F1 light at 4000 rpm

[stealthtourer]

In 5th gear as soon as I hit around 4000 rpm Fi light goes on .I can hit kill switch off then on and blib throttle and it goes out?

 

[wjbertrand]

Either a bad knock sensor or it’s lead or the dreaded ECU permanent fault.

 

[stealthtourer]

The light stays on doesn't blink numerous times.the good thing doesn't effect bike run but keeps me from speeding as tickets add up

 

[jfheath]

Isn't 4000 rpm what you have to hold the engine to for a few seconds in order to get the fault diagnosis ?

 

[Igofar]

The light stays on doesn't blink numerous times.the good thing doesn't effect bike run but keeps me from speeding as tickets add up

It does affect the bike, and will cause the bike to run hot etc.
If you keep riding it in this condition you may find damage to the bike after a while.

 

[wjbertrand]

Isn't 4000 rpm what you have to hold the engine to for a few seconds in order to get the fault diagnosis ?

For the knock sensor to initially set a fault yes (assuming it or the ECU is faulty). Once a fault or faults are set however, no revving is necessary to read them.

 

[stealthtourer]

For the knock sensor to initially set a fault yes (assuming it or the ECU is faulty). Once a fault or faults are set however, no revving is necessary to read them.

Misunderstanding! Once I stay above 4,000 rpm the FI comes on and will stay no temp increase.tgen I can hit kill switch to off then back on and blip the throttle and its gone.I I was thinking mass air or c2o senser

 

[wjbertrand]

Misunderstanding! Once I stay above 4,000 rpm the FI comes on and will stay no temp increase.tgen I can hit kill switch to off then back on and blip the throttle and its gone.I I was thinking mass air or c2o senser

Historically it’s a bad knock sensor or a faulty ECU when it sets a code at 4000 RPM. You will need to pull the stored code to confirm. There is no CO2 sensor on the bike. Perhaps you mean an oxygen sensor? There are two of those.

 

[RiderRon]

Read the code so you know for sure what you may be dealing with. Pretty simple to do so that way you are not receiving random solutions.
Then search the forum, verify the problem and then go through the process of addressing the issue.

Article [13] - ST1300 - FI Codes (MIL) Malfunction Indicator Lamp | ST1300 Articles

The PGM-FI MIL denotes the failure codes (the number of blinks from 0 thru 33). When the indicator lights for 1.3 seconds it is equivalent to 10 blinks. When more than one failure occurs, the MIL shows the blinks in order of lowest to highest number. Code Reset: Turn the engine stop switch...

www.st-owners.com

 

[Gus1300]

Known (possibly even common) problem; I've had two ECUs so far that have 'found' the code after thousands/hundreds of miles without triggering it. No explanation as to why the ECU software goes bad but they apparently do. Good luck finding one at a reasonable price to replace it and get the fault to go away. (of course, assuming you've checked the O2 sensors and they're good)

It's not the throttle blip that resets the FI light (the engine will restart just by popping the clutch if you're still on the move), it's the power cycle via either the engine stop switch or ignition switch/key but the code is still readable using the above procedure until cleared, even when the light is off. Likely it's a 25/26 (error in the service manual noted in that they're opposite from the original printing of the 03-05 manual) indicating an O2 sensor.

My newest (current) ECU didn't trip the fault after replacing the old ECU and neither O2 sensor until months after installation when it suddenly started doing it again as well, similar to the first (original as far as I know) ECU that didn't do it for years/thousands of miles either. I have two new O2 sensors on the shelf; never swapped either since the code cleared after replacing the ECU indicating to me that it wasn't a sensor issue.

You may notice a different feel/sound with the light on due to the engine mapping the ECU is using until the notification is reset (it's not cleared via a power cycle, the light is just reset); mine was very distinct between the light on and the light off with the first ECU, I don't notice as much of a change with this ECU and run below 4k (noting Igofar's and other's comments about the risks of doing so long term) because I haven't found a decent priced replacement ECU yet and aren't willing to give up riding until I do so. I hope to provide some long term data for doing so and accept the risks mentioned in the meantime.

 

[bstig60]

Code 25/26 is the knock sensor, not the oxy sensor.

 

[core-aggie]

Code 25/26 is the knock sensor, not the oxy sensor.

Yea, and it can also be a faulty ECU. Some folks have replaced it and the code went away.

And this is NOT an ST13 anomaly ... I just spent time in BlackBird forum, in a thread from 2015-2021, where they discussed the same issue. A really great thread with lots of technical explanations.

And some oddball remedies, one being, "I switched to 98 octane and the error went away"

 

[stealthtourer]

Misunderstanding! Once I stay above 4,000 rpm the FI comes on and will stay no temp increase.tgen I can hit kill switch to off then back on and blip the throttle and its gone.I I was thinking mass air or c2o senser

C02 ì

Either a bad knock sensor or it’s lead or the dreaded ECU permanent fault.

According to codes bad knock sensor their would be several blinks leading me to believe bad ecu. I'm going to clear the code and take it from there

 

[stealthtourer]

C02 ì

According to codes bad knock sensor their would be several blinks leading me to believe bad ecu. I'm going to clear the code and take it from there

I cleared the f1 light and haven't seen the light since.running down hwy 400 at 85 for an hour or so

 

[Igofar]

Sounds like your 5 way tee was clogged up. Sometimes it will throw odd codes and confuse folks.
Check your 5 way tee, replace the vacuum lines, and do a starter valve sync, and I bet your issues don't come back.