Hi I have a 2000 900sport ie and it started cutting out at about 6500rpm. the rev counter drops to zero then it fires up again, back of the throttle and it will run fine, hard to tell if its fuel or electrical, think its electrical as rev counter drops to zero. If you hold it at tnat revs it fires and cuts out. Like fuel starvation. Was running fine untill the cranksensor went faulty and was sitting for a couple of weeks till i got a new one. has done this before after stitting all winter, last time tried new fuel pump, fuel filter, plugs, air filter, cleaned fuel pressure reg and throttle bodies, checked wiring , injector cleaner, eventually thrashed the shit out of it hoping it would come alright or blow up. It came alright and ran great the rest of 2019. Ran great the in 2020 and this year up till now (didnt do many miles in 2020) Anyone have any ideas on a fix other than change gear earlier or thrash the shit out of it and hope.
I was going to say crank sensor but you've got a new one. If it doesn't know the RPM but everything else is still powered up it can't really be much else though, so it's probably crank sensor / vibration related, especially since it started after you changed it. I'd be looking at the sensor wiring to the ECU, especially the three pin connector it plugs into, on the left hand side of the engine. Mine stopped starting the other day and that connector was full of water. There are some sharp bends in that bit of the wiring too. Try running it with the side panel off and wiggling the wiring to see if it stops. Difficult with the daft sidestand I know. For reference it's a Tyco Junior Timer connector - there is a sealed version which you can buy off Ebay for three or four quid. I'll get round to changing it one day. Of course, just because the sensor is new doesn't mean it isn't broken, but it makes it much less likely. It's a Fiat part - you can buy one for very little money so it might be worth changing it again if all else fails - it can only really be tested by substitution. These are apparently the part numbers, from someone else's blog so I don't take any responsibility if they're wrong! Search Google for them and there are loads of options from not much more than a tenner: Fiat 46774532, 55187333, 7777960; Standard 18805, SEB414; Alfa Romeo 77872560; Magneti Marelli 4820171010; Lancia 77872560 I might be completely wrong though, but if the revcounter stops it's definitely electrical.
Thanks for reply, the problem didnt just start after the new crank, it just seems to have come back after being away for a while. the new crank sensor was for a fiat Bravo. I change the crank sensor because it had started to cut out after 10 miles and would not start till it cooled down again.(did it several times), was no spark at all. Yea I think it must be electrical. Do the throttle position switches give much problems?
Ah I see, that makes sense. No idea about the TPS, sorry. I'm a bit new to the i.e. - my last SS I had had a Weber carb and it was a very long time ago. More used to car injection systems really. I'm pretty sure a throttle position error wouldn't stop the revcounter working mind you but I might be wrong. The reason you changed the sensor is a classic crank sensor symptom though - I had an Alfa 156 which did exactly that and it was the sensor. Probably the same part even, or a very similar one. Are you sure everything else stays on when it cuts out? Like, does the headlight go out? If anything apart from the revcounter and the engine goes off then I'm barking up the wrong tree and it could be the ignition relay (or its socket) or something else in the power supply. My gut feeling is that it's unlikely to be directly related to the RPM or throttle position, but more likely to be indirectly related, i.e. via vibration. There doesn't seem to be much activity in this bit of the forum - might be worth asking in the technical help bit in case someone there has had the same issue. I'd still try wiggling the harness while it's running though - that made mine stop and it's how I found the dodgy connector. Of course it could be an ECU fault. Hopefully not.
the problem is it doesn't actual stop and only does it at 6500 TO 7000RPM so hard to do it with out riding the bike. Not brave enough to do it sitting still again. All though I have tried it once and could get it to do it, but don't think the neighbours were too happy the last time I did it ha ha even with standard exhausts. The everthing seemed to stay on like head lights etc. It is like a rev limiter cutting in. Just weird it went away and is now doing it again. Think I will try checking all the connection again, checked all the when I was stuck at the side of the road when the crank sensor was failing, when the crank sensor had cooled down it started and drove home great and i had been using it to work before most of the summer. Think i will try and get that connector you mentioned and change that too
What does the rev counter pick up on ? Is it the alternator? if you spin it over with the plugs out it doesn't read, only reads when it actually fires and is running
As far as I can tell from the wiring diagram it is connected directly to the ECU, so it gets a speed signal from there. That must ultimately be derived from the crank sensor; the alternator isn't connected to the ECU. I imagine the rev counter doesn't function during cranking.
