St1300 cutting out

[DannoXYZ]

So my question is, what is the normal warmup sequence that may be starting to fail? I should add that it's perfectly fine the rest of the ride.

I. With initial cold-start, ECM just blindly injects petrol and fires spark to get bike started. There's additional cold-start enrichment amount of petrol based upon IAT and ECT readings. Can be +25% to account for lower vapourisation of petrol at lower temperatures.

II. Once engine is spinning, ECM inspects TPS, MAP sensor and RPM readings to look up 3D maps and arrive at proper injector duty-cycle and ignition-advance.

III. When ECT indicates engine is partially warmed up, cold-start enrichment is turned off and ECM consults O2-sensors for fuel-trim.

This might be time when you're noticing unruly behavior from engine. Might want to measure ECT, IAT, TPS, MAP and verify they are reporting signals appropriately. Also verify O2-sensor signal with oscilloscope. Wonky O2-sensor signals can trick ECM to significantly throw off AFR and cause stumbling.

 

[irideforlife]

Sounds exactly like my issue and i cannot find the problem

 

[irideforlife]

I. With initial cold-start, ECM just blindly injects petrol and fires spark to get bike started. There's additional cold-start enrichment amount of petrol based upon IAT and ECT readings. Can be +25% to account for lower vapourisation of petrol at lower temperatures.

II. Once engine is spinning, ECM inspects TPS, MAP sensor and RPM readings to look up 3D maps and arrive at proper injector duty-cycle and ignition-advance.

III. When ECT indicates engine is partially warmed up, cold-start enrichment is turned off and ECM consults O2-sensors for fuel-trim.

This might be time when you're noticing unruly behavior from engine. Might want to measure ECT, IAT, TPS and verify they are reporting signals appropriately. Also verify O2-sensor signal with oscilloscope. Wonky O2-sensor signals can trick ECM to significantly throw off AFR and cause stumbling.

How would i do that as i dont understand what i should do

 

[DannoXYZ]

Follow service manual's procedure for testing each sensor and verify they are responding appropriately for conditions. Here's test for MAP sensor.

It's very basic and cursory test to only catch outright component failures. But, worn-out sensors that's out-of-calibration will skew operating parameters for ECU to cause stumbling and other undesired behaviors. So I prefer to add additional tests to MAP-sensor to verify that outputs proper signal under idle and partial-throttle conditions as well to verify calibration is correct. Vacuum leaks in manifold boots and 5-way tee to MAP-sensor will throw off readings and cause ECU to inject incorrect amounts of petrol. So connect vacuum-gauge with rubber-T to MAP sensor to see what vacuum-levels are in engine at idle and 3000rpms to verify there's no leaks.

Do manual's test for every single other sensor: TPS, IAT, ECT, etc.

Same with O2-sensor, analyse output with warmed up engine and make sure it's not tricking ECU with incorrect data.

 

[wjbertrand]

The battery replacement fixed my instantaneous shutdown that reset the trip meter. But I still experienced a loss of power (stalling) while underway. It's only a momentary stall and pulling in the clutch and goosing the throttle brought it back to normal operation. This occurred two times on a 250 mile ride yesterday. In both cases, it was minutes after shutting the bike off for a break. I also noticed a cold idle behavior where the bike will idle fine during warmup and then at one point five minutes in, it drops RPM and stalls. It fires right up again and idles normally (1200 RPM). This isn't a case where it's losing idle because the fan kicked in. It truly seems like there is some programmed transition point after startup that it wants to stall. So my question is, what is the normal warmup sequence that may be starting to fail? I should add that it's perfectly fine the rest of the ride.

This sounds similar to the problem I had with my '05 (thread called "Ignition Problem") a few years back. My bike would cut out right around 4,200 RPM, but only after fully warmed up and only when at light throttle such as when cruising. When the engine was below full operating temperature (less than 3 bars) it ran perfectly. I could also accelerate from below 4,200 RPM, right through that speed and beyond without a hiccup. Researching this I learned that the transition from open to closed loop operation happens only at about 1/2 redline, with the engine fully warmed and at light throttle. Even when fully warmed the ECM goes into open loop at full throttle or engine speeds above ~1/2 of redline, and my engine ran perfectly under open loop conditions. I never figured out what was wrong with it (and yes I did try replacing the O2 sensors) but I suspect there is a defect or malfunction somewhere in ECM regarding the transition from open to closed loop operation. My problem didn't raise it's ugly head until I had almost 150,000 miles on the bike though.

 

[STPaulK]

This sounds similar to the problem I had with my '05 (thread called "Ignition Problem") a few years back.

Yes I recall that and I sure hope it's not something like that. But wasn't your issue more of a stumble point in the RPM band that was getting worse? Mine is more like a flat out starved (or way over lean) that would probably kill the bike if i didn't pull in the clutch and play around with the throttle. Didn't you swap every component in the ignition and fuel system, including the ECM?

 

[Tdinova]

That's what I said...


My symptoms was once warm the bike acted like it was out of fuel, idle perfect
Replaced --- fuel pump, oem fuel fiter, 2 coils, 4 wires, 4 caps, speed sensor, 4 spark plugs, fuel pressure regulator, new vacuum lines, cleaned 5 T, Coolant temp sensor, fuel pump relay, cleaned kill switch, cleaned fuel canister lines.... Still bad.

My fix was the crank position sensor... I never took it for diagnosis cause $139.00 per hr.. sensor was under $100

Enjoy

 

[wjbertrand]

Yes I recall that and I sure hope it's not something like that. But wasn't your issue more of a stumble point in the RPM band that was getting worse? Mine is more like a flat out starved (or way over lean) that would probably kill the bike if i didn't pull in the clutch and play around with the throttle. Didn't you swap every component in the ignition and fuel system, including the ECM?

Yes, I replaced every sensor, tried swapping ECMs, replaced the entire wiring harness, checked for mechanical issues (compression, leak down, vacuum leaks).

It was more like a stumble but if I kept it at the same RPMs it would feel like it was dying, opening or closing the throttle to get away from the troublesome RPMs would stop it as would opening the throttle all the way at that RPM.