BTW, these drawings by @SpikingJC are amazing! Thank you!
Wiring schematics - ALL years and models
/r
Brad
Wiring schematics - ALL years and models
/r
Brad
Article [13] ST1300 - FI Codes (MIL) Malfunction Indicator Lamp
- Thread starter Mellow
- Start date
Only if you continue to run with the light illuminated; IME it does not affect fuel consumption when no light is illuminated as the bike is not in reversion fuel mapping like it is when the fault triggers/light is illuminated...still seeing upper 40mps (and low 50mpg a few times too, now that I've replaced the aftermarket TwoBros mine had when I bought it with an OEM exhaust) The bike also sounds/feels different throughout the RPM band for some reason, if anyone can explain that...maybe because it's now seeing the correct backpressure through the tubes that the aftermarket didn't present? It is definitely quieter too.
I do see a significant MPG drop when I lose track and accidentally trigger the fault; once reset (quick engine cutoff OFF>ON, restart), it takes a few minutes for the throttle sensitivity to disappear and everything to be back to normal. I have not yet worked through the troubleshooting steps as my right side connector is completely melted (possible support of Igofar's claim of higher heat but having ridden a lot in FL and NV, I can't say for sure when it actually melted or relate that to when I started getting the codes) and I'm done trying new ECMs (been through three of them with same end result) until I can get to the sub-harness to replace it and see if that resolves anything. Exceeding the RPM limit/time should be less of an issue with the new McCruise (love it!) that I can just set at 3950RPM (slight red of the 4K line showing just above the needle) and forget about throttling for awhile on the highway. I also need to update my picture...over 151k now.
Thank you for sharing your experience
I ordered a knock sensor sub-harness. My sensor connectors have pretty much disintegrated. Is there any way to replace the harness without removing the throttle bodies?
just kind of a response to post 26 - can anyone explain...
the best real world example of back pressure affecting performance I had was with a gradually deteriorating / coroding flexible segment in my 92 Accord I drove it from a slight exhaust leak through to a bad exhaust leak; even then the noise wasn't any worse than some of the aftermarket mufflers so who cares was the rationale
What I noticed after a while was a gradual loss of performance and this was over a considerable period. No fault codes or rough running, just gradually diminished power Got a new flex connector from a wreckers, no tune up no other changes and power was back to normal
the best real world example of back pressure affecting performance I had was with a gradually deteriorating / coroding flexible segment in my 92 Accord I drove it from a slight exhaust leak through to a bad exhaust leak; even then the noise wasn't any worse than some of the aftermarket mufflers so who cares was the rationale
What I noticed after a while was a gradual loss of performance and this was over a considerable period. No fault codes or rough running, just gradually diminished power Got a new flex connector from a wreckers, no tune up no other changes and power was back to normal
Brad,
I could be wrong, but I don't think the wires for the knock sensors run underneath the throttle bodies. It's my understanding that those wires run through a large, grey, connector/junction on either side of the bike near where the frame and seat sub-frame come together. I've also heard that it's a real PITA to remove and replace.
If your wires have continuity to the ECM, you might consider just replacing the connectors. Ironically, someone started a thread on these connectors recently. A link to the thread with possible options follows: https://www.st-owners.com/forums/threads/knock-sensor-connector.191396/#post-2595405. Replacing the connectors is likely far less time-consuming and will cost less than replacing the sub-harness. Since I have not replaced the sub-harness myself, I will admit that I don't know the true degree of difficulty. Nevertheless, I wanted you know there was another option.
Chris
Thank you Chris. I have had the throttle bodies off/on once and would like to avoid another adventure if possible.
To replace the knock sensor sub harness, I had to remove the throttle bodies. Multiple leads, to thread to connect to several points.
The sub harness has leads to:
See below illustrations.
After replacing the old sub harness with a new harness (32109-MCS-700), still getting FI light.
Against my better judgement, I picked up a “used” "good" ECM off ebay ($350). Expected result. Seems kinda hard to diagnose a good/bad ECM. I'm not sure who would let anyone swap a suspect ECM onto a "running-fine" bike. When I swapped ECMs, still had code. I suspect I bought a bad ECM. Back to where I started. For now, gonna ride with the code.
The sub harness has leads to:
- Neutral Switch
- Oil Pressure Sensor
- Speed Pickup Sensor (3p)
- Left Knock Sensor
- Knock Sensor Shield
- Right Knock Sensor
- Knock Sensor Shield
- Ground Connector
See below illustrations.
After replacing the old sub harness with a new harness (32109-MCS-700), still getting FI light.
Against my better judgement, I picked up a “used” "good" ECM off ebay ($350). Expected result. Seems kinda hard to diagnose a good/bad ECM. I'm not sure who would let anyone swap a suspect ECM onto a "running-fine" bike. When I swapped ECMs, still had code. I suspect I bought a bad ECM. Back to where I started. For now, gonna ride with the code.
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Code 25 persists. Circling back to this thread after one observation. The code first appeared shortly after using my new (to me) Gerbing heated jacket/pants liners. This in addition to also using Honda heated grips. I'm wondering if the current draw had something to do with the code appearing.
QUESTION: Is anyone familiar with the Honda ECU Test Harness to say whether the harness is pinned out straight thru? For the reported $1,500 price tag, while the connectors are about $20/set, I might try building one myself.
Help..My Fault light just started coming on the 2006 ST1300. It appears to only blink once when I turn off kill switch. Im supposed to do a bike trip in two days...and wonder if I should ignore for the time being or..Don't risk it..! Going to be putting on about 1500 miles or so..Thoughts anyone?
woodybelle
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I would want to know what the code is before the trip or else I may worry the whole trip about the cause.
Yea, that was my thoughts, ended up renting a Kaw Concourse for the trip..Bumma, was about to turn over a 100k on the odometer, sitting @ 98,800
The one blink is a code for the Manifold Air Pressure module. Your 5-way T may have a blockage or one of the tubes has cracked. To check this, you will need to remove the bottom of the airbox to expose the throttle body. Most who have replaced the tubes and cleaned the 5-way T have been able to clear the fault code.Yea, that was my thoughts, ended up renting a Kaw Concourse for the trip..Bumma, was about to turn over a 100k on the odometer, sitting @ 98,800