2004 Breva 750-rough running sorted, now EFI light weirdness

[Mal]

Hi Guzzitech’ers

We brought a 2004 Breva 750ie for my partner (goes with the 1200 Sport in my avatar ) a week before a trip from Townsville to Agnes Water. We rode down over 2 days along the coast ~900km spent 2 weeks there and rode home inland also over 2 days ~1,100km.

The bikes performed really well but now when riding in town at 60~80km/h the 750 Breva seems to run a bit rough on constant throttle. Now she is new for us so it’s hard to notice a “change” as such but the rough running / surging is definitely noticeable but not unrideable. No surging was apparent while riding around on the week before the trip or during the 2 weeks while in Agnes Water. Also seems smooth at 100km/h just surging / rough in the 60 and 80km/h zones.

Possibilities

On the last day of the trip back we had to fill from reserve with normal unleaded (91 RON?) petrol, only fuel available for 200km. Also had to use premium unleaded (95 RON) during the trip when we couldn’t obtain my preferred BP Ultimate (98 RON - My Sport seems to ping under load when not on the 98 RON fuel)

The ride back was usually sustained ~120km/h and up to 30 deg C (not really that hot for North Queensland)

She did stop once when idling on the side of the road and took a few spins to start, also needed a bit of throttle and a few spins when cold to start on the last day. Not really issues but perhaps worth mentioning.

I’m thinking bad fuel, or perhaps some water in the fuel. My Sport is running fine but has a bigger tank than the Breva so I didn’t totally fill her tank except when I could get the 98 RON fuel. I was going to run the Breva to almost empty and then refill, but my partner just filled her when the reserve light came on (5 litres remaining)

There was some black specks when looking in the tank with a light, could be some “junk” in there that might have got shook loose on the rough roads.

The bike did sit in the Honda shop for sale for many many months (we got a good price) and the engine oil didn’t look real healthy when I changed it for the trip (It was at 27,000km so probably getting close to needing a service) Didn’t look at clutch and gearbox oil but I note the instruction manual has 80W90 handwritten for both of these. It was probably serviced at the local Honda shop, which sold Guzzi for a few years. They put the wrong viscosity engine oil in my sport, she was their last Guzzi demo bike, so they probably just used 80W90 as “close enough”. Guzzitech recommends the 85W-140 as important in the small block Guzzi rear transmission. I’m not mechanical myself so I’m not sure how important that is.

Really remote possibilities

Clutch on the Breva seems noisy when pulled in and idling stationary, but bike is really too new to be sure if that sound changed at all.

Spark plug caps very slightly loose but wiggling them while riding doesn’t make any difference so unlikely.

Also has a powercomander installed (unlikely to have “changed” unless there are buttons on it the could have rattled I’m not familiar with power comanders)

So after that loooooooong post any recommendations?

Thinking run a tank of fuel injection cleaner? If no luck I do have a good mechanic that looks after my Sport and the Breva will have to go for a service soon so get him to replace fuel filters etc. I can also look at downloading a powercomander map.

Thanks in advance.

 

[GrahamNZ]

Re: 2004 Breva 750 Running rough on constant throttle

Why not start by just fitting new spark plugs?

 

[Holt]

Re: 2004 Breva 750 Running rough on constant throttle

MAny questions. I've got a short mind, so bare.. :mrgreen:

The Breva seems to be very sensitive to wrong plug gap. Keep it at 0,65 mm to my experience.
I've always been running 95 octane without issues. That's about the only quality you can get here.
My Breva runs rough at 4000 rpms. There's an "unsweet spot" there, but where that spot is seems to vary between SBs.
Guzzi recommends a 85W/140 synthetic HYPOID GL 5 oil for the rear transmission. Guess the bevel gear is quite stressed, so go for the right stuff. A 1-liter bottle will be fine for the next 45000 kilometers, so price should not be an issue.
Clutch sounds normal. Rattling and noisy when pulled, silent when engaged and in gear.
It can be slightly unvilling to start after a long and hot ride. Dunno why, but eventually it WILL start. If the ECU-fuse isn't blown, that is. :whistle:
I have absolutely no experience of PCs.

