CB1100 Idle speed instability problem

[the Ferret]

Fixed? Hahahaaaa. Yes, until it isn't.

Sad but true

[Lord Popgun]

Doc,

EOT—in the DTC index (fault codes) there are 2 for the EOT. One is EOT sensor circuit high voltage (more than 4.93v) and one for low voltage (less than 0.04v)

TP sensor—one for low voltage (less than 0.3v) and one for high voltage (more than 4.93v)

IAT sensor—one for low voltage (less than 0.07v) and one for high voltage (more than 4.93V)

MAP sensor- one for low voltage (less than 0.2v) and one for high voltage (3.9v). One fault is for hose connection, no values of anything on the DTC list.

As for the TPS troubleshooting and checks, there are 3 pages of steps. I’m not typing all that. Check your PM.

[peterbaron]

Doc,

I’ll look in the manual for the TPS. There is some info in there but I can’t remember detals. If nothing else, I know it lists min/max voltages.

Even though the TPS is not available separately, one knowledgeable member posted that is was the same a one off some car. He based this off the min/max voltages and actually tweeked his some. [Guys, DO NOT try this unless you are very experianced with this kind of thing. As noted before, there is NOTHING in the service manual for adjusting. Just big warnings to not touch it.]

I spent a couple hours trying to find that post and could not. He said it was a pretty common one, IIRC.

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>.
NOTHING wrong with popgun statement at all !!!!!!

Just want to add 2 cents...and I am NOT that mentioned knowledgeable member...

2013-14 HONDA-CB1100 :: TPS voltage & resistance test WITHOUT removing TPS
Test with digital multimeter (for advanced users)..
TPS (variable resistor) has 3 wires/pins: power supply(+), ground(-) and signal::

NEVER disconnect/reconnect TPS connector if IGN is ON, EVER
This is NOT a field fix to your problem - TPS test only
You do all these tests at your own risk/I assume no responsibility

IF you have a TPS problem = most likely you would have a DTC (history, pending or active, possible ELO/MIL ON).....or.....poor connection somewhere ...

WHEN ENGINE FULLY WARMED UP AND IDLING - WIGGLE/PRESS BLACK/3 PIN TPS CONNECTOR (near your L leg) and see if there is some RPM fluctuation.. = SIMPLE TEST FOR EVERYONE.

These advanced tests might be helpful::

TPS wiring::
black/yellow = power supply (+)
black/green = ground (-)
black/red = signal
This Honda diagram, I have, SUCS BIG TIME !!!!! = due to NO pin numbers

TEST 1
*IGN ON, Engine/stop switch OFF, backprobe ground and signal = about 0 Volts = OK when throttle is closed. NOTE:: I do not think it will be dead on 0/ZERO Volts, I think it will be slightly above..like 0.1 - 0.2 V
*TPS sensor VOLTAGE must smoothly/continuously increase/decrease when throttle is opening/closing respectively...so you MUST have smooth Voltage operation from about 0V (closed) to about 4.75 - 5.25 V at WOT = OK

TEST 2
*IGN OFF, Engine/stop switch OFF, DISCONNECT black TPS connector (3pins)
* TURN IGN ON, do NOT start (while TPS connector disconnected)
* Measure the voltage between black/yellow(+) and black/green(-) = MUST be within 4.75 - 5.25 V = OK

** Tell me what is your voltage between black/green(-) and black/red (signal), PLEASE = ? V **

TEST 3
*IGN OFF
* Disconnect black/3pin TPS connector
* Measure TPSensor side (NOT harness) resistance between black/red & black/green = within 0.5 - 1.5 kOhm = OK..
Manual does NOT tell me TPS resistance at WOT or/and between ground(-) and power supply(+)...but from my TPS experience would be above 1.5 kOhms

This entire TPS circuit consists of 4 connectors: TPS (black 3 pins), SUB black/10 pin, JOINT black/12 pin and ECM/ECU gray/33pin...and poor contact might be anywhere...would first start with TPS connector as per tests 1,2,3

Do NOT want to make complicated but this is how it works and how to test it
MAKE sure your throttle cable has some slack !!!
After disconnecting ANY connector:: check it, clean it, apply connector enhancer for better conductivity, please.

pb

[max]

Hi again doc, some more info and a video.

Voltage tested at engine cold is 4.04 volts ( 2000 ohms ) 1500 rpm
and hot engine measures 0.909 volts (300 ohms ) 1050 rpm

Interestingly i could not get the engine to idle below 1050 rpm? ( low rpm issue ).

