Over -fuelling

[Pete-S]

Been a member on here for years, but this is my first time posting a request.
My issues started about 2 years ago with the FI light coming on and no fast idle whilst I was at the Isle of Man T.T.
Once I got home, found the loose magnet in the STVA (C28 error ), not just loose, cracked in half.  So, bought 2nd hand throttle bodies, swapped the good armature into my STVA, all working as it should.  Couldn't get rid of the F.I light or the C28 error though, even though I checked and rechecked the TPS & STPS.  Bike ran absolutely fine, so wasn't too fussed.
Over this winter I decided that I was sick of seeing that F.I light, so I replaced the TPS & STPS, and calibrated as per manual, still no difference.  Bike was still running fine, fast idle worked as it should etc.
Couple of months ago, started having worse issues.  Once it's hot it won't tick over, every time I pull up to traffic lights or a roundabout etc. it stalls.  Bumbling along in traffic at low speed/revs it's a bitch, feels like it's flooding.  Whack the throttle open and it's fine.  So, definitely over fuelling (smells rich, black smoke etc).  Also, flat out, it won't pull past 6500rpm and 125mph, whereas before it would rev cleanly to 8000rpm and hit 150.  Checked the compression, well within spec  (150 psi on all four cylinders).  Sent the injectors off for cleaning & refurb (they were fine before cleaning according to the report ), Replaced the fuel pressure regulator, no change, just replaced the cam position sensor, no change.  I'm out of ideas now.  If I need to buy a new set of throttle bodies, I'm happy to (even though they are a fortune) but thought I'd post on here on the off chance anyone has any suggestions.
Unplugging the power commander has made no difference.  I would welcome any suggestions, and recommendations as to a good mechanic/bike shop/specialist where I can take it ( feel dirty all over, never had to take a bike in for repair in my life).
Located in Bradford, West Yorkshire ( UK )

Regards

Pete

[KiwiCol]

Hmmmm, sounds tricky.    Just as an 'out there' idea, have you thought about taking it to a dyno place?  Don't they adjust / check the fueling?   That could work & you get a mapped bike in the process.  You wouldn't even need to feel dirty as it's not a repair, it's getting dyno'd . . .

[Pete-S]

Hi there, thanks for responding.

It has been Dyno'd and mapped for the PCIII, and it runs the same with or without the PCIII plugged in.  But, yeah, I'll call in and have a word with them, they might be able to offer a solution, can't hurt, thanks.


Regards

Pete

[Hooli]

Check the oil temp sensor, that's the main way these engines control how rich they are. I've seen them go to very high resistance so the bike thinks it's in a freezer all the time. The figures are in the manual, but it's something like fifty Ohm at 15c & mine was over fifteen hundred Ohms..

Cutting out could be the vacuum pipes splitting. Or the PAIRS valve leaking, that's been seen occasionally. Also try another clutch switch as I've heard of the spring inside rotting so they randomly drop onto the starting maps which really ruin how the bike runs.

[Will14]

Been a member on here for years, but this is my first time posting a request.
My issues started about 2 years ago with the FI light coming on and no fast idle whilst I was at the Isle of Man T.T.
Once I got home, found the loose magnet in the STVA (C28 error ), not just loose, cracked in half.  So, bought 2nd hand throttle bodies, swapped the good armature into my STVA, all working as it should.  Couldn't get rid of the F.I light or the C28 error though, even though I checked and rechecked the TPS & STPS.  Bike ran absolutely fine, so wasn't too fussed.
Over this winter I decided that I was sick of seeing that F.I light, so I replaced the TPS & STPS, and calibrated as per manual, still no difference.  Bike was still running fine, fast idle worked as it should etc.
Couple of months ago, started having worse issues.  Once it's hot it won't tick over, every time I pull up to traffic lights or a roundabout etc. it stalls.  Bumbling along in traffic at low speed/revs it's a bitch, feels like it's flooding.  Whack the throttle open and it's fine.  So, definitely over fuelling (smells rich, black smoke etc).  Also, flat out, it won't pull past 6500rpm and 125mph, whereas before it would rev cleanly to 8000rpm and hit 150.  Checked the compression, well within spec  (150 psi on all four cylinders).  Sent the injectors off for cleaning & refurb (they were fine before cleaning according to the report ), Replaced the fuel pressure regulator, no change, just replaced the cam position sensor, no change.  I'm out of ideas now.  If I need to buy a new set of throttle bodies, I'm happy to (even though they are a fortune) but thought I'd post on here on the off chance anyone has any suggestions.
Unplugging the power commander has made no difference.  I would welcome any suggestions, and recommendations as to a good mechanic/bike shop/specialist where I can take it ( feel dirty all over, never had to take a bike in for repair in my life).
Located in Bradford, West Yorkshire ( UK )

