tps evaluating for ii issues

max

max

Road warrior
Thread starter
UPDATE; new procedure for tps testing.

this is another approach in diagnosing the Idle Instability Issue.

In order to isolate which of the two parts is the source of trouble on the throttle body i discovered an interesting way to isolate the tps, you unplug it!

the following video shows how to do this and what tools are required, most of us can follow this procedure.

1 if your bike runs better after the tps is disconnected that would be an indication the tps is bad.
2 if it still has the same problem after disconnection it MAY be the iacv.

During the test drive i noticed three things;
1 cold idle is at 1250 rpm.
2 throttle response is " softer " and smooth handling may be required to keep it running on startup.
3 my exhaust vacuum valve did not operate ( think the bike is in a different mode )

It appears ok to drive this way but just to be on the safe side i would not recommend long periods unplugged riding.
What may work for you is giving you the length of cable as shown in the video but leaving it connected, go for a drive and when the idle is acting up stop, disconnect the connector and see what difference it makes, even several times to make sure the method is repeatable.

If success is achieved i suggest making a video showing; difference in rpm, connector disconnected and connected possibly several times.
this can easily be done with the bike running on the side stand.
if this is done correctly it may well lead to a refund or recognition of sorts by the dealer and dispel uncertainty.

This method has been done by several service personnel and documented as such.

Let's hear your experience with this method, it has to be the simplest to date because we really need some feedback from you affected owners.


cheers max
 
Max
Thank you for the effort that you are putting into this.
I emailed you regarding details of first conclusion.

For now, just a couple comments:
1. My TPS wires have enough slack to just unplug, which I have done a couple times...but good to show how the air box side covers are removed.

2. Above the TPS, at 10 & 11 o'clock, the intake clamp screws (8mm/Phillips) for the left cylinder can been seen at video 1:32 to 1:44 minutes. This is what I have been suggesting be "snugged".
 
 
In Max's video, note the number of times the CEL blinks: 8, which is the DTC for TPS voltage. It does not specify -1 or -2 for whether voltage is low or high, but it does specify a TPS issue.
 
Hi Max. Great video, thank you. For clarification: Are you suggesting to disconnect the TPS when the high / low idle condition occurs and then seeing if this cures the problem? I will try this the next time the idle condition rears its ugly head and report back. 3 days ago my bike exhibited the worst case of low idle and stalling ever. After 20 minutes of perfect running (around town, slow speeds, stop & go), the low idle suddenly returned. The bike stalled three times, and once it even stalled when shifting from first to second gear (I can force it to keep running by increasing the RPM when stopped at a light, but to me, it sounds like an extremely lean fuel mixture). I turned the bike off with the key, and took out my wife's smart phone to video the condition but when I restarted the bike it returned to running perfectly ( and remained running perfect for the rest of the ride - about 10 more miles, a mixture of stop and go and freeway). Just to let you know, I have discovered that unplugging the EOT sensor when the low idle condition occurs will immediately cure the problem (but I always turn the bike off with the key before unplugging the EOT sensor). I have ridden my bike on multiple occasions with the EOT sensor disconnected and never experiences the low idle / stalling condition.
 
Thread starter
Dave_imp said:
Hi Max. Great video, thank you. For clarification: Are you suggesting to disconnect the TPS when the high / low idle condition occurs and then seeing if this cures the problem? I will try this the next time the idle condition rears its ugly head and report back. 3 days ago my bike exhibited the worst case of low idle and stalling ever. After 20 minutes of perfect running (around town, slow speeds, stop & go), the low idle suddenly returned. The bike stalled three times, and once it even stalled when shifting from first to second gear (I can force it to keep running by increasing the RPM when stopped at a light, but to me, it sounds like an extremely lean fuel mixture). I turned the bike off with the key, and took out my wife's smart phone to video the condition but when I restarted the bike it returned to running perfectly ( and remained running perfect for the rest of the ride - about 10 more miles, a mixture of stop and go and freeway). Just to let you know, I have discovered that unplugging the EOT sensor when the low idle condition occurs will immediately cure the problem (but I always turn the bike off with the key before unplugging the EOT sensor). I have ridden my bike on multiple occasions with the EOT sensor disconnected and never experiences the low idle / stalling condition.
Click to expand...
Thank you, Dave.
You have been very helpful and precise, i have read your comment very carefully several times.

In the past there have been at least two cases where the complete throttle body has been replaced and with 100% sucess.