Seems perfect for the a/d converter in the cpu in the ecm ( geeks only ).http://cb1100forum.com/forum/images/smilies/cool.gif

Please be careful not to damage the little terminals inside the eot sensor, this is a bit of an advanced test which requires knowledge of electronics and connectors!

Really good request of the vin numbers, it may relate to a particular batch that had something different done.
The issue is that japan does not have any faulty bikes to test and that makes it hard for them to come up with an answer,
so if we can give them some numbers they may find something that relates to this batch of bikes.

New youtube video on today's test with the relationship between the eot sensor and change of rpm

; https://youtu.be/aDkx_6tIeDs

as usual; cheers Max

[max]

Just some pics to show how i tested the rpm eot relationship.

first pic is what is connected and type of connectors ( everything is wired in parallel )

second is with engine lukewarm r eot = 1000 ohm 3.468 v and 1340 rpm.

third is engine warmed up just enough for the rpm to settle at 1050 rpm at 2.17 v at 371 ohm.

So the point where the engine settles at 1050 rpm appears to be 2 volts across the eot sensor,

[SportsterDoc]

I don't think its a vacume leak problem which to me would cause high idle issues only. THis " problem" has componants of both high and low idle, therefore I think its some kind of sensor problem, but I am not an engineer.

May not be the issue...but want to check as many possibilities as possible

Small leak = high idle
Big leak = engine dying

BTW, in the Hunting RPM thread, post 72, popgun posted the EOT resistance value
"From the manual: STANDARD: 2.4-2.9 Kohms (20 degrees C/68 degrees F)"

Surprised that it is not a chart with temperature ranges.

May not be the issue...but want to check as many possibilities as possible

Small leak = high idle
Big leak = engine dying
...
But if it were vacuum leak related, wouldn't the high idle happen consistently, as in "all the time"? I've had high and low idle on the same ride. Stop, turn off engine, restart, problem goes away, sometimes it doesn't.

jdvalero pulled the TPS sensor plug and found a physical issue with wiring and says that this has fixed the issue for him. I hope that the problem truly is fixed for him, because that would be one of the few cases where something concrete was spotted as being "faulty", a fix applied, and idle issue goes away.

Per suggestions near that post, I pulled that plug, cleaned connectors and applied a tiny bit of dialectic grease, reconnected. I've done 3 rides since...1st time with bike fully warm, 1 instance of low idle at 750rpm. Tuned off bike, started and idle returned to normal. Last two rides of 1/2 hour to 1 hr, no issues at all. Fixed? Hahahaaaa. Yes, until it isn't.

May depend upon the nature of the leak:
1. intake boot may be affected by thermal expansion
2. cracked/loose hose may be affected by movement
3. cracked fitting (4 way or 5 way) may be affected by heat and/or movement. Small crack = high idle...crack opens and bike barely idles.

Not saying this is the issue, but worth checking:
a. Snug clamp bolts
b. Check hoses are not hardened and pushjed all the way on.
c. inspect fittings
d. apply unlit propane and listen for idle speed change

Just some pics to show how i tested the rpm eot relationship.

first pic is what is connected and type of connectors ( everything is wired in parallel )

second is with engine lukewarm r eot = 1000 ohm 3.468 v and 1340 rpm.

third is engine warmed up just enough for the rpm to settle at 1050 rpm at 2.17 v at 371 ohm.

So the point where the engine settles at 1050 rpm appears to be 2 volts across the eot sensor,

Good info and great pics!

Hi again doc, some more info and a video.

Voltage tested at engine cold is 4.04 volts ( 2000 ohms ) 1500 rpm
and hot engine measures 0.909 volts (300 ohms ) 1050 rpm

Interestingly i could not get the engine to idle below 1050 rpm? ( low rpm issue ).

Seems perfect for the a/d converter in the cpu in the ecm ( geeks only ).http://cb1100forum.com/forum/images/smilies/cool.gif

Please be careful not to damage the little terminals inside the eot sensor, this is a bit of an advanced test which requires knowledge of electronics and connectors!

Really good request of the vin numbers, it may relate to a particular batch that had something different done.
The issue is that japan does not have any faulty bikes to test and that makes it hard for them to come up with an answer,
so if we can give them some numbers they may find something that relates to this batch of bikes.

New youtube video on today's test with the relationship between the eot sensor and change of rpm

; [url=https://youtu.be/aDkx_6tIeDs]https://youtu.be/aDkx_6tIeDs

as usual; cheers Max

Great visual depiction of correlation of lowering EOT voltage with lowering of idle speed. In the first test as both were dropping, then the EOT voltage climbed , which should indicate oil colder, instead of warming up.
Somehow added resistance is getting into the EOT-ECU circuit:
Air pocket at EOT possible???