thanks I will just have to wait to the new connector arrives and try that if it isn't that. must be wiring or faulty new crank sensor or ecu. Life was so much easier before electronics
could be the tps connector check for corrosion inside the connector mine had let water in down the wires as they were thin and seal in the connector once cleaned and sorted i put sillicone gasket sealer around wires that cure it also had an elusive miss fire eventually found to be the ignition switch internals at fault ie falling apart have heard of similar fault from the handle bar run/stop switch
thanks will check those connecters too Started stripping the bike down to try get to the bottom of the problem. what does the sensor do on the front cylinder head? Is it oil temp?
According to the manual it's the engine oil temperature sensor. Odd place to put it but it says: "The sensor (2) is positioned on the horizontal head valve cover and measures the temperature of the engine oil." The only sensor inputs it actually needs to run as far as I can tell are the crank sensor (which points at the gear on the half-time shaft I think so negates the need for a phase or cam sensor) and the throttle position sensor. The other sensors are air and oil temperature and air pressure which modify the mixture but won't stop it running. It's mapped so doesn't have a MAF (airflow) sensor like a Bosch car engine management system. It's pretty much the same as a Fiat Panda actually, but without the idle stepper motor, hence the manual cold start lever. Have you got the manual? I downloaded it from somewhere but can't remember where. I could have a look if you like.
I've had a look and as far as I can see there's no electronics in the fuel pressure regulation, it's just a mechanical regulator, so I think the answer is no, it doesn't know the pressure so can't react to it. I think that's right anyway - there's a good description of how it all works in the factory manual (p220 onwards), if that's the one you've got, and it doesn't mention a fuel pressure sensor.
Thanks It must be the same manual. I've now read that. Its hard to tell if the fault is electric related or fuel starvation. Its very hard to work out if the rev counter would still read if the fuel supply stopped and the engine was turning (ie. if it was in gear and doing about 50mph) I think I will try running it down a hill with the plugs out and in gear to see if the rev counter turns.
Thanks for everyones help The rev counter will read if the engine is turning and not firing, but doesn't when cranking. Appears I managed to purchase a faulty crank sensor Retrieved the old one from the bin, put it on bike runs great till the sensor gets too hot. Put the new one in the bike runs great till about 6500rpm (new sensor wasn't even from eurocartwats!!)
It would appear that not all crank sensor will work. The orginal crank sensor is a Bosch 0261 210 124 But a cargo sensor wont work correctly, neither does Intermotor sensor wbich are both supposed to be a cross reference to the Bosch number. On closer inspection the center of the Bosch sensor has exposed metal part, maybe this is the difference? They are listed to fit a fiat and fiats don't rev to 6500 to 7000 rpm. Can anyone recommend a make that works other than an overpriced Ducati or Bosch one ?
Will either of these do? https://www.ebay.co.uk/itm/174908632369?hash=item28b95ded31:g:96oAAOSwFA9hJmGR https://www.ebay.co.uk/itm/16508307...3D%3D|ampid:PL_CLK|clp:2047675&epid=249557024
Sorry, no ideas beyond the ones you will have had already - they all seem to be about £50 or more e.g. https://www.onlinecarparts.co.uk/bosch-1149617.htm - never used these people so not a recommendation. But that's interesting, and worth knowing, thanks. Is it a different length, or is it just that end? Shorter would explain it, even by a millimetre or two. I bet some of the non-Bosch ones are actually a Bosch part in different packaging, but it's knowing which ones, and which ones are Chinese copies.