At the bottom line; are throttles balanced and TPS set at any service? If you have a single-unit VDSTS for the Sport, it cannot be used for the Breva, which has a M15RC ECU.

 

[Mike.C]

Re: 2004 Breva 750 Running rough on constant throttle

Your problem is not unique, and Graham IMHO is on the money - look for the simple thing first! As they say "here is our story", at christmas we had the exact same problem on Sal's Nevada (same engine as your Breva) and here is what we found. First a general comment from the last three years riding it. The 750 definitely does not like 91 fuel, 95 seems OK but it seems much happier on 98.

So what happened, we ended up in Windsor west of Sydney on a 36 degree day and her bike was running like a cow, wouldn't idle, and rough running just as you describe. To be honest I don't think the heat had much to do with it, but was just the straw that broke the camels back.

I am a bush mechanic so back to basics, fuel/air/compression/spark. As luck would have it I started with the easy one and pulled a plug. Bloody hell, more carbon than a coal mine! cleaned em up and went looking for a cause. Carbon means rich mixture, mixture controlled by ECU and PCIII, easy! Pulled the PCIII off and bike went perfectly ever since.

I came back and had another look at the PCIII map and it is in some areas adding a bucket load of fuel, so there is no doubt that the map that is supplied for the 750 with the PCIII is the culprit, despite what all the dynos and fancy readouts will tell you a plug full of carbon does not lie and almost always means a mixture richer than optimal.

May I suggest as a 1st, pull the PCIII plugs out and return the bike to original OEM fuelling map without PC "adjustments". There is a big one connected in series with teh OEM harness at the back of the ECU on the RHS of the bike, then remove the plug from the little black box connected to the O2 sensor probably mounted somewhere near the starter motor and reconnect the O2 sensor to the OEM wiring harness, hopefully the installer left the OEM O2 plug tucked away for just such an occasion and didn't cut it off. This is literaly a 20 minute job and before you run it to see, check or renew the plugs.

If you need help call me... 0419 170 987

 

[russ in pa]

Re: 2004 Breva 750 Running rough on constant throttle

A year after I had the power commander installed on my bike I developed a rough running point or surging just under 4,000 rpm. Had it remapped, it ran better but came back a day or so later. Dropped off at the dealer they could not duplicate the problem. My surging issue would start after running about 15 minutes. It ran fine until then. I noticed it would go away after a WOT run in fourth gear. The next time I rode it came back so I did the same thing, full throttle in fourth until I nearly hit the redline. Did this a total of three times and the problem never came back. Since I use it for commuting to work the route was the same and so it made it convenient to do. That was four years ago. Talked to the dealer and they said maybe the ECU needed some sort of reset, and since the dealer ran full throttle on the dyno it was most likely the reason they did not see it. I also had the O2 emulator go bad and the symptom was after about 15 min of running the EFI would come on although the bike ran just fine. Modifications to the bike at the time was FBF slip-ons & the Pwr commander.

 

[Mal]

Re: 2004 Breva 750 Running rough on constant throttle

Thanks everyone, great info, sorry for the short reply but I just wanted to say thank you

We will pull the plugs tomorrow and toss in some new ones. Cheap and easy to do. Depending on what they look like we will take it from there.

The other 1/2 seems keen to have a go at the plugs. My Guzzi has certainly made me feel more like doing maintenance myself and learning some mechanical bits and pieces (Changed my 1st rocker cover gasket before our holiday, it was fun) Perhaps she will end up the same. Something about the design of the Guzzi just inspires you to have a go... perhaps because it just gives you more time to appreciate the look of the bike

 

[Mal]

Re: 2004 Breva 750 Running rough on constant throttle

New plug after 50 km mostly @ 80~100km/h

 

[sign216]

Re: 2004 Breva 750 Running rough on constant throttle

Pretty rich, eh? Mike and Russ have the right idea. Take off the Power Commander (PC) and reinstall the lambda sensor (oxygen sensor). The sensor will let the ECU (computer) automatically adjust the engine's mixture. But, before you take off the PC, check to see that the oxygen sensor is still there. If it's not, then you might want to stick with the PC and save money.