There have also been other repairs performed with sucess.
as you know i have been working on the eot sensor as well but have not yet found any fault with it, but i know first hand that it is part of the process for the iacv.

My first mission is to prove or disprove the tps, because it is by far the most simplest part to work with, if we can find that unplugging it makes a decisive difference on several bikes we are a step closer, if we find that it makes no difference at all we can concentrate on the next item, but that will probably be beyond some owners to accomplish by themselves.

Think the best way to do in your case is to first make sure the tps can be unplugged by making sure the wiring is long enough to allow this by following the tips in the video so the connector is not damaged by forcing it and stretching the wires.

Then go and ride the bike ( with the camera, great idea ) and wait until the issue happens frequently ( reliably enough ) whilst filming unplug the tps when the engine is running, blip the throttle and see if it has any effect, plug it back in and so on several times.
the reason is that it needs to be repeatable to be proof enough, if it has the desired effect you can go for a short ride and repeat the process, what we want is conclusive evidence.
what you are doing is an a-b test back to back, several times, i'm sure you know what i mean

It may not help at all, but you are the closest to an answer we have so far and i really appreciate your help.
Happy new year;max
 
Hi Max, thank you, and happy new year to you too! I haven't had time to ride nearly as much as I would like because other priorities keep getting in the way (like a leaking crankshaft seal on my truck, a leaking head gasket on my car, and clogged plumbing in my house), but I will definitely check the wire on my CB this weekend and have it ready to unplug the next time I ride. My idle problem comes and goes at random, so please understand I may not have a answer for you quickly. Thanks again for all the work you're doing!
 
Likely possibilities for an intermittent issue:
1. Failing component
2. Poor connection

This is supported by the FSM, page 5-15:

DTC 8-1 (<0.3 vdc) "Loose or poor contact of TP sensor connector. TP sensor or its circuit malfunction"

DTC 8-2 (>4.93 vdc) "TP sensor or its circuit malfunction"

At the beginning of each sensor checking procedure, the FSM admonishes "before starting, check for loose or poor contact..."

I do not want to interfere with your teamwork with Max, Dave, but if the issue is related to the sensor, unplugging it and insuring a good connection, may end the issue.

One more thought: If a poor connection, either incoming 5 vdc power and/or 0.5 to 4.5 vdc output will be lessened. If not out of range, no DTC, but the ECM will think that the throttle is not as far open as it actually is, which would be expected to cause shorter injector pulses, making it lean, which might cause low idle and/or stalling. This should be checked before replacing the TPS.
 
Thank you Max and Sportsterdoc. My bike has never exhibited an error code, except when I unplug the EOT sensor. I checked yesterday, and I am able to unplug the connection to the TPS. I think I'll buy some contact cleaner and spray it on the connection and see if that does anything. Some members have had their idle problem corrected under warranty when the entire fuel injection was replaced; I wonder if Honda chose this repair because the TPS was faulty, and on the CB1100 the TPS is not available separately? Thank both you guys so much for all the effort you're putting into this!
 
Dave_imp said:
Thank you Max and Sportsterdoc. My bike has never exhibited an error code, except when I unplug the EOT sensor. I checked yesterday, and I am able to unplug the connection to the TPS. I think I'll buy some contact cleaner and spray it on the connection and see if that does anything. Some members have had their idle problem corrected under warranty when the entire fuel injection was replaced; I wonder if Honda chose this repair because the TPS was faulty, and on the CB1100 the TPS is not available separately? Thank both you guys so much for all the effort you're putting into this!
Click to expand...
That and a clean old toothbrush...but, more importantly, insure that all the connector contacts are fully seated into the connector insulator...not "floating" in the cavities.

Push each wire into the connector, to be sure that the contact retainig tab is seated.

This may have been the cause of more than one issue for members with idle issues
Houtman_imp said:
I think that Sportersdoc and Max put more effort in solving this problem than Honda USA does !
Click to expand...
Thanks for the thought, but popgun has also been involved.

As for Honda or dealerships, an intermittent issue is a challenge to a mechanic living off flat rates.

What we (Max, popgun & I) have been working on should provide more method and less guessing...and hopefully reasons for each step.

Based upon Sportster experience (not that my Moto Guzzi did not vibrate just as much), poor/loose connections are the cause of many, MANY, M A N Y issues.

The CB1100 is very smooth, but a single improperly seated contact can cause alot of mischief.

Try as I may, I do not seem to be able to convince anyone to check for vacuum leaks or snug the intake clamps...but I will keep preaching! These may not be a single issue, but would still insure that they are secure.
 
