CB1100 Idle speed instability problem

[pdedse]

Riko, thanks again for your help, having looked at all the clues we have up to this point my suspicion is that we are looking at a tps fault that creeps in over time in a small batch of bikes.

It explains why it takes some time before the fault appears and slowly gets worse.
It explains why it sometimes initiates after driving in a hot situation.
It explains why a wot reset works but only very briefly.
It explains why the kill switch reset works but only briefly.
The bad spot is still there and wears out more over time.

It may be that honda has difficulty finding the fault because their sensors give very little problems due to good engineering ( speculation ) and are not familiar with the problem.

The next problem is the diagnosis itself, even a technician with an oscilloscope would have difficulty finding the bad spot on the sensor, let alone a digital multimeter for this purpose, and because the sensor still reads mostly ok there is no fault code, the ecu does not look for a spotty reading, it only registers very low or high ( wiper broken ) voltage before it sets a code.

So the replacement of the tps or the body and do an a-b comparison is the best test i can come up with so far.

cheers max

Slowly gets worse...does it? Mine started on a warm day last July. First high idle for a few weeks (off and on), then low (off and on), then back to high, back to low, then both go away for a few rides, then back again. A few members report that their issues simply went away. What? How is that possible? Not saying I don't believe them, but that's strange.

What kind of mechanical problems simply "go away"? If a high/low idle issue really goes away, then was there any part that was truly faulty? Or, is it possible there was dirt / bad contact / crimped wire that with vibration or whatever, "corrected itself" and therefore the idle issue "went away"?

Please look at [url=http://cb1100forum.com/forum/showthread.php?tid=10073&pid=187614#pid187614]JDVALERO's post #34

And [url=http://cb1100forum.com/forum/showthread.php?tid=10073&pid=187944#pid187944]JDVALERO's post #52

This is one of the few cases that I recall reading where someone actually found something tangibly "wrong", fixed it, and had a positive change--apparently a twisted prong at the TPS connector. He says that after "fixing that the problem went away".

I checked my TPS connector. I didn't see any twisted prong, but I did clean with CRC electronic cleaner and a shot of air to both male/female ends, and then added a small amount of dialectical grease to contact points. 5 rides since and I've had two, brief instances of low idle at 900rpm, both occuring after an a good hour of riding...but nothing like before and upon turn off and restart idle immediately was fine at 1000. No high idle. BUT...the ambient temps are a lot cooler of late, 38-53 degrees instead of 55-75 during October and November.

It's at least something that others can try to see there's any improvement. I may not be able to confirm till warmer days come in about 4-5 months. I do ride throughout the winter and if the problem returns, I'll sqwak about it.

[SportsterDoc]

I will continue to assert that there may be more than one cause for idle symptoms.

Also, there is more than one possibility with the TPS:
1. ECM power output from A9 to TPS and MAP does not provide 5 vdc, +/- 0.25 vdc (rare)
2. Any of the three wires to/from TPS damaged (can be checked by resistance values, while wiggling wires)
3. Connector pins/sockets not properly mating (visual inspection, plus unplug/re-plug)
4. Internal contacts are damaged/dirty/surface of resistor has crud (remove TPS and spray contact cleaner inside, alternating with clean compressed air...may or may not work)
5. Resistor damaged (erratic voltage, rather than linear, from closed to open)

Voltage reads will tell a lot.

A poor/damaged connection can make or break with thermal expansion/contraction.
For Harley-Davidson Sportsters with nose cone ignition modules (ended in 2003), intermittent failure was/is common. Typically intermittant failure could be replicated by applying heat from a hairdryer to aid with the diagnosis.

A crack in the 4 way or 5 way vacuum hose connector could be affected by thermal expansion/contraction.

A loose intake hose (8 clamps) could be affected by thermal expansion/contraction.

Crud on the resistor, moved by wipers/contact could move.

If an IACV issue, crud may affect piston operation, even if the stepper motor is being properly driven by the ECM.

Max deserves credit for not only probing the IACV, adding LEDs and producing a video, but for thinking out loud about the TPS to share thoughts for discussion.

Not easy diagnosing by remote...it is very much limited by available input.

[max]

Thanks pdedse, i was going to ask about this fix, i would not exclude the tps connector, you are now the second to have cured your issue, that i s good news.
Also thanks for the tho links, that helped a lot jdvalero had a low voltage code, so the pin in question was actually the leftmost one, ( +5v ) i think, if it makes bad contact it will open and the voltage will go low.
He correctly states that he THINKS the one he poins at is suspect but it is not.

