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Diagnostic Trouble Codes & Sensor testing
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max Online
1st Service Completed

auckland
Posts: 50
Joined: Sep 2017
Post: #21
RE: Diagnostic Trouble Codes & Sensor testing
Hi Doc, some more info for the thread;

tps overall resistance; 6.25 k ohm ( yellow/black )
throttle lower position; 1.095 k ohm ( red/black )
throttle high position ; 6.05 k ohm
( all measured ref to " ground or lower section ie green/black" and tps disconnected from ecu.

Voltages;
yellow/black +4.97 volt
red/black idle 0.482 volt wot 4.45 volt
green/black 0 volt ( the black meter probe )

Voltage increases in a linear way from lower to higher position.

Hope this helps to assist with the gathering of data from the members involved.

Bonus footage; iacv operation on my bike, as usual a bit vague, the video editing program had trouble at 5% slow motion but what happens is ; on startup the iacv opens 65 steps and then closes 12 steps with a cold engine and 35 wiith a warm engine.

This happens in the blink of an eye as demonstrated at the very end of the video so i slowed it down to count the steps and direction, open and close.

the ecu does not know what position the iacv is at startup , so it always commands the valve open with 65 pulses, it then makes a decision to close x many steps based on the temperature of the eot sensor.

Whilst i had the black plastic throttle body covers off i found that mine were made on 27 july 2010, another clue.

https://youtu.be/MFA5Mk4vS3c

cheers max
12-14-2017 07:03 PM
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SportsterDoc Offline
1st Service Completed

southern Nevada
Posts: 214
Joined: Nov 2017
Post: #22
RE: Diagnostic Trouble Codes & Sensor testing
(12-14-2017 07:03 PM)max Wrote:  tps overall resistance; 6.25 k ohm ( yellow/black )
throttle lower position; 1.095 k ohm ( red/black )
throttle high position ; 6.05 k ohm
( all measured ref to " ground or lower section ie green/black" and tps disconnected from ecu.

Voltages;
yellow/black +4.97 volt
red/black idle 0.482 volt wot 4.45 volt
green/black 0 volt ( the black meter probe )

Voltage increases in a linear way from lower to higher position.

Max: Major kudos to you for the set-up, testing and video recording!
How does the FSM spec of sensor resistance between black/red and black/green of 0.5 to 1.5 K ohms correlate to your readings?

The 1/2 volt to 4 1/2 volt range seems very typical. Very important is the linear change as the throttle position changes...no bumps or hiccups.

(12-14-2017 07:03 PM)max Wrote:  ...on startup the iacv opens 65 steps and then closes 12 steps with a cold engine and 35 wiith a warm engine.

This happens in the blink of an eye as demonstrated at the very end of the video so i slowed it down to count the steps and direction, open and close.

the ecu does not know what position the iacv is at startup , so it always commands the valve open with 65 pulses, it then makes a decision to close x many steps based on the temperature of the eot sensor.

Condensation for a future write-up:
A. IACV opens 65 pulses when ignition on and stop/run in run
B. Cold (any specific ambient range?) IACV then closes 12 pulses for a net opening of 53 pulses.
C. Warm IACV then closes 35 pulses for a net open of 30 pulses.

Questions (for which we may not have data):
1. How many pulses (stepper motor steps) per revolution?
2. How many pulses per linear distance?
3. When stop/run is stopped, does IACV motor close plunger?
4. If so does it fully close?

This certainly provides a very smooth warm-up operation, especially compared to steps on carburetor linkage. It finally got cool enough in Las Vegas valley last week for my 2014 standard to fast idle at 1500 RPMs instead of 1300.

Your information should help all of us better understand IACV operation.
a. Increased air supply increases idle speed and lends to the understanding of why a minor intake vacuum leak would cause increased idle speed.
b. Cycling the stop/run commands the IACV to preposition by open/close movement, which offers one of two (IACV or TPS) likely explanations for Riko's restart in his video.

For basic info on stepper motors, this video explains how it steps:
https://www.youtube.com/watch?v=zK1Y1O7XZes
This is a more sophisticated motor in comparison to the Superior Slo-Syn motors that I sold beginning in 1984.

A stepper is frequently connected to a lead screw to transfer rotary motion to linear motion. Therefore linear travel, in relation to pulses, would be a function of (a) pulses per revolution and (b) screw pitch.

Recent bikes:
2014 Honda CB110 standard (new 7 Nov 2017)
2018 Yamaha XT250
2016 Moto Guzzi V7II
2017 Yamaha TW200
2012 Triumph Bonneville
2002 Harley-Davidson Sportster 1200 Sport
2003 Harley-Davidson Sportster XLH883
(This post was last modified: 12-15-2017 10:04 AM by SportsterDoc.)
12-15-2017 09:32 AM
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pdedse Offline
Running Like a Top

Oregon
Posts: 500
Joined: Dec 2013
Post: #23
RE: Diagnostic Trouble Codes & Sensor testing
(12-15-2017 09:32 AM)SportsterDoc Wrote:  ...

a. Increased air supply increases idle speed and lends to the understanding of why a minor intake vacuum leak would cause increased idle speed. ...