Confirm that the voltage probe is at ECU connector?

If so, this would eliminate
a. Bad connection at EOT and/or ECU
b. Partially broken wire

and points to a defective EOT

I just got home from a long meeting with some paperwork to do tonight, so I am not completely focused, but my initial thinking is that your video indicates that it is NOT
A. an internal ECU / ECU program issue
B. not a vacuum issue
C. Not an IAC issue
on your bike.

There are many different bikes, both manufacturer and model, with EFI idle issues...there may be many different causes.

Doc,

I’ll look in the manual for the TPS. There is some info in there but I can’t remember detals. If nothing else, I know it lists min/max voltages.

Even though the TPS is not available separately, one knowledgeable member posted that is was the same a one off some car. He based this off the min/max voltages and actually tweeked his some. [Guys, DO NOT try this unless you are very experianced with this kind of thing. As noted before, there is NOTHING in the service manual for adjusting. Just big warnings to not touch it.]

I spent a couple hours trying to find that post and could not. He said it was a pretty common one, IIRC.

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>.
NOTHING wrong with popgun statement at all !!!!!!

Just want to add 2 cents...and I am NOT that mentioned knowledgeable member...

2013-14 HONDA-CB1100 :: TPS voltage & resistance test WITHOUT removing TPS
Test with digital multimeter (for advanced users)..
TPS (variable resistor) has 3 wires/pins: power supply(+), ground(-) and signal::

NEVER disconnect/reconnect TPS connector if IGN is ON, EVER
This is NOT a field fix to your problem - TPS test only
You do all these tests at your own risk/I assume no responsibility

IF you have a TPS problem = most likely you would have a DTC (history, pending or active, possible ELO/MIL ON).....or.....poor connection somewhere ...

WHEN ENGINE FULLY WARMED UP AND IDLING - WIGGLE/PRESS BLACK/3 PIN TPS CONNECTOR (near your L leg) and see if there is some RPM fluctuation.. = SIMPLE TEST FOR EVERYONE.

These advanced tests might be helpful::

TPS wiring::
black/yellow = power supply (+)
black/green = ground (-)
black/red = signal
This Honda diagram, I have, SUCS BIG TIME !!!!! = due to NO pin numbers

TEST 1
*IGN ON, Engine/stop switch OFF, backprobe ground and signal = about 0 Volts = OK when throttle is closed. NOTE:: I do not think it will be dead on 0/ZERO Volts, I think it will be slightly above..like 0.1 - 0.2 V
*TPS sensor VOLTAGE must smoothly/continuously increase/decrease when throttle is opening/closing respectively...so you MUST have smooth Voltage operation from about 0V (closed) to about 4.75 - 5.25 V at WOT = OK

TEST 2
*IGN OFF, Engine/stop switch OFF, DISCONNECT black TPS connector (3pins)
* TURN IGN ON, do NOT start (while TPS connector disconnected)
* Measure the voltage between black/yellow(+) and black/green(-) = MUST be within 4.75 - 5.25 V = OK

** Tell me what is your voltage between black/green(-) and black/red (signal), PLEASE = ? V **

TEST 3
*IGN OFF
* Disconnect black/3pin TPS connector
* Measure TPSensor side (NOT harness) resistance between black/red & black/green = within 0.5 - 1.5 kOhm = OK..
Manual does NOT tell me TPS resistance at WOT or/and between ground(-) and power supply(+)...but from my TPS experience would be above 1.5 kOhms

This entire TPS circuit consists of 4 connectors: TPS (black 3 pins), SUB black/10 pin, JOINT black/12 pin and ECM/ECU gray/33pin...and poor contact might be anywhere...would first start with TPS connector as per tests 1,2,3

Do NOT want to make complicated but this is how it works and how to test it
MAKE sure your throttle cable has some slack !!!
After disconnecting ANY connector:: check it, clean it, apply connector enhancer for better conductivity, please.

pb

Peter
Excellent info
Thank you much...will finish evaluating in the morning

This allows present and future member to evaluate (albeit carefully), if the need arises.

In the automotive world TPS failures are somewhat common, especially above 100,000 miles and typically cause a limp mode. I would expect few issues on a bike with much lower miles, but still very surprised that a TPS cannot be purchased separately.

[max]

Yes doc, the connector goes to the ecu.

it was disconnected from the eot sensor and connected to the variable resistor only and the values on the video are with the variable resistor ( potmeter ).