The sensor goes into the exhaust crossover, and the electrical connection is a plug behind the starter on the left side of the bike. You have to take off the starter and solenoid to get to the plug, but the starter/solenoid come off as one unit. It's not hard. The bolts and electrical connections for the starter are straightforward, but disconnect the battery as a first step or there will be sparks.

Hopefully the PC installer left the oxygen sensor still there. If the sensor isn't there any longer it might cost you, they can be a couple of hundred dollars I think. Don't get a used one, as they have a limited life. If the sensor is gone, then maybe have someone adjust the PC to a leaner mixture, and then you don't have to buy a new sensor. Some would argue that adjusting the PC is the better route anyway, but that's a separate debate.

Let us know how it works out,
Joe

 

[Holt]

Re: 2004 Breva 750 Running rough on constant throttle

Pretty rich, eh? Mike and Russ have the right idea. Take off the Power Commander (PC) and reinstall the lambda sensor (oxygen sensor). The sensor will let the ECU (computer) automatically adjust the engine's mixture. But, before you take off the PC, check to see that the oxygen sensor is still there. If it's not, then you might want to stick with the PC and save money.

The sensor goes into the exhaust crossover, and the electrical connection is a plug behind the starter on the left side of the bike. You have to take off the starter and solenoid to get to the plug, but the starter/solenoid come off as one unit. It's not hard. The bolts and electrical connections for the starter are straightforward, but disconnect the battery as a first step or there will be sparks.

Hopefully the PC installer left the oxygen sensor still there. If the sensor isn't there any longer it might cost you, they can be a couple of hundred dollars I think. Don't get a used one, as they have a limited life. If the sensor is gone, then maybe have someone adjust the PC to a leaner mixture, and then you don't have to buy a new sensor. Some would argue that adjusting the PC is the better route anyway, but that's a separate debate.

Let us know how it works out,
Joe

The plug to look for:

If the Lambda-sensor is gone, you may be able to find a non-OEM sensor that will fit. You'll need a 4-wire non-titanium type.

 

[Mal]

Re: 2004 Breva 750 Running rough on constant throttle

Thanks guys,

I've seen the lead from the lamda sensor on the exhaust, that lead it's just hanging loose. Not plugged into anything.

The bike did run fine before the trip, could the plug have shook apart on a rough road? If I read correctly the PowerComander doesnt use input from the sensor so it would have been just hanging in the breeze, like it is now.

I'll have another look to see if there is anything that lead can plug into.

And does the powercomander just "unplug" i.e. wherever it's connected into the wiring harness just unplug the connection and leave them open?

 

[Mal]

Re: 2004 Breva 750 Running rough on constant throttle

O.k Pics are a bit tricky as it's night and a lot of tangled wires :lol:

Lambda sensor lead, swinging in the breeze ( actually tied quite tidy with a cable tie)

This above plug, rather than going to the lambda sensor plugs into a little black box. When the bike is idling a little green light flickers on it. I'm guessing it is the little black box refered to here

the plug from the little black box connected to the O2 sensor probably mounted somewhere near the starter motor and reconnect the O2 sensor to the OEM wiring harness

The lead from the PC goes towards ECU on right hand side eventually going under some insulating tape, doesn't look like there is a "pulg" to unplug easly as recommended here

pull the PCIII plugs out and return the bike to original OEM fuelling map without PC "adjustments". There is a big one connected in series with teh OEM harness at the back of the ECU on the RHS of the bike

So should it be connected like it is on our bike, little black box connected into the OEM wirking harness, I guess so as if it was wrong the plugs wouldn't mate together.
(edit checked PCIIIUSB instalation instructions on the net it's installed correctly, the "insulating tape" is the PC lead. The OEM plug is hidden behind the ECU, I could disconnect and reconnect to stock)

Sooooo

The bike was running fine 2 weeks ago in the few days we had it, and when we test rode it before. Did the long highway trip cause this problem, or was it an "issue" always there, that only showed after the longer runs plus using lower octane fuels. Perhaps explaining why the bike was in for sale?