I like to thank him for taking the picture and posting the fix!

The way the tps connector is installed bothers me a bit, the small wires may be under stress, so it's also a suspect in my opinion and if anyone has a look at theirs be advised to not force the connector in the tps, it should connect fairly easy, if not the contacts could end up mis-aligned and to provide some room in the wiring the tank needs to be lifted and the plastic cover removed with a philips screwdriver.

i also like to stress that trying to adjust the tps by rotating it is not recommended at all unless a very good understanding is achieved on how to proceed, pogun advised this and i would like to repeat his wise words.

Thanks all for the input max

[SportsterDoc]

Thanks pdedse, i was going to ask about this fix, i would not exclude the tps connector, you are now the second to have cured your issue, that i s good news.
Also thanks for the tho links, that helped a lot jdvalero had a low voltage code, so the pin in question was actually the leftmost one, ( +5v ) i think, if it makes bad contact it will open and the voltage will go low.
He correctly states that he THINKS the one he poins at is suspect but it is not.

I like to thank him for taking the picture and posting the fix!

The way the tps connector is installed bothers me a bit, the small wires may be under stress, so it's also a suspect in my opinion and if anyone has a look at theirs be advised to not force the connector in the tps, it should connect fairly easy, if not the contacts could end up mis-aligned and to provide some room in the wiring the tank needs to be lifted and the plastic cover removed with a philips screwdriver.

i also like to stress that trying to adjust the tps by rotating it is not recommended at all unless a very good understanding is achieved on how to proceed, pogun advised this and i would like to repeat his wise words.

Thanks all for the input max

Rotating is for initial (0.5 vdc throttle closed) calibration when replacing.
If the center position is not outputting 0.5 vdc throttle closed, I'd check the increased voltage for linearity as it is opened, as well as 4.5 vdc WOT.

As for intermittent issues, see post 7 of this thread:

http://xlforum.net/vbportal/forums/showt...+connector

The poster is a very high mileage all weather rider.
Re Curly Joe spreadsheet:
736cc issue was low battery voltage
Ericio69 cured by throttle body replacement (no diagnostic help, as problem could be vacuum, IACV or TPS)
Jeff Hawk: IACV replaced
Johnf514 IACV replaced
Mangus replaced IACV and EOT, without curing, leaving vacuum or TPS as possible culprits
Rolls "cured" issue with hard riding, which may have "exercised" IACV, etc.
Sandhog reported temp fix by cycling kill switch, suggesting IACV issue.

[pdedse]

Thanks pdedse, i was going to ask about this fix, i would not exclude the tps connector, you are now the second to have cured your issue, that i s good news.
Also thanks for the tho links, that helped a lot jdvalero had a low voltage code, so the pin in question was actually the leftmost one, ( +5v ) i think, if it makes bad contact it will open and the voltage will go low.
He correctly states that he THINKS the one he poins at is suspect but it is not.

I like to thank him for taking the picture and posting the fix!

The way the tps connector is installed bothers me a bit, the small wires may be under stress, so it's also a suspect in my opinion and if anyone has a look at theirs be advised to not force the connector in the tps, it should connect fairly easy, if not the contacts could end up mis-aligned and to provide some room in the wiring the tank needs to be lifted and the plastic cover removed with a philips screwdriver.

i also like to stress that trying to adjust the tps by rotating it is not recommended at all unless a very good understanding is achieved on how to proceed, pogun advised this and i would like to repeat his wise words.

Thanks all for the input max

Haha, I am not so optimistic as to call it a cured issue. At least one member has reported that issues disappear over winter only to return in the summer. But every ride free from the high/low idle bug is greatly appreciated, as all are your guys' efforts at pinpointing the matter.

I wish I lived closer to one of you three/four electronic minded members, as I would happily ride by and donate my bike for a weekend to let folks do testing mentioned of late here. I may be able to probe for vacuum leaks as Doc stresses, but I also know my limitations in the realm of electronic diagnosis.

[SportsterDoc]

Thanks pdedse, i was going to ask about this fix, i would not exclude the tps connector, you are now the second to have cured your issue, that i s good news.
Also thanks for the tho links, that helped a lot jdvalero had a low voltage code, so the pin in question was actually the leftmost one, ( +5v ) i think, if it makes bad contact it will open and the voltage will go low.
He correctly states that he THINKS the one he poins at is suspect but it is not.

I like to thank him for taking the picture and posting the fix!