On the pics the eot sensor WAS connected and the voltage displayed was across the eot sensor, measuring voltage as the engine warmed up just as would be the case as per normal, i just started lukewarm instead of cold.
the point of interest was the settle poin at which the engine reaches 1050 rpm.

I know it is a bit fluffy, cheers max

[dave]

Dave

If you will provide resistances of the EOT at a couple sensor temperatures...

Then if someone with a FSM will post the acceptable ranges, we can determine if it is an EOT sensor issue.

Temperature sensors have various ranges, but all I have seen have max resistance cold and minimum resistance hot.

On a 5 vdc circuit, it will output 4 point something vdc cold and point something vdc hot. If the unit is faulty and/or a poor connection (causing voltage drop), a lower than scale read will fool the ECU into thinking it is too hot and the ecu may take counter measures.

Also, someone with a FSM, is there a trouble code for EOT out of range hi or out of range low?

Hi Sportsterdoc. I replaced the EOT sensor and it did nothing. This sensor is extremely sensitive to temperature - just holding it in your hand will raise the temperature enough to considerably change the resistance. Both my old and new sensors checked out according to the Honda service manual (but my body temperature would cause them to go out of spec). If I hadn't already replaced the EOT sensor I might try your suggestion, although it may be difficult to record an accurate temperature. Thank you for the suggestion.

My bike has been on a high idling kick. Right about 1400. A little irritating


Sent from my iPhone using Tapatalk

Can you please contact Honda and let them know? The phone number and contact name is in this thread. Thank you.
Some observations; engine does not start with eot sensor disconnected and engine light comes on, it just stutters.
[/quote]
Hi Max. When I disconnect the EOT sensor on my 2014 Dlx the check engine and temperature lights both go on, but the bike starts and runs fine. Actually, when it is experiencing either the high idle or low idle condition unplugging the EOT sensor will cure the problem - but I must first turn the bike off with the key before unplugging it, and then restart it. Interesting that your bike will not restart. I wonder how other members bike would react to unplugging the EOT sensor?

[max]

Hi Dave, good to hear from you again.

A question; in general would you agree that the issue starts gradually at some point and then gets progressively worse?

Not trying to put words in your mouth , just thinking in one direction and one step at a time if that makes sense..

Cheers max

[SportsterDoc]

Dave

If you will provide resistances of the EOT at a couple sensor temperatures...

Then if someone with a FSM will post the acceptable ranges, we can determine if it is an EOT sensor issue.

Temperature sensors have various ranges, but all I have seen have max resistance cold and minimum resistance hot.

On a 5 vdc circuit, it will output 4 point something vdc cold and point something vdc hot. If the unit is faulty and/or a poor connection (causing voltage drop), a lower than scale read will fool the ECU into thinking it is too hot and the ecu may take counter measures.

Also, someone with a FSM, is there a trouble code for EOT out of range hi or out of range low?

Hi Sportsterdoc. I replaced the EOT sensor and it did nothing. This sensor is extremely sensitive to temperature - just holding it in your hand will raise the temperature enough to considerably change the resistance. Both my old and new sensors checked out according to the Honda service manual (but my body temperature would cause them to go out of spec). If I hadn't already replaced the EOT sensor I might try your suggestion, although it may be difficult to record an accurate temperature. Thank you for the suggestion.

My bike has been on a high idling kick. Right about 1400. A little irritating


Sent from my iPhone using Tapatalk

Can you please contact Honda and let them know? The phone number and contact name is in this thread. Thank you.
Some observations; engine does not start with eot sensor disconnected and engine light comes on, it just stutters.

Hi Max. When I disconnect the EOT sensor on my 2014 Dlx the check engine and temperature lights both go on, but the bike starts and runs fine. Actually, when it is experiencing either the high idle or low idle condition unplugging the EOT sensor will cure the problem - but I must first turn the bike off with the key before unplugging it, and then restart it. Interesting that your bike will not restart. I wonder how other members bike would react to unplugging the EOT sensor?
[/quote]
Dave
There is likely more than one issue affecting low or high idle.
Even though Max has documented a direct linear correlation between EOT output and idle speed, that does not seem be your issue.

The resistance value is at 20C. Warming it in your hand is expected to change the resistance.

Hi Dave, good to hear from you again.

A question; in general would you agree that the issue starts gradually at some point and then gets progressively worse?

Not trying to put words in your mouth , just thinking in one direction and one step at a time if that makes sense..

Cheers max

If that is the case it is explainable with several options:
a. Sensor deterioration
b. Loose connection/broken wire worsening
c. Vacuum leak increasing/fluctuating

You all may get weary of me mentioning vacuum leaks, but they are very common on the XLForum.