Regards

Pete

Did you balance the throttle bodies after doing the work on them & have you had the spark plugs out, they may tell you if some of the cylinders are running richer or leaner than the others?

Cheers

Pete

[grog]

Clutch switch my first thought to check.

[Pete-S]

Check the oil temp sensor, that's the main way these engines control how rich they are. I've seen them go to very high resistance so the bike thinks it's in a freezer all the time. The figures are in the manual, but it's something like fifty Ohm at 15c & mine was over fifteen hundred Ohms..

Cutting out could be the vacuum pipes splitting. Or the PAIRS valve leaking, that's been seen occasionally. Also try another clutch switch as I've heard of the spring inside rotting so they randomly drop onto the starting maps which really ruin how the bike runs.

Hi, thanks for the response.  I'll check the oil temp switch (and replace the clutch switch for the little it costs), thanks.  Already replaced the vacuum pipes, and the main fuel hose (just in case it was sucking air in).  I blanked Pairs off a few years ago....    Regards, Pete

[Pete-S]

Been a member on here for years, but this is my first time posting a request.
My issues started about 2 years ago with the FI light coming on and no fast idle whilst I was at the Isle of Man T.T.
Once I got home, found the loose magnet in the STVA (C28 error ), not just loose, cracked in half.  So, bought 2nd hand throttle bodies, swapped the good armature into my STVA, all working as it should.  Couldn't get rid of the F.I light or the C28 error though, even though I checked and rechecked the TPS & STPS.  Bike ran absolutely fine, so wasn't too fussed.
Over this winter I decided that I was sick of seeing that F.I light, so I replaced the TPS & STPS, and calibrated as per manual, still no difference.  Bike was still running fine, fast idle worked as it should etc.
Couple of months ago, started having worse issues.  Once it's hot it won't tick over, every time I pull up to traffic lights or a roundabout etc. it stalls.  Bumbling along in traffic at low speed/revs it's a bitch, feels like it's flooding.  Whack the throttle open and it's fine.  So, definitely over fuelling (smells rich, black smoke etc).  Also, flat out, it won't pull past 6500rpm and 125mph, whereas before it would rev cleanly to 8000rpm and hit 150.  Checked the compression, well within spec  (150 psi on all four cylinders).  Sent the injectors off for cleaning & refurb (they were fine before cleaning according to the report ), Replaced the fuel pressure regulator, no change, just replaced the cam position sensor, no change.  I'm out of ideas now.  If I need to buy a new set of throttle bodies, I'm happy to (even though they are a fortune) but thought I'd post on here on the off chance anyone has any suggestions.
Unplugging the power commander has made no difference.  I would welcome any suggestions, and recommendations as to a good mechanic/bike shop/specialist where I can take it ( feel dirty all over, never had to take a bike in for repair in my life).
Located in Bradford, West Yorkshire ( UK )

Regards

Pete

Did you balance the throttle bodies after doing the work on them & have you had the spark plugs out, they may tell you if some of the cylinders are running richer or leaner than the others?

Cheers

Pete

Hi, thanks for responding.  Yep, balanced them again a few weeks ago, checked the plugs, nothing obvious unfortunately...