The way the tps connector is installed bothers me a bit, the small wires may be under stress, so it's also a suspect in my opinion and if anyone has a look at theirs be advised to not force the connector in the tps, it should connect fairly easy, if not the contacts could end up mis-aligned and to provide some room in the wiring the tank needs to be lifted and the plastic cover removed with a philips screwdriver.

i also like to stress that trying to adjust the tps by rotating it is not recommended at all unless a very good understanding is achieved on how to proceed, pogun advised this and i would like to repeat his wise words.

Thanks all for the input max

Haha, I am not so optimistic as to call it a cured issue. At least one member has reported that issues disappear over winter only to return in the summer. But every ride free from the high/low idle bug is greatly appreciated, as all are your guys' efforts at pinpointing the matter.

I wish I lived closer to one of you three/four electronic minded members, as I would happily ride by and donate my bike for a weekend to let folks do testing mentioned of late here. I may be able to probe for vacuum leaks as Doc stresses, but I also know my limitations in the realm of electronic diagnosis.

It needs to be misbehaving, unless there is a stored code.
Have you snugged your intake clamps?

[pdedse]

Thanks pdedse, i was going to ask about this fix, i would not exclude the tps connector, you are now the second to have cured your issue, that i s good news.
Also thanks for the tho links, that helped a lot jdvalero had a low voltage code, so the pin in question was actually the leftmost one, ( +5v ) i think, if it makes bad contact it will open and the voltage will go low.
He correctly states that he THINKS the one he poins at is suspect but it is not.

I like to thank him for taking the picture and posting the fix!

The way the tps connector is installed bothers me a bit, the small wires may be under stress, so it's also a suspect in my opinion and if anyone has a look at theirs be advised to not force the connector in the tps, it should connect fairly easy, if not the contacts could end up mis-aligned and to provide some room in the wiring the tank needs to be lifted and the plastic cover removed with a philips screwdriver.

i also like to stress that trying to adjust the tps by rotating it is not recommended at all unless a very good understanding is achieved on how to proceed, pogun advised this and i would like to repeat his wise words.

Thanks all for the input max

Haha, I am not so optimistic as to call it a cured issue. At least one member has reported that issues disappear over winter only to return in the summer. But every ride free from the high/low idle bug is greatly appreciated, as all are your guys' efforts at pinpointing the matter.

I wish I lived closer to one of you three/four electronic minded members, as I would happily ride by and donate my bike for a weekend to let folks do testing mentioned of late here. I may be able to probe for vacuum leaks as Doc stresses, but I also know my limitations in the realm of electronic diagnosis.

It needs to be misbehaving, unless there is a stored code.
Have you snugged your intake clamps?

It needs to be misbehaving, unless there is a stored code.
I think this is why the CS manager at the Honda dealership was reluctant to make any promises had I left the bike with them. The week prior to taking it in, the idle was up and down, the day I went in...rock solid.

Thanks pdedse, i was going to ask about this fix, i would not exclude the tps connector, you are now the second to have cured your issue, that i s good news.
Also thanks for the tho links, that helped a lot jdvalero had a low voltage code, so the pin in question was actually the leftmost one, ( +5v ) i think, if it makes bad contact it will open and the voltage will go low.
He correctly states that he THINKS the one he poins at is suspect but it is not.

I like to thank him for taking the picture and posting the fix!

The way the tps connector is installed bothers me a bit, the small wires may be under stress, so it's also a suspect in my opinion and if anyone has a look at theirs be advised to not force the connector in the tps, it should connect fairly easy, if not the contacts could end up mis-aligned and to provide some room in the wiring the tank needs to be lifted and the plastic cover removed with a philips screwdriver.

i also like to stress that trying to adjust the tps by rotating it is not recommended at all unless a very good understanding is achieved on how to proceed, pogun advised this and i would like to repeat his wise words.

Thanks all for the input max

Haha, I am not so optimistic as to call it a cured issue. At least one member has reported that issues disappear over winter only to return in the summer. But every ride free from the high/low idle bug is greatly appreciated, as all are your guys' efforts at pinpointing the matter.

I wish I lived closer to one of you three/four electronic minded members, as I would happily ride by and donate my bike for a weekend to let folks do testing mentioned of late here. I may be able to probe for vacuum leaks as Doc stresses, but I also know my limitations in the realm of electronic diagnosis.

It needs to be misbehaving, unless there is a stored code.
Have you snugged your intake clamps?

