't mind....it's still quick and strong....good luck
 
Thanks once again to everyone for the replies.

I had a chance to drive it on a 260 km on sunday.
The bike is not actually backfireing on decel, but poping, I guess it´s normal for a twin engine.

I spoke today with the dealer who sold the bike (BMW dealer), they says that they have the instrument to check it.
I guess some tune up would not hurt anyone but my wallet.
With 19000 km I guess is about time, since the previus owner just did oil and filter change.

Diedel you´re right, I had a 2002 Honda shadow that pop more than usual and it was the header seal that was damaged, after they replaced it, everything came to normal. I´ll have that checked

Other wise I can say that the bike is agressive (love it) after 6000 rpm it runs like silk.
I´ll keep everyone informed as soon I get a chance to take it to the dealer
 
I hope you can get it sorted out, Sabre. These Stelvios are the sweetest running bikes on the road (and off!) when they are properly fettled. Please keep the forum posted on how you make out.
Cheers,
Bruce
 
If that 'backfiring' is actually a mild 'put-put' on decel it's not unusual. Mine does that too and I'm not worried. When you say "backfire" I think a loud BANG coming from the intake, and that is really bad. A mild pop from the exhaust on decel could be an air leak in the exhaust or just the very lean burn of the air/fuel mix. There is a huge difference and it comes down to how we use the language.
 
pyoungbl said:
If that 'backfiring' is actually a mild 'put-put' on decel it's not unusual. Mine does that too and I'm not worried. When you say "backfire" I think a loud BANG coming from the intake, and that is really bad. A mild pop from the exhaust on decel could be an air leak in the exhaust or just the very lean burn of the air/fuel mix. There is a huge difference and it comes down to how we use the language.
Click to expand...

And my decel popping was virtually eliminated when I installed Todd's 02 optimizer.

Bruce
 
pyoungbl said:
If that 'backfiring' is actually a mild 'put-put' on decel it's not unusual. Mine does that too and I'm not worried. When you say "backfire" I think a loud BANG coming from the intake, and that is really bad. A mild pop from the exhaust on decel could be an air leak in the exhaust or just the very lean burn of the air/fuel mix. There is a huge difference and it comes down to how we use the language.
Click to expand...


DITTO
 
Mine crackles like crazy on deceleration but I love it. It also alerts pedestrians! I've had a Quill exhaust since about 15k ago (which also eliminated the torque dip, but that's another thread) and revel in the rich, fruity sound of the Guzzi twin unleashed. If I wanted a quiet bike, I'd ride something else. Like a Honda. :D
 
Ok guys, yesterday came the tech guy from BMW, calibrated the valve clearance (clearance was ok), replaced the spark plugs, and the bike holds the idle when the engine is cold :D
He told me that those plug caps are a piece of crap. I ordered a pair of NGK plug caps, just in case.
It was very annoying to start the bike and putting some gas for the first 20 to 30 seconds in order to maintain the engine running.
Happy Guzzi owner
 
BravoBravo said:
And my decel popping was virtually eliminated when I installed Todd's 02 optimizer.

Bruce
Click to expand...

Link please? I searched and found more than I could handle. :lol: I have the Mistrial exhaust on mine , and while it does not really bother me it does after-fire quite a bit on deceleration. I hate to mess with an almost new bike but want to learn more.

Marc
 
lomax said:
BravoBravo said:
And my decel popping was virtually eliminated when I installed Todd's 02 optimizer.

Bruce
Click to expand...

Link please? I searched and found more than I could handle. :lol: I have the Mistrial exhaust on mine , and while it does not really bother me it does after-fire quite a bit on deceleration. I hate to mess with an almost new bike but want to learn more.

Marc
Click to expand...

Marc, Todd no longer sells the O2 optimizer as a stand-alone unit. It is now part of a fueling package:

viewtopic.php?f=235&t=5950

Bruce
 
I can't keep up with these threads, so always feel free to reach out to me direct email please.

That said, I spent a few hours at Dynojet yesterday, and the twin 02-sensor bikes are still unresolved. They are working on a software driven box to control the 02-sensors via the Power Commander V. They acknowledged that two 02-optimizers will certainly work, but it is not cost effective for them. I can offer a handful of twin 02-optimizer PC-V's for anyone interested for $524.95, or my ECU re-flash service is $500. Please contact me direct email to order, or I'll try to get them on the Store today or tomorrow.

Other 02 sensor offset foolers do NOT work (i.e. FatDuc), and have proven detrimental to fueling/engine life, as they are not capable of doing what's advertised on the newer ECUs (5AM & 7SM - Most ALL big block Guzzi). FACT: They go horrendously rich after one simple transition from closed to open loop and back.
 
I sent you an Email Todd. I have a 2012 Stelvio. I hope I don't miss this as I will not be able to order until tonight when I get home.

Thanks.

Marc
 
Guys

Sorry to pick up on an old thread but my Stelvio is doing exactly the same as Sabre64 described. I wen't hunting for the links in Rafaels reply to have a tweak with the tuning but they are dead links - any ideas

Rafael said:
Could be the stepper motor but you should check the TB syncing and TPS setting first. A vast majority of stepper motors don't have problems.

Here are two threads to read for tuning.
https://www.guzzitech.com/forum/196/9215.html

https://www.guzzitech.com/forum/196/3768.html
Click to expand...
 
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