Try as I may, I do not seem to be able to convince anyone to check for vacuum leaks or snug the intake clamps...but I will keep preaching! These may not be a single issue, but would still insure that they are secure.
[/QUOTE]
Hi SportsterDoc. Thank you so much for all the work you're doing to help resolve this issue. Can I gain access to all of the intake clamps by lifting the rear of the gas tank, or does the tank have to be removed? Thanks to your persistence, I am going to check the clamps (asap).
 
Dave_imp said:
Try as I may, I do not seem to be able to convince anyone to check for vacuum leaks or snug the intake clamps...but I will keep preaching! These may not be a single issue, but would still insure that they are secure.
Click to expand...
Hi SportsterDoc. Thank you so much for all the work you're doing to help resolve this issue. Can I gain access to all of the intake clamps by lifting the rear of the gas tank, or does the tank have to be removed? Thanks to your persistence, I am going to check the clamps (asap).
[/QUOTE]
All eight clamps are accessible, without removing anything.
4 from the left and 4 from the right.
To check mine, I used a 1/4" drive ratchet, 6" extension with a 8mm socket.
If the bolt heads (combo 8 mm/#2 Phillips) are not exactly at 12 o'clock, a universal joint may help.

No need to over-tighten, just use a couple fingers on the wrench, close to the ratchet.
 
Dave, the clamp screws are easily accessible. Go look, you don’t have to remove anything. You do 2 sets from one side, then move to the other side for the other 2 sets. 4 screws total.

Sorry Doc, I guess you posted while I was typing.
 
Lord Popgun_imp said:
Dave, the clamp screws are easily accessible. Go look, you don’t have to remove anything. You do 2 sets from one side, then move to the other side for the other 2 sets. 4 screws total.

Sorry Doc, I guess you posted while I was typing.
Click to expand...
No problem-been there and done that!

Should get in about 100 miles today, which will take the odometer close to 3,000 miles in 2 months...time for chain lube #5.

Going to visit my dad in SoCal, next week, so the rain predicted (there and here) will not affect riding, since the CB will be garaged for a few days, anyway.
 
Our roads are covered with snow and ice. I’m not even taking the car anywhere!
 
popgun
I got 140 miles on the tank, today, before the last fuel gauge segment started flashing and indicating 37 miles remaining.

Came back with 3018 miles on the odometer.

Might be my last ride to Mt. Charelston for a while. It has been comfortable at 8,500 feet, even with a little snow alongside the road, in northern exposure shade.

This next storm will probably create a lingering ice situation for some time after. Kyle Canyon and Lee Canyon have areas of 6% to 8% grades.

URGENT - WINTER WEATHER MESSAGE
National Weather Service Las Vegas NV
248 PM PST Sat Jan 6 2018

NVZ018-019-071200-
/O.NEW.KVEF.WS.A.0001.180109T1200Z-180110T0600Z/
Sheep Range-Spring Mountains-Red Rock Canyon-
Including The Town Of Mt Charleston and Red Rock Canyon
248 PM PST Sat Jan 6 2018

...WINTER STORM WATCH IN EFFECT FROM LATE MONDAY NIGHT THROUGH TUESDAY EVENING ABOVE 7000 FEET...

* WHAT...Heavy snow possible. Plan on difficult travel conditions.
Total snow accumulations of 6 to 12 inches, with localized
amounts up to 18 inches possible.

* WHERE...Sheep Range and Spring Mountains.

* WHEN...From late Monday night through Tuesday evening.

* ADDITIONAL DETAILS...Significant reductions in visibility are
possible.
 
SportsterDoc may have just solved the high/low idle mystery! I checked the hose clamps on the throttle bodies today and all eight were loose! Two of them I turned the screws about three full revolutions before achieving an acceptable tightness! I rode the bike about 100 miles after tightening the clamps and it ran perfectly! Most of the miles were on the freeway, but I came to a full stop and put the bike in neutral no less than twenty times today, and each and every time it immediately returned to a perfect 1050 RPM idle! Before I can declare my idle issue is completely cured I must put more miles on the bike, and do some in town, slow speed, stop and go riding, and for a thorough test, I need to perform the in town riding in elevated temperatures. I will perform addition tests ASAP (hopefully next weekend), and report back. I urge any of you guys who are experiencing the idle problem to check your throttle body hose clamps, as SportsterDoc has been recommending.
 
Dave, I hope that solves it for you.
 
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