I'm not real mechanical and I'm not too keen on unpluging a heap of connections. I was traumatized with car wiring harnesses as a child with all their unused connections and plugs. My Dad would tell me "don't unplug or plug anything!" I'm 36 now and it's still a bit scary :unsure: But with a completely stock bike the OEM setup with the lambda sensor should run fine. No real advantage to the PC, unless you have aftermarket exhaust and filters, yes?

But I love computers and fiddling with them, I have downloaded the 722-001.djm Completely Stock Bike map. How to upload it into the PCIII and see if that changes how she runs. (I have a usb cable that would fit and a laptop, but no software and the bits I have looked at on the net talk about using software to upload the file)

 

[Mal]

Re: 2004 Breva 750 Running rough on constant throttle

Go software and uploaded map with laptop. Easy but existing map looked the same 2004 stock. Will go for a midnight ride an see how she feels, wish me luck

 

[NOLAGuzzi]

Re: 2004 Breva 750 Running rough on constant throttle

The plug on the bottom goes into the back of the ecu and the wiring harness plugs into the connection at the top. If you undo the top one first you will note that there a a little tab that needs to be depressed to get it apart. That is on the bottom side of the other plug going into the back of the ECU. Squeeze it correctly and it will disconnect. Then just plug the OEM connector into the ecu. No real way to do any harm unless you get really ham-handed with the ecu.

 

[Mal]

Re: 2004 Breva 750 Running rough on constant throttle

Fixed her Nothing like a nice night ride (2:45 am now)

Ran up the local hill ~15km with the newly downloaded map, no change. Was definitely not fun coming back downhill Came home and loaded the zero map (basically open loop fuel injection with no changes from the PC) and tried again, return of the beautiful bike She really is so enjoyable to ride. Took my 1200 Sport up the same hill after and she actually felt a bit strange in comparison, at least for a little bit, just such a nice, relaxed, enjoyable feel to the 750. I will be borrowing her quite often I think. Still has that normal fuel injection roughness on slight trailing throttle but basically perfect.

Strange how she was running o.k. then started missing, seems like what has happened to others happened to me too.

I will try to overcome my wiring harness phobia and have a go at disconnecting the PC and returning to OEM to see how that feels. Might be able to sell the PC or just keep it incase we get aftermarket pipes or something.

Thanks again everyone, we were just starting to worry about what was going on. My partner said "I though geting a 2nd hand one would mean all these issues have been sorted (I've been having "intresting times" with my Sport less than 12 mts old) but I think it revenge for saying mine was "less reliable than a Ducati!"

Thanks again for all the assistance everyone, really appreciated.

_/\_

 

[Mike.C]

Re: 2004 Breva 750 Running rough on constant throttle

Excellent result! A couple of comments.

- If you have put a zero map into the PCIII you are not completely back to stock, because at lower RPM's the ECU uses the O2 sensor to adjust the mixture, but of course you don't have teh O2 sensor connected in the system. The little black box with the LED on it fools the ECU into thinking that the O2 sensor is still connected.

- Your experience is identical to ours, the problem is the map for the 750 that is supplied with the PCIII not the PCIII itself, the map is just not correct for a bike used for travel, if ultimate power is the aim then I suspect that teh map might be on the money, problem is that ultimate power and reliability mostly don't go together. The other solution is to take the bike to a dyno tuning place and have them generate a better map. This is what we are going to do when time permits.

