05-14-2023, 06:50 AM
(05-14-2023, 05:44 AM)Nachodaddy_imp Wrote:(05-13-2023, 11:37 AM)Obi-wan Kenobi_imp Wrote: Hello There,You can change out every part on this bike except the ECU and you will still have the same problem. I spent $700 to have a new IACV installed and it didn't make a bit of difference. While the smoke was clearing from burning seven hundred dollar bills, I read Power Dubs' advice to replace my ECU and a post by someone in South Korea who took his to his local shop where they replaced the ECU and the problem went away. So I bought a new one (not a used one on EBAY) and it worked fine and still does, just like Power Dubs said it would.
My CB1100 has been experiencing high idle issues similar to other on this forum. I have spent a good amount of time reading posts hoping that someone has already figured this out for me. But I could not find someone with the exact same symptoms.
The problem I experience is that the idle RPM is about 1,500 with the clutch fully in, and the idle RPM is about 2,000 when partially out (But still dis-engaged). I have learned to ride with using two fingers to pull in the clutch. This results in my other fingers behind the clutch. When the clutch is in this position, the engine is at 2,000 RPM.
I dont think that the problem is related to the IACV because when I first start the engine it warms up at 1500 RPM and then settles at 1100 RPM. Only when I start riding does the idle never drop below 1500 RPM (clutch fully in) or 2000 RPM (clutch in with two fingers)
I think that the problem is related to the TPS because when I ride with it unplugged, the engine idles right at 1000-1100 RPM. My theory is that there is something wrong with the middle zone of the sensor. At 1500 RPM idle I get 0.5 v from the signal line, and I get 5 v on the power line.
The help I need is sourcing a new TPS. I tried cross referencing compatible part numbers and bought one for $16. That one rotated the wrong way and was no good for me. I ended up taking the OEM one off the bike, and then put it back on. Does anyone know a compatible TPS part number?
I had thought it was: 16402-REJ-W01
Compatible part numbers per random Ebay listing:
Manufacturer Part Number
16402 REJ W01, 16402 REJ 003, 16402 PWA 003
Interchange Part Number:
JT7H, JT7H20410, TPS008-03, TPS113, GEGT7610-158, 16402-RAA-A01, 16402-RAC-A01, TPS-H112, TPS-H113, JT6HB, T42002, 16402-RAA-A02, 16402-REJ-W01, T42004, 977-024, HAJT7HARK
Any other ideas are welcome. Maybe my brain is fried from thinking about this too much.
I cannot tell you why it did work for people who replaced the IACV, or even why it worked to change MY ECU, but it did when I changed it. I ordered a new one from Partzilla and my bike has run fine since. No, I repeat NO problems since. Yes, $478 ($500 with shipping and tax) is expensive, but so are Corbin seats and Road Comet windshields. I agree that Honda should replace it free, but they disagree.
Disconnecting the TPS puts the bike in "Limp-Home" mode, to my understanding, and allows the bike to run fine except the "check-engine" light comes on and it won't rev over 5,000 RPM. You can ride it fine that way, but it DOES NOT MEAN THAT IS THE PROBLEM.
Read my LIPS! It's the ECU!
So you go ahead and replace your TPS and IACV and waste money as long as you have it to burn, but this problem will NOT go away until you put the new ECU in.
The part number is 38770-MGC-A24.
Originally the part number was 38770-MGC-A23. The change in part number tells me that Honda found a flaw and replaced it.
Replacing yours with a used one is very likely to result in the same problem.
I wish you all the best of luck in solving this problem, but I am convinced that the ECU is the problem and I hope it works for you as it did for me.
The last few years it seems that late model bike ECU firmware have been undergoing iterations of updates to combat challenges as a result of meeting the Euro 5 emission standard. Honda was also affected by it. It seems now by 2023 the dust has mostly settled as manufacturers tweaked out the ECU bugs.
Some Euro 4 bikes needed ECU firmware updates too, but thankfully for many it wasn't as a challenging as Euro 5. I cannot imagine how the next generation of bikes fair as Euro 6 puts a further stranglehold on the fuel emissions.
