CB1100 Idle speed instability problem

[SportsterDoc]

To show a different scale for sensor resistances, this link is for my 2003 Jeep Wrangler TJ, for the IAT and coolant sensors: http://www.jeepforum.com/forum/f9/normal...ng-979267/

Thus, we need a chart from the Honda factory service manual.

[SportsterDoc]

Pending more info on the EOT, I've been researching information on the TPS, such as resistance values. Hopefully they are in the factory service manual.

Also checking for a source for the TPS, since Honda does not seem to sell it, other than with the full throttle body unit. No success, thus far. The TPS unit on my 2014 is a Keihin JT6H 40226.

JT6H is Keihin's designation for a throttle position sensor.
Found nothing on the 40226 unit.

It may be common to another Honda, but I've found nothing to cross.

Without input on data from members with idle issues, I am not finding much else to be of possible help.
Meanwhile, potential for a vacuum leak includes
8 clamp bolts (8 mm/Phillips head) for throttle body to head clamps
4 rubber intake boots
9 vacuum hoses
1 four way vacuum fitting
1 five way vacuum fitting

[Riko_imp]

Many views, some comments about bad fuel, nonsense in my country, only one solution, a whole trottle body replacement, under the second hand warranty, wich is one year in Belgium.




So I'm lucky that the issue exposed itself during that period.
Since the replacement back in June '16, the idle has been rock solid in all seasons and all conditions.

My dealer told me the procedure is that they inform Honda of a issue that could potentially lead to a recall after an investigation of the 'faulty' parts.
Thats why the dealer has to hold the parts for a certain period in wich Honda can investigate.

All this time I haven't heard anything from my dealer...either they didn't pick it up or if they did, they did't deem it worthy for a general or regional recall.

They replaced my throttle body on advice from a Honda dealer in The Netherlands wich applied the same method to cure the issue....

[the Ferret]

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.

[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.

[Lord Popgun]

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.

[SportsterDoc]

Many views, some comments about bad fuel, nonsense in my country, only one solution, a whole trottle body replacement, under the second hand warranty, wich is one year in Belgium.




So I'm lucky that the issue exposed itself during that period.
Since the replacement back in June '16, the idle has been rock solid in all seasons and all conditions.

My dealer told me the procedure is that they inform Honda of a issue that could potentially lead to a recall after an investigation of the 'faulty' parts.
Thats why the dealer has to hold the parts for a certain period in wich Honda can investigate.

All this time I haven't heard anything from my dealer...either they didn't pick it up or if they did, they did't deem it worthy for a general or regional recall.

They replaced my throttle body on advice from a Honda dealer in The Netherlands wich applied the same method to cure the issue....

Be really interesting to know what aspect of the throttle body assembly was at fault:

1. TPS (not available separately...wonder if it removes easily?)

2. IAC (available separately) 16430-MJF-DO1 and common to CBR1000RR ABS, CBR1000RR, CB1000R, CBR1000S, CBR600RR, CB600RRABS, Cb500F, CB500X... https://www.bikebandit.com/oem-parts/det...sch=848000

3. Throttle bodies not seated to intake (anyone snug the band bolts?)

4. Vacuum leak, such as a crack in the 4 way or 5 way vacuum tube fitting

5. Fuel injector(s)

[Lord Popgun]

Hummm, that vacuum fitting is interesting. The ST1300 has one and is a known problem area. Both clogging up and cracking or breaking pretty easily. The ST forum guru keeps them in stock at his house for repairs (he fixes/tunes a LOT of ST’s). I’ve been meaning to order a couple myself.

[SportsterDoc]

Hummm, that vacuum fitting is interesting. The ST1300 has one and is a known problem area. Both clogging up and cracking or breaking pretty easily. The ST forum guru keeps them in stock at his house for repairs (he fixes/tunes a LOT of ST’s). I’ve been meaning to order a couple myself.

Very interesting. A crack would suck air and increase idle.
Be good to replace with brass, but finding more than a 3 way would be a challenge.
The 5 way (part 18) is 17201-MCJ-003 ($7 list)
The 4 way (part 19) is 17201-MCZ-003 ($5.60 list)

https://www.bikebandit.com/oem-parts/201...#sch848000

Not stating that this is the problem, but worth checking.

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.

I cannot see what the fasteners (small Phillips or Torx or Allen?) are which secure it (covered with white paint, after torque check), but it has about 10 degrees of mechanical radial adjustment. Mine appears to be mounted in the exact center of that adjustment. A slot should mate with the end of the throttle body shaft and the two wire connector is easily removed by squeezing the interlocking clip. If removed and reinstalled in close to the same position, the key on, engine off open/close throttle 2-3 times calibration should allow easy replacement.

It is a 5 vdc unit, so voltage should range from under 1 volt to under 5 volts, as affected by the resistor position. Resistance at WOT and closed throttle may be helpful.

Anything in the FSM about normal vacuum readings?

[pdedse]

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 [url=http://cb1100forum.com/forum/showthread.php?tid=10073&pid=187944#pid187944]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.