 

[Mal]

Re: 2004 Breva 750 Running rough on constant throttle

- If you have put a zero map into the PCIII you are not completely back to stock, because at lower RPM's the ECU uses the O2 sensor to adjust the mixture, but of course you don't have teh O2 sensor connected in the system.

Yes, so it's just like an open loop system now, running on on the ECU injection map without input from outside sensors. Does the lambda sensor "do" anything useful, i.e. save fuel, give better performance.... or is it just an emission control measure. i.e is there a benefit to trying to reconnect it?

the map is just not correct for a bike used for travel

Seems to be so. Performance wise, she may have accelerated a touch faster with the PC map. It's easy enough to play with the setting on the laptop, I could even run around town and touring maps just for fun. Much easier for me than having to try and do something mechanical and since my mechanic doesn't have computers or play with fuel injection stuff (he is old school)

Important to be able to do the electronic stuff myself. Must get around to getting some engine diagnostic software too that Vehicle Diagnostic Scan Tool looks SUPER useful, I wonder if you can get one that will do a 750 and 1200sport. The Centurion Pro is perhaps out of my budget, heck we got another bike 3 weeks ago so EVERYTHING is out of my budget Perhaps I should say it's an investment as I would not mind another Guzzi or Ducati in about 10 years time


But could the unleaded and premium unleaded fuel have been the cause? Most people do run the 98 RON fuels in bikes here. I hope it wasn't the fuel, we are worried because we have to go back inland to Emerald in a few weeks and she might even be riding solo. Charters Towers has 98RON then it's ~200km to Belyando only unleaded 91RON ~200km to Clermont only premium 95RON Before you get 98Ron in Emerald. What do others do. I guess we could test a tank of 91 just to see what happens.....

Speaking of fuel we ran out of fuel today..... at the top of mount Stewart. Was trying to run tank close to empty and she wouldn't pick up the last bit out of the tank when pointing downhill. Rolled for 7.5 km, clicking over 30,000km on the clock :lol: and starting, fortunately, for the only 3 uphill sections, but totally dry just as we reached the highway. Was the most "user friendly" empty tank ever didn't have to push at all. De just waited for me under a tree while I rode back into town, bringing 1.5l of fuel in a plastic water bottle to get her back to the servo, 5 min down the road.

Now we know our 750 holds 16.33L+(1.5L-5 min ride into town) around 53.5km of hill riding on reserve with 1/3 of reserve on the PC map and running rough.

 

[russ in pa]

Re: 2004 Breva 750 Running rough on constant throttle

The box (O2 emulator) with the LED fools the stock ECU by looking like the O2 sensor. The other part of this besides making it look like the sensor is there is it always the same. Basically for the PCIII to work the information coming out of the stock ECU must be consistent. I believe this is why mine developed the problem is that ECU had "learned" with the O2 sensor then when the PCIII was put on the signal coming from the O2 emulator was different. This is most likely why it happened the following year when I took the battery out over the winter. I believe when they installed the PCIII on my bike they did not reset the ECU by leaving the battery disconnected. Then when I did the 3 WOT runs it must of reset the ECU to the O2 emulator. The way the PCIII should be installed in my opinion is with a zero map and get the stock ECU running the same fuel curve with the O2 emulator. Once the system is stable then do a remap. The PCIII only "rescales" what comes out of the stock ECU, so if the ECU output moves around then when it is rescaled. The Lambda sensor basically allows the stock ECU to adjust over time to varying conditions or changes in the bike. The stock bike runs lean, the one thing to be careful of is if you run too rich there may be a risk of damaging the cats in the exhaust. Too much fuel can cause cats to overheat. Since I have changed my exhaust I don't run the risk.

 

[Mike.C]

Re: 2004 Breva 750 Running rough on constant throttle

Does the lambda sensor "do" anything useful, i.e. save fuel, give better performance.... or is it just an emission control measure. i.e is there a benefit to trying to reconnect it?

Yes absolutely, all of the above! Asside from the fact that it's a ten minute job (so why not do it?) MG put it in the system for a reason and if you are going to ditch the PCIII then there is no reason not to reconnect it.

