TPS Sourcing because of High Idle

[Obi-wan Kenobi_imp]

Hello There,

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.

[GoldOxide_imp]

Strong research OwK, and strange behaviour indeed.

I can't help by confirming the part number, but this Forum can potentially heal.

I can welcome you to the Forum. So welcome!

Hopefully a useful confirmation comes along shortly.

[PowerDubs_imp]

Hello There,

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.

Correlation does not imply causation.

It is common for a bike / car to default to a baseline (emergency) map running situation when various components are unplugged. That does NOT mean that the part unplugged is faulty.

[Cormanus]

There's a parts site (https://www.bike-parts-honda.com/honda-motorcycle) where you can search for parts by their number. It say P/N cannot be found. Nor does a search for a Throttle Position Sensor reveal any parts.

Try having a search for the part number on that site.

[Lord Popgun]

We had this discussion once but IIRC we didn’t reach a conclusion.

The TPS we have is a JT6H The Number on mine is JT6H 21206 and the TPS is a Kehin.

A Google search brings up a lot of JT6H units, but none says 21206. I don’t know if it matters.

It is also possible that other Honda bikes use it and may be available separately from the dealer. IDK.

[PowerDubs_imp]

Yea- but sourcing the TPS doesn't matter when it isn't the cause of the problem.

Just opening a possible additional problem by messing with it- there is a reason it is held in place with torx and white out- to discourage.

And this is coming from someone who has no problem or fear whatsoever with taking things apart.

But if you want to read others who have already done the same- http://cb1100forum.com/forum/showthread.php?tid=10073

Personally- if my bike ever starts to do a high idle, I will update the ECU to the new software revision- as I believe that is the answer.

[Lord Popgun]

Don’t get me wrong Dubs. I agree with you totally. Just trying to answer the original question.

The TPS circuit is easy enough to test and verify if needed. I don’t think it needs it here though.

[Nachodaddy]

Hello There,

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.

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.
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.

[max]

Obi, Following on and agreeing with all the above offered advice i also think the tps is fine, presents the correct voltage at the closed position of the valves ( just measured mine at 0.489 volts ) and only makes it harder to do the repair because if replaced adds an unknown factor in the mix.
The tps acts like the slide needle adjustment for the correct air/fuel mixture in carbs, be careful to understand this concept before adjusting/changing the tps.

Nacho's advice is the best we have at the moment, many members have had total success with the software/replacement procedure, some have had success with the iacv motor but we all agree the software is the problem.

You may have come across my disconnect tip procedure of the tps which helps but is sensitive in the startup.

Up to you and thanks for posting.

[PowerDubs_imp]

Hello There,

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.

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.
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 good news is now- we have the capability to read and write the ECU for only the cost of an adapter cable to plug into an OBD cable... I bought both from the tuning cable company- but for fun I tried one of my old VAGCOM VCDS cables and it worked fine.

So- we can read / write- and we already have a copy of Guhl's tune for ign timing, rev limiter, speed limiter, etc.

What we need now is a copy of the A24 software (hint hint) and we can mix the tuned ECU stuff into that and then everyone can just reflash their existing boxs with the best combo of everything.