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Cali 1100i Misfire - again

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Bodmin Beast View Drop Down
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    Posted: 05 Jan 2019 at 09:22
A year ago I was posting up on here - http://www.guzziriders.org/1994-cali-1100i-misfire_topic8309_post79158.html?KW=1100i+misfire#79158 - asking for advice on a misfire issue I had. That seems to have been resolved after changing all relays, fuses, cleaning up every electrical connection I could find etc; until now.

New Year's Day I took it out after a 4 week lay-up, starting perfectly, running perfectly, until after 15 miles it started to mis-fire. Here we go again I thought; kept it running, turned round and headed for home. It soon became apparent the symptoms were very different from before, so I suspect a different cause.

The misfire is at low revs, particularly on a constant throttle. Riding through villages for example it was at it's worst. Back on the open road, gave it some throttle and it cleared, accelerating and running normally. Changing gear caused a hesitation, requiring more throttle than normal to clear the misfire. It will not tick over, but starts fine, albeit with extra throttle. 

Got home, changed the plugs, which were black and sooty, as though it was on choke. Checked the action of the choke cable, seemed ok. Left it overnight to see what happens on a cold engine, same thing.

Any ideas? Previously it mis-fired badly throughout the rev range, even assuming it would start. Now it is only at low revs and constant throttle, and will start.....?

Thanks

Ian
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Brian UK Quote  Post ReplyReply Direct Link To This Post Posted: 05 Jan 2019 at 10:23
Well the black and sooty plugs must be a clue. Somehow too much fuel is getting in.

A dripping injector could cause that, but both would have to be bad.

But worth running a high dose of injector cleaner through the tank.

Equally if the ECU thinks the engine is much colder that it really is, it would be injecting too much fuel. But I would expect that to be through the range.
Brian.

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Post Options Post Options   Thanks (0) Thanks(0)   Quote Bodmin Beast Quote  Post ReplyReply Direct Link To This Post Posted: 05 Jan 2019 at 11:36
Yes, it is something common to both cylinders. I have planned to give it a good dose of injector cleaner, just for good housekeeping. Wishing thinking that it may fix it!

I wondered if a temperature sensor was playing up, as you say. I was puzzled in that case as to why it cleared under load, and over 2000 rpm'ish. However, if it was a temperature sensor, why would it be displaying the same symptoms the following morning, cold engine and fresh plugs?

If it was a carb set-up I would be looking for a restriction in the pilot jet system. As it is fuel injected.....?

Bear in mind this is a 1994 model, so I don't know how sophisticated the electronics are. It has a manual, cable-operated choke.


Edited by Bodmin Beast - 05 Jan 2019 at 11:55
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Hbhonda Quote  Post ReplyReply Direct Link To This Post Posted: 05 Jan 2019 at 12:31
might be wild goose chase but had a similar problem with the Cali barnfind, managed to get mel Robinson to look at it . He reset the tappits but the main problem was the cold start mechanism on the top of the throttle bodies was not shutting off properly when the lever was shut back, 4 days of penetrating oil did the trick worth a try
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Bodmin Beast Quote  Post ReplyReply Direct Link To This Post Posted: 05 Jan 2019 at 14:07
Hi HB. Thanks for the input. First thing I did was to check the action of the choke cable, and it seems to be shutting off ok. As it has been in fairly regular use, I doubt it has developed the same fault on each throttle body. My thought was perhaps the cable was snagging up, which would affect both. If that was the issue, it should start and run ok from cold, one would have thought, but the misfire is there straight from cold start-up. 

I gave it a major service early this year, including checking the tappets. All well there.

Ian
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Hbhonda Quote  Post ReplyReply Direct Link To This Post Posted: 05 Jan 2019 at 14:25
next option might be to pull out the injectors get them cleaned and the spray pattern checked, both mine were replaced with second hand ones
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Bodmin Beast Quote  Post ReplyReply Direct Link To This Post Posted: 06 Jan 2019 at 13:25
Gents. Just to be clear, does the manual choke lever/cable arrangement simply open the throttle a little to prevent stalling when the engine is cold, while the ECU and temperature sensors adjust the fuel mixture? Can anyone pinpoint which is the air temperature sensor, please?

Thanks. Ian
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Post Options Post Options   Thanks (0) Thanks(0)   Quote s1120 Quote  Post ReplyReply Direct Link To This Post Posted: 06 Jan 2019 at 13:40
Dont have any experience with Guzzi's, but do with automotive FI systems. One questen for you..  The next morning when you started it up, did it skip right off the bat, or after it warmed a bit? If its right off the rip, at a cold start, it doesnt sound like the "choke" or temp sensor. Because it should be running rich at that point. If its after it warms a bit that it starts skipping, and you know the "choke" system is moving, I would look first at the temp sensor. Pretty common issue in the auto world. Its telling the ECM that its dead cold all the time, and pumping fuel in..  
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Brian UK Quote  Post ReplyReply Direct Link To This Post Posted: 06 Jan 2019 at 15:07
Can't tell you where the air temp sensor is, but it's item 49 on the diagram. The wiring colours might help to identify it.

