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Ok so update....

I put two smallish chokes on each wire coming from the fan directly at the fan, and one slightly bigger over both wires just in front of that. I also threw a small choke on the knock sensor wire right at the sensor... Unhooked the battery while doing this just to reset everything.

Rode to work (75ish degrees F) and rode all the way there without anything. But this was likely the ECM resetting. Riding back home (95ish F) light came on 10ish minutes in at 185 degrees while cruising on the highway. Never stopped long enough for the bike to get hot. Riding both to and from work today I got the light but much earlier/sooner than previously so....

Im guessing the chokes are doing SOMETHING but Idk if its the something enough to eliminate the problem. Ill probably throw one on the fuel pump just for grins and another choke at the knock sensor itself just for good measure.
 

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Why choke the knock sensor.? I would take that one off. ECU looks for specific signals from this sensor to determine if system ok and for knock. I would just attempt to get clean unadulterated signal from this wire.
 

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Why choke the knock sensor.? I would take that one off. ECU looks for specific signals from this sensor to determine if system ok and for knock. I would just attempt to get clean unadulterated signal from this wire.
Thats a good point. I yanked off the chokes on the Knock sensor this morning. Ill do a couple rides today and see what happens.
 

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Discussion Starter · #25 ·
Here is my input on chokes. I did just the fan wires with one each. I threw in a known faulty ECU that would trip the FI light above 3000 rpms in the first 5 minutes of riding to just see what would happen. So, I rode out did about 30 miles no light. Thinking maybe, maybe not - Yesterday I did 215 miles in 90 degrees F. Group ride for part - putting along at 35 mph for over 90 minutes. Bike was full hot with fan running almost constant. No light even once. No lag, and no drop off. This from an ecu that I was about to scrap.

Dug into the signal generator on the scope - Signal noise reduction was about 60% of what I was showing before without the chokes. Signal was cleaner and did not spike over 8v even revving the engine or holding t 4000 for 30 seconds.

So what does this mean? I have no friggen' clue. Seem that the reduction in RFI is helping (thanks greatly to SGTWOODY'S input) but the layout and is still up in the air for the best set up and which wires are causing the issue. Will work on it more with the scope this week as time permits.

I would assess this as signs of hope but not conclusive yet.


Keep the feedback coming - any other testers would help.
 

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So after riding for a couple days Im noticing 2 things.

First, I am still getting the light, but its occurring sooner and at lower temps than before (no fan running) so its possible Im doing something wrong or something isnt fully connected. I pulled everything apart again today to make sure its all seated properly and Ill try to get a few more tests in this week (looking like rain though and Im moving next weekend).

The second is that it seems to be not running quite as hot. It still gets hot but it doesnt rush up to max temps every time I stop. I dont know if this has anything at all to do with the situation but... I noticed it.

@medic407 , did you just run one on each wire and nothing else? Ive also considered sticking one on the ECM power main but I havent gotten to it.

EDIT: Just circled the block... fresh ECM reset, light came on at 124F and 20mph... hmmm...
 

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Discussion Starter · #27 ·
@SgtWoody I ran one on each wire -also did the reset before the first ride not the long ride. Light came on this am after 10 minutes -bike was cool like your situation - so now I'm as confused as you are. rechecked the signal at the ECU input from the knock and It s showing reduction as before . Did a Code memory on the ECU before clearing the codes and a MAP sensor code popped underlying the knock sensor. Checked it and had a loose connection at the sensor. Chasing gremlins. I'm going to pull the fan chokes and try one just at the ECU for the next round. See where that leads. Something else not sure if related, Ran ok on long ride using a magnetic tank bag. Todays ride was clean tank and had more issues. just realized that sitting here so going to check signals in AM with bag on to see if that made any difference. I cant see how that would affect anything but I won't know till I checks the readings.
 

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@SgtWoody I ran one on each wire -also did the reset before the first ride not the long ride. Light came on this am after 10 minutes -bike was cool like your situation - so now I'm as confused as you are. rechecked the signal at the ECU input from the knock and It s showing reduction as before . Did a Code memory on the ECU before clearing the codes and a MAP sensor code popped underlying the knock sensor. Checked it and had a loose connection at the sensor. Chasing gremlins. I'm going to pull the fan chokes and try one just at the ECU for the next round. See where that leads. Something else not sure if related, Ran ok on long ride using a magnetic tank bag. Todays ride was clean tank and had more issues. just realized that sitting here so going to check signals in AM with bag on to see if that made any difference. I cant see how that would affect anything but I won't know till I checks the readings.
I still think you are on to something. The light coming on faster is what doesn't make sense to me. In theory that means it could be receiving a cleaner signal and is detecting a problem "easier" but... if there's no problem, what is it detecting? Like I said I'm packed to move right now but once I transition, I have 3 different knock sensors I'm going to try swapping out and see if maybe its a sensor issue.

I don't know how much you're willing to dive in but I'm also curious if there's back-feeding of voltage from either the fan freewheeling or just generally though the ground. I know smaller scale, brushed motors that are controlled by micro-controllers typically run a diode in line to bleed off excess voltage and to keep it out of the controller. I also keep mentally coming back to the ground wires since some people report the issue going away after a loom fix. I performed the loom fix myself but I didn't notice any real corrosion on the wires.
 

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Next update....

During my move the bird got packed into the barn and I couldnt get it out for about a week. Since I pulled it out the light has been out and has not come back on for the last four days of riding. And its definitely been HOT here in South Texas... So Im still hopeful that maybe something just finally reset and the ferrites are keeping the noise out?
 

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Next update....

During my move the bird got packed into the barn and I couldnt get it out for about a week. Since I pulled it out the light has been out and has not come back on for the last four days of riding. And its definitely been HOT here in South Texas... So Im still hopeful that maybe something just finally reset and the ferrites are keeping the noise out?
Did you ever get closure / outcome on this?
 

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Did you ever get closure / outcome on this?
Its definitely back. Ive been rennovating my house so my tinkering time isnt there but commuting daily it glows on. Ive found if I let it sit for 3-4 days between rides the light will reset and make it a good 30-45 minutes into riding before coming on, but once its on it stays on until I let it sit again.
 
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