All of a sudden the CEL light comes on. So I pull over & check oil, water, temps etc. all ok. No leaks, no smells. I start it up and all seems ok so I start limping home. After a few minutes it starts getting grumpy around idle but no issues under throttle. It eventually stalls at traffic lights but starts & runs under throttle. I get back ok and scratch my head. Checked battery & cables all ok., all sensors seem to be plugged in. So I pull the plugs (Pulstars with >20,000klm). Electrode on plugs appears to wearing down quite a bit. One of the screw on caps at the top of the plug is badly discoloured/dirty, along with the corresponding plug coil connector inside the rubber boot. I clean all this up and reinstall the plugs but behaves exactly the same. I'm thinking IACV. I've cleaned it once before at valve time over 20,000k ago. Done a few dirt rides but nothing really nasty dust-wise. Looking forward to getting back to Sydney to plug it into OBDII diagnostic & see what that tells me. Any ideas? N.B. It runs fine, just will not idle, AT ALL, only with throttle. Will not start without throttle either.
can you twist the top cap of that one Pulstar? One of mine failed like that and PaulC i think had even worse damage where the entire core came loose. That plug on mine clearly overheated a bit and was discolored.
I thought about the previously reported fuel filer issue but I'm skeptical. It runs normally when under throttle, but I haven't ruled it out. It's probably about time I pulled the tank, pump & filter to take a look. Both screw tops on the Pulstars came off, if not with a tad of persuasion. Only one was discoloured but no damage to either plug was noticed, other than the electrode getting pretty small. The more I think about it the more I suspect the IACV.
You need to get the CEL codes first to make sure you are working in the correct direction. The CEL works with the ECU, not oil or coolant levels but it will kick a code for too many misfires or if battery voltage is low.
UPDATE CEL has gone off a couple of times but come straight back on again. It has also decided to resume idling on occasions briefly (both with CEL on and off) then refuses again. Bike is still rideable but seems to be running cooler, abot 2 bars below half way and ambient temps are quite warm. There is a funny fuel smell from the exhaust, maybe crook fuel. But the AFR's do seem to be messed up. Ambient temps on the dash seem reasonably accurate but do change a little. Today bike started backfiring at around 3-3,500 rpm with light throttle coasting but took off under more open throttle. I'm now considering one or all of either, bad fuel, crook plugs, AIT, IACV, O2 sensor.
problems on around Idle only..? I would suspect the Idle Actuator on the blink. How does it could start?
Ok Wayne dropped around and we hooked up the GS911. Error codes on IACV, O2 sensor & stater relay. It appears that O2 & starter relay codes could be caused by crook/dirty IACV due to it causing start up conditions out of range. We tested it, cleaned it, tested it again and in the end the error code didn't return. Wayne is a bit concerned about chaffing in the wiring loom that may be contributing. I checked that and it seems good. So at this stage with the bike apart I'm going to do a somewhat premature valve clearance check, throttle body, air box/filter clean, upgrade injector & pull the tank to clean & check the fuel filter as has been posted previously. I'll get it running again but leave the plastics off in case the IACV continues to misbehave. Keep you posted.
Did you ever try it with new spark plugs? When I installed the pulstars, I got a cel. I do not remember the code it threw, or if I even had my gs911 at the time. I know when I put in good plugs the cel went off. One plug dropping could lower the internal temps of the engine, fuel not burning completely.
These Pulstar plugs have been great for over 25,000 klms. They are somewhat worn but appear to be igniting ok under throttle. I've run the bike before on a single plug and that creates worse running than I'm encountering, but it still idled, not like I'm experiencing now. I'm pretty certain it's something to do with IACV.
I just finished putting the bike back together. Cleaned the IACV and TB thoroughly. Drained & cleaned the tank & checked pump & filter. Found a bit of chaffing in the harness along the fuel tank but no wire damage so re-wrapped it. Airbox looked great, no dust at all. Very happy with the 3D air filter mod. Checked valve clearances and all within spec. Fresh fuel and ignition on with no CEL. After priming it started right up and idled as it should, around 2k while cold then settled at ~1500-1600. I ran it until the fan came on and all seems fine. No funny smell from the exhaust and no hunting idle or stalling. A ride will have to wait for a few weeks but but I'm confident it will be ok. I was just about to pull the trigger on a new IACV but will hang on to the $200 odd. Lesson- clean that IACV every chance you get. Will conclude in a few weeks after I ride it.
Just an update... I've been riding the bike for a couple of weeks and all seems pretty normal now. I upgraded the fuel injector. Starting is back to great again. It fires straight up, hot or cold. there's been the odd stumble here & there but nothing major. I can't say I noticed any change with the bigger fuel injector. Still plan on doing an adaptation reset and will let you know how that goes.