However, I would expect the oil temp sensor to be the culprit (item 47). This, when indicating cold will tell the ECU to make the mixture rich as the engine is cold.

Conversely cold air is more dense, so a cold reading on the air temp sensor will weaken the mixture.
If either sensor is poorly connected, or not connected the ECU gets a clod reading. The resistance of the sensors reduces exponentially with heat.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Hbhonda Quote  Post ReplyReply Direct Link To This Post Posted: 06 Jan 2019 at 18:40
think the air temp sensor is behind the left hand side panel 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Bodmin Beast Quote  Post ReplyReply Direct Link To This Post Posted: 06 Jan 2019 at 19:54
Gents. Thanks for your input. Hi Paul. Good point, and I did not explain it clearly in my initial post. When I started it from cold; probably not as cold as where you areExclamation; it started missing immediately it started. That is counter-intuitive, which I am finding is a trait of Moto-GuConfusedzzis.

Brian, thanks for that. Trouble is I need to find it on the bike, and, despite having parts books, riders intsruction book, workshop manual, none seem to make things very clear! 

Thanks Hbhonda, I will see if I can trace it.

Meanwhile, I removed all relays and fuses (as I have done several times in the past!), sprayed everything with contact cleaner, worked them in and out of their positions a bit. Likewise the multi-connector on the ECU, although it looks very good; and about any other sensor or connector I could see. Then cleaned them off and sprayed them up with Dampstart. I had added a good dose of Redex injector cleaner to the fuel. It started right up, without choke, kept it running on the throttle, no probs.  Applied the choke to keep the revs up until it warmed, kept it running. Stopped it, got my gear on and took it for a 30 mile run in mixed conditions. It ran faultlessly. Back home, I checked the plugs; colour perfect.

So why I am I not a happy beast? Because this bike will not give up it's secrets easily. What was it which cured it? Is it cured? How can I trust it not to happen again? After the issues I had a year ago; see previous threads; same thing. I don't know what one single thing sorted it. Then, in August, 2 days before I was due to ride 500 miles to a rally in the Scottish Borders, the mis-fire returned. Just as before, with no apparent reason. I went through a similar process of checking and cleaning everything I could, but too late for the rally. It took a week of fiddling to get going, by which time the rally was over. Again, I don't know which one single thing got it running again.

It does not want me to trust it......

Cheers. Ian


Edited by Bodmin Beast - 06 Jan 2019 at 22:30
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Post Options Post Options   Thanks (0) Thanks(0)   Quote s1120 Quote  Post ReplyReply Direct Link To This Post Posted: 08 Jan 2019 at 13:26
When you cleaned the relays did you put them back in diferent places??  SOme of these years were known for bad ones, and you might have just moved them to diferent slots. Might want to get some new good ones, and replace them all. 
Paul B

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Post Options Post Options   Thanks (0) Thanks(0)   Quote c13pep Quote  Post ReplyReply Direct Link To This Post Posted: 08 Jan 2019 at 17:38
Originally posted by Bodmin Beast Bodmin Beast wrote:

Gents. Just to be clear, does the manual choke lever/cable arrangement simply open the throttle a little to prevent stalling when the engine is cold, while the ECU and temperature sensors adjust the fuel mixture? Can anyone pinpoint which is the air temperature sensor, please?

Thanks. Ian



Don`t know this engine but the cold start on fuel injection bikes is usually, as you say, with tickover speeded up to prevent stalling. My RT1150 is the same and has the temperature sensor in the middle of the air filter to monitor the induction air flow temperature. However failure of this sensor puts the ECU into a default setting to keep the engine running albeit `rough`, I do not know if Guzzis have this level of sophistication.

CHRIS
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Bodmin Beast Quote  Post ReplyReply Direct Link To This Post Posted: 08 Jan 2019 at 23:45
Hi Paul. Earlier in the year, when I had the other type of misfire problem (!) I installed all new relays and fuses, just for good housekeeping.

Chris, as Brian mentioned earlier, which I am sure is correct, it is the oil temperature sensor which richens the mixture when the engine is cold. However, it is working ok again now.....

Next time, I will have to clean one fuse at a time, one relay at a time, one connector at a time etc etc, trying it each time to see if I can weedle out which is the culprit, if indeed there is just one culprit, and that is assuming the problem each time is simply caused by a dodgy connection. Moto Guzzi's are known to have such issues it seems, particularly if they are left standing for any length of time, or, as per a comment I read in another thread, if we are foolish enough to take them out in the rain!
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Brian UK Quote  Post ReplyReply Direct Link To This Post Posted: 09 Jan 2019 at 07:53
Since you fitted new relays and fuses, I doubt any of them are the problem. Yes it's just possible one new relay is a dud, but highly unlikely.

Certainly woth going round as many wiring connectors as you can, pull them apart, spray some contact cleaner and lubricant (Servisol or similar) into them and put back together. If they look bad when you pull them apart, spend a little time cleaning.

Brian.

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