However, you can also run the PCIII with it connected up as original ie without the black box with LED connected to the OEM wiring harness O2 plug and the O2 sensor connected instead as per orginal. All you need to do is keep zero adjustment settings in all the map cells below 40% throttle, then the ECU will be controlling the mixture on it's own using info from the O2 sensor in those areas and at throttle settings above that the PCIII will apply some adjustment.

But could the unleaded and premium unleaded fuel have been the cause?

Nope, octane rating (please help me here Pete!) AFAIK has nothing to do with it. Don't be too worried about 91, it won't hurt the engine for the odd tank or two. Lower octane would normally cause pinking or more correctly detonation heard as a rattle when the engine is under load, the Back'O'Burke "I need to get there" fix is simply to be gentle on the throttle till you can get some higher octane in the tank. The possibility of engine damage from low octane fuel in a low power tractor engine like the Breva 750 (and my Breva 1100 for that matter) is almost nill.

VDSTS: If you want to plug it into both your 1200 Sport and the 750 Breva you must have the Centurion version, BUT it is actually cheaper to buy 2 standard versions and if I had my time over that is what I would do. The Centurion version has more wires to connect because it uses a box of electronics between the pooter and the bike and more importantly uses a USB security dongle - loose it and she no work! Not only that, your computer must have 2 USB ports which my little $400 s'hand Laptop didn't so I have to use a USB hub to get the required ports to connect it all up - talk about spagheti wiring and makes pluggin it in a right royal PITA.

 

[Mal]

Re: 2004 Breva 750 Running rough on constant throttle

However, you can also run the PCIII with it connected up as original ie without the black box with LED connected to the OEM wiring harness O2 plug and the O2 sensor connected instead as per orginal. All you need to do is keep zero adjustment settings in all the map cells below 40% throttle, then the ECU will be controlling the mixture on it's own using info from the O2 sensor in those areas and at throttle settings above that the PCIII will apply some adjustment.

That sounds like something I would like to try. She did accelerate a bit better with the PC map, it's just the issue of fowling the plugs on long trips and the rough running on constant throttle (which I'm sure wasn't there before the long trip)

I might experiment with putting those map values back in at <90% throttle and just see how that feels. I'm guessing it's the ~50% throttle and 4,000 to 6,000 RPM range where the PC map issue was happening (Lots of increased fuel on the map there) so if I can get the injection settings basically "OEM" when steady at 80, 100 & 120 km/h we should not encounter the problem again I guess.

But I might have to wait a bit before I can extract the bike back from it's owner, she is really enjoying riding it now

Thanks for the VDSTS info too.

 

[Mal]

Re: 2004 Breva 750 Running rough on constant throttle

Since my sport is at the mechanics I had a chance to play with the Breva. I’ve reconnected the O2 sensor into the wiring harness, unplugging that little black box that the PC-III uses.

The PC-III itself is still in the circuit, although with a zero map. Normal riding performance seems about the same but I couldn’t get up and down the local hill to really check (they had it closed off for push bike racing)

But on the way home the red EFI light on the dash came on. I pulled over, stoped and wiggled where the O2 lead plugs into the wiring harness. I couldn’t get real good access to it originally to reconnect it so I though it may have come lose. The light went off after starting and I rode the rest of the way home.

But on the way to work today the red EFI light came back on again, perhaps after the same amount of run time too. Instead of pulling over I just stoped with the kill switch and started again at an intersection. But it wasn’t the standard start up; switch on; red EFI light illuminates; goes off; then start the bike. I was in a hurry so it was just switch her back on and hit start. The red EFI came on basically as the bike started running and stayed on for a bit after starting, normally just goes off once the bike is running.

Since I was basically almost at work, it didn’t come on again. But once at work I stoped and started normally and the light behaved normally.

None of this seemed to have any effect on how the engine was running Will see if the light goes on again on the way home and if it seems to take the same amount of time.