[Pete-S]

Been a member on here for years, but this is my first time posting a request.
My issues started about 2 years ago with the FI light coming on and no fast idle whilst I was at the Isle of Man T.T.
Once I got home, found the loose magnet in the STVA (C28 error ), not just loose, cracked in half.  So, bought 2nd hand throttle bodies, swapped the good armature into my STVA, all working as it should.  Couldn't get rid of the F.I light or the C28 error though, even though I checked and rechecked the TPS & STPS.  Bike ran absolutely fine, so wasn't too fussed.
Over this winter I decided that I was sick of seeing that F.I light, so I replaced the TPS & STPS, and calibrated as per manual, still no difference.  Bike was still running fine, fast idle worked as it should etc.
Couple of months ago, started having worse issues.  Once it's hot it won't tick over, every time I pull up to traffic lights or a roundabout etc. it stalls.  Bumbling along in traffic at low speed/revs it's a bitch, feels like it's flooding.  Whack the throttle open and it's fine.  So, definitely over fuelling (smells rich, black smoke etc).  Also, flat out, it won't pull past 6500rpm and 125mph, whereas before it would rev cleanly to 8000rpm and hit 150.  Checked the compression, well within spec  (150 psi on all four cylinders).  Sent the injectors off for cleaning & refurb (they were fine before cleaning according to the report ), Replaced the fuel pressure regulator, no change, just replaced the cam position sensor, no change.  I'm out of ideas now.  If I need to buy a new set of throttle bodies, I'm happy to (even though they are a fortune) but thought I'd post on here on the off chance anyone has any suggestions.
Unplugging the power commander has made no difference.  I would welcome any suggestions, and recommendations as to a good mechanic/bike shop/specialist where I can take it ( feel dirty all over, never had to take a bike in for repair in my life).
Located in Bradford, West Yorkshire ( UK )

Regards

Pete

Cheers

Pete
[Thanks for responding.  yep, balanced them quite recently, plugs aren't really telling me anything useful unfortunately]

[Hooli]

Check the oil temp sensor, that's the main way these engines control how rich they are. I've seen them go to very high resistance so the bike thinks it's in a freezer all the time. The figures are in the manual, but it's something like fifty Ohm at 15c & mine was over fifteen hundred Ohms..

Cutting out could be the vacuum pipes splitting. Or the PAIRS valve leaking, that's been seen occasionally. Also try another clutch switch as I've heard of the spring inside rotting so they randomly drop onto the starting maps which really ruin how the bike runs.

Hi, thanks for the response.  I'll check the oil temp switch (and replace the clutch switch for the little it costs), thanks.  Already replaced the vacuum pipes, and the main fuel hose (just in case it was sucking air in).  I blanked Pairs off a few years ago....    Regards, Pete

The pairs valve can still leak if you left it attached to a vacuum tube.

[Pete-S]

Hi again.

Can't remember now, I'll check this evening when I get home, thanks.

[KiwiCol]

Rip the pairs out & block off the pipes.

[Kiwifruit]

Have said this before. My problem was intermittent but it was over fuelling with similar symptoms as yours.
I couldn't find the cause, took it to a dyno guy. It was running fine. Straight away he says it's the clutch switch. Put a new one on. Thought I'd fixed it as it didn't play up in ages. Then it decided it was time to play up again. I was quite cross as its hard to fix an intermittent problem.
I could put it away and it was running like shit, popping , spitting and backfiring. Next morning it'd start and idle away happily not to play up for another three weeks.
I don't know what connections are in there but I pulled the headlight out separated all the multiplugs in there and sprayed with contact cleaner. Popped them back together and it hasn't played up since. Have no idea what's in the headlight, perhaps someone here knows.
Happily our relationship is back on a respectful footing with no swearing. 

[Pete-S]

Thanks to everybody who contributed. After pulling every damned sensor off and checking as per the manual (to no avail ) I rechecked the two new sensors that I assumed were fine. Turns out the TPS was chucking out wildly different readings once the bike was up to temp. So, another £100 for another one and we're back to normal and running well. Still got the C28 error but that's a problem for November😁.

Happy riding

Regards

Pete