Not yet; since cleaning the TPS connector the bike has run well (about 2 weeks, 5 rides of 1/2 hour to 2 hours, shorter 10-15 minute rides). I kinda want to let it go for awhile to see if either high or low idle returns. If neither does, maybe we're beginning to isolate the affected area at the TPC connector? If the issue returns, then on to the intake clamps.

[max]

pdedse, in the interest of slowly ruling out the iacv , has your 1100 ever deviated from warming up at 1500 rpm?

[pdedse]

pdedse, in the interest of slowly ruling out the iacv , has your 1100 ever deviated from warming up at 1500 rpm?

I can't remember what it does during the summer, but now it's cold idle speed starts right at 1500rpm, and then I believe drops to 1200 after 1/4 mile before stabalizing at 1000 shortly after that.

[SportsterDoc]

Thanks pdedse, i was going to ask about this fix, i would not exclude the tps connector, you are now the second to have cured your issue, that i s good news.
Also thanks for the tho links, that helped a lot jdvalero had a low voltage code, so the pin in question was actually the leftmost one, ( +5v ) i think, if it makes bad contact it will open and the voltage will go low.
He correctly states that he THINKS the one he poins at is suspect but it is not.

I like to thank him for taking the picture and posting the fix!

The way the tps connector is installed bothers me a bit, the small wires may be under stress, so it's also a suspect in my opinion and if anyone has a look at theirs be advised to not force the connector in the tps, it should connect fairly easy, if not the contacts could end up mis-aligned and to provide some room in the wiring the tank needs to be lifted and the plastic cover removed with a philips screwdriver.

i also like to stress that trying to adjust the tps by rotating it is not recommended at all unless a very good understanding is achieved on how to proceed, pogun advised this and i would like to repeat his wise words.

Thanks all for the input max

Haha, I am not so optimistic as to call it a cured issue. At least one member has reported that issues disappear over winter only to return in the summer. But every ride free from the high/low idle bug is greatly appreciated, as all are your guys' efforts at pinpointing the matter.

I wish I lived closer to one of you three/four electronic minded members, as I would happily ride by and donate my bike for a weekend to let folks do testing mentioned of late here. I may be able to probe for vacuum leaks as Doc stresses, but I also know my limitations in the realm of electronic diagnosis.

It needs to be misbehaving, unless there is a stored code.
Have you snugged your intake clamps?

It needs to be misbehaving, unless there is a stored code.
I think this is why the CS manager at the Honda dealership was reluctant to make any promises had I left the bike with them. The week prior to taking it in, the idle was up and down, the day I went in...rock solid.

Thanks pdedse, i was going to ask about this fix, i would not exclude the tps connector, you are now the second to have cured your issue, that i s good news.
Also thanks for the tho links, that helped a lot jdvalero had a low voltage code, so the pin in question was actually the leftmost one, ( +5v ) i think, if it makes bad contact it will open and the voltage will go low.
He correctly states that he THINKS the one he poins at is suspect but it is not.

I like to thank him for taking the picture and posting the fix!

The way the tps connector is installed bothers me a bit, the small wires may be under stress, so it's also a suspect in my opinion and if anyone has a look at theirs be advised to not force the connector in the tps, it should connect fairly easy, if not the contacts could end up mis-aligned and to provide some room in the wiring the tank needs to be lifted and the plastic cover removed with a philips screwdriver.

i also like to stress that trying to adjust the tps by rotating it is not recommended at all unless a very good understanding is achieved on how to proceed, pogun advised this and i would like to repeat his wise words.

Thanks all for the input max

Haha, I am not so optimistic as to call it a cured issue. At least one member has reported that issues disappear over winter only to return in the summer. But every ride free from the high/low idle bug is greatly appreciated, as all are your guys' efforts at pinpointing the matter.

I wish I lived closer to one of you three/four electronic minded members, as I would happily ride by and donate my bike for a weekend to let folks do testing mentioned of late here. I may be able to probe for vacuum leaks as Doc stresses, but I also know my limitations in the realm of electronic diagnosis.

It needs to be misbehaving, unless there is a stored code.
Have you snugged your intake clamps?

Not yet; since cleaning the TPS connector the bike has run well (about 2 weeks, 5 rides of 1/2 hour to 2 hours, shorter 10-15 minute rides). I kinda want to let it go for awhile to see if either high or low idle returns. If neither does, maybe we're beginning to isolate the affected area at the TPC connector? If the issue returns, then on to the intake clamps.

As a fellow/former Sportster rider, we should be accustomed to checking over fasteners regularly. On that basis, it would be good to check the 8 clamps, just as routine maintenance.