Misfire and running rich

[Eric GSX1400K3]

When was the last time the throttle bodies were synchronised?

[Kiwifruit]

Mine was doing the running rich pop bang cut out thing. I could ride it the next day with no issues. Then it would decide to play up again. Had to hold the throttle at 3000rpm just to stop it stalling. Was a real pain took me an age to sort it. I believed it to have been wiring connectors  inside the headlight. I replaced the clutch switch, made no difference. Hasn't missed a beat since.

[grog]

Remember your probs Col, reckon i might as precautionary, unplug & spray every connection in there.Running fine but want to keep it that way.Good suggestion 👍

[Hooli]

I've known two 14s with long term running rich issues that were a bugger to find, both were the oil temp sensor. The fast idle always worked cause the ECU runs on a timer after checking the oil temp at start up (the timings are in the workshop manual).

It's an easy one to check. There's a two wire plug running up the RH side of the airbox, black & black/white wires I think, just measure the resistance between them. There's a chart in the workshop manual & values so you'll know roughly what it should be. The ones I've seen fail should have been about 100 KOhms but were 1,000 KOhms. I think it was KOhms, but it was deffo that far out & doesn't cause a FI light as that just checks the sensor is plugged in.

[Hooli]

Another thought. The ends of the plug leads rot, sometimes it's worth pulling the plug caps off & trimming the leads slightly. That'd cause a weak spark & apparent rich running as it's not burning the mixture properly.

[Eric GSX1400K3]

I've known two 14s with long term running rich issues that were a bugger to find, both were the oil temp sensor. The fast idle always worked cause the ECU runs on a timer after checking the oil temp at start up (the timings are in the workshop manual).

It's an easy one to check. There's a two wire plug running up the RH side of the airbox, black & black/white wires I think, just measure the resistance between them. There's a chart in the workshop manual & values so you'll know roughly what it should be. The ones I've seen fail should have been about 100 KOhms but were 1,000 KOhms. I think it was KOhms, but it was deffo that far out & doesn't cause a FI light as that just checks the sensor is plugged in.

just checked mine as it also appears to be running rich.

The manual says you need 4.5-5.5V with the ignition on at the wire TO the sensor. I have 4.77V there so all good there.

With ignition off, resistance FROM the sensor should be 61.3k Ohm at 20deg C oil temp.  Currently here it's 34deg C ambient, bike hadn't run in 24h, so I assumed oil would be at around similar. I got 31.8kOhm at the sensor.  As a check, I got an icypole out of the freezer and put that on the sensor top whilst checking resistance.  This sensor has an inverse relationship between temperature and resistance (i.e reduced resistance as temperature increases).  I watched the resistance slowly count up as my icypole sat on the sensor.  This confirmed that the sensor is reading correct.  I need to recheck when ambients are  a bit lower, but I think I've ruled out the oil temp sensor for now.  Next on my list is injectors.

[Daaef]

When you start it does it do the fast idle then ease back to 1100?

Yep, the fast idle and then drop to 1100 is fine albeit running rough

[Daaef]

When was the last time the throttle bodies were synchronised?

Good question, don't have the service history and I haven't done it since picking it up in Nov. Would be worth doing.

[Daaef]

Mine was doing the running rich pop bang cut out thing. I could ride it the next day with no issues. Then it would decide to play up again. Had to hold the throttle at 3000rpm just to stop it stalling. Was a real pain took me an age to sort it. I believed it to have been wiring connectors  inside the headlight. I replaced the clutch switch, made no difference. Hasn't missed a beat since.

Thanks I'll recheck these connectors. I did clean and reconnect the LH switch block connector when I did the clutch switch

[Daaef]

Thanks brains trust for all the input. Will start with the oil temp sensor and go from there.

[Hooli]

When was the last time the throttle bodies were synchronised?

Good question, don't have the service history and I haven't done it since picking it up in Nov. Would be worth doing.

If you're going to sync the throttles do it before resetting the TPS, or it'll need doing again afterwards.

[Hooli]

Just had a thought.

Check all the vacuum pipes as they are known to go brittle & split which results in poor running at low revs/throttle.

[seth]

Just had a thought.

Check all the vacuum pipes as they are known to go brittle & split which results in poor running at low revs/throttle.

Good shout buddy I'd forgotten about those too

[Daaef]

With ignition off, resistance FROM the sensor should be 61.3k Ohm at 20deg C oil temp.  Currently here it's 34deg C ambient, bike hadn't run in 24h, so I assumed oil would be at around similar. I got 31.8kOhm at the sensor.  As a check, I got an icypole out of the freezer and put that on the sensor top whilst checking resistance.  This sensor has an inverse relationship between temperature and resistance (i.e reduced resistance as temperature increases).  I watched the resistance slowly count up as my icypole sat on the sensor.  This confirmed that the sensor is reading correct.  I need to recheck when ambients are  a bit lower, but I think I've ruled out the oil temp sensor for now.  Next on my list is injectors.

Hmm. Seems like mine might be ok then. Measured 32k Ohm when engine not warmed up (not completely cold either) and then when warmed up to the point when the oil cooler fan kicked in it dropped to 1.8k Ohm. This indicates to me its working as expected

[Hooli]

When I had a problem with the oil temps sensor the readings were very out.

As an estimation from the graph in the manual it's about 100k Ohm at 0c, I was seeing over 1,000k Ohm.