Regarding the above, would a "minor intake vacuum leak" that causes inreased idle speed ocurr no matter the ambient temperature? I ask because of late--the last 5 rides of 1/2 hour to 2 hour duration in cooler temps of 35-55 degrees--the high/low idle issue has not returned since cleaning the TPS connector. The change that coincided with the cleaning was the fall in air temp.

A side note:
I can't help but wonder whether our internet paths crossed when I was on the Sportster forums from 2014-10--I had an '04 1200C.
12-15-2017 11:12 AM
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max Online
1st Service Completed

auckland
Posts: 50
Joined: Sep 2017
Post: #24
RE: Diagnostic Trouble Codes & Sensor testing
Doc, thanks for the better description of the iacv pulses, that makes more sense now.

q3: on shutdown, either with key or stop/run the iacv remains in it's current position, when i switched it off there was just a single blip of the led's indicating it had no time or inclination to close with any command, when it is switched off its instantly dead in the water.

The ignition key switches the dashboard, which has it's own micro controller and translates the signals for the instruments.

The start/stop supplies the Engine Control Module, fuel pump and ignition system and initiates ( resets ) the iacv and ecm every time it's powered on.

So when you hear the fuel pump pressurize cycle the ecm and iacv reset as well and the iacv positions itself according to the engine temp at the time.

Also, when the engine is switched off when warm the iacv remains in the "warm" position, should you disconnect it and start the engine it is likely to start around 1050 rpm ( speculation ) but you get the etc code as well.

q4 no, it remains in the position at switchoff.

There is another video which resembles our iacv and shows what is likely inside it, if you forward to 7.5 minutes in the video he shows the parts on the table and the rotor with a special magnetic "flux sheet" to show how the poles are positioned on the rotor, if you look closely you can see the two sets of stators with their poles that wrap around the two coils that power them.

https://www.youtube.com/watch?v=QIHhDGLx9Lg

cheers max
(This post was last modified: 12-15-2017 12:27 PM by max.)
12-15-2017 12:00 PM
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SportsterDoc Offline
1st Service Completed

southern Nevada
Posts: 214
Joined: Nov 2017
Post: #25
RE: Diagnostic Trouble Codes & Sensor testing
(12-15-2017 11:12 AM)pdedse Wrote:  ...would a "minor intake vacuum leak" that causes inreased idle speed ocurr no matter the ambient temperature? I ask because of late--the last 5 rides of 1/2 hour to 2 hour duration in cooler temps of 35-55 degrees--the high/low idle issue has not returned since cleaning the TPS connector. The change that coincided with the cleaning was the fall in air temp.

Yes, the no idle (without throttle) issue on my V7II first occurred at 8,000 feet, I think in September. It was cured when I tightened the rubber intake manifold band from single throttle body. Thermal expansion may change the leak (larger or smaller). A small leak will increase idle speed, a larger leak will cause motor to not idle. I certainly do not know that a single idle issue on our bikes is due to a vacuum leak, but it is a quick and easy check. Vacuum leaks are a frequent problem on the XLForum.net

(12-15-2017 11:12 AM)pdedse Wrote:  A side note:
I can't help but wonder whether our internet paths crossed when I was on the Sportster forums from 2014-10--I had an '04 1200C.

I posted on Sportster.org from early 2003 until its demise in 2012.
Then I switched to the XLForum.net 24 April 2012 until 2 weeks ago.
I am weaning myself off it, as (a) I kept providing the same answers, (b) technical questions for electrical and carbs dried up, ( c ) two members created Sporsterpedia, which now has a lot of answers

I did respond to one of your threads: http://xlforum.net/vbportal/forums/showt...?t=1493461

(12-15-2017 12:00 PM)max Wrote:  q3: on shutdown, either with key or stop/run the iacv remains in it's current position
q4 no, it remains in the position at switchoff.

Thanks, Max

(12-15-2017 12:00 PM)max Wrote:  There is another video which resembles our iacv and shows what is likely inside it, if you forward to 7.5 minutes in the video he shows the parts on the table and the rotor with a special magnetic "flux sheet" to show how the poles are positioned on the rotor, if you look closely you can see the two sets of stators with their poles that wrap around the two coils that power them.

https://www.youtube.com/watch?v=QIHhDGLx9Lg

Good details, thanks, Max

44 gauge wire is only 0.002". For comparison, I was involved with an automation project using 0.003 "muscle" wire for a diabetic insulin injector pump. That is the typical diameter of a human hair.
[/quote]

Recent bikes:
2014 Honda CB110 standard (new 7 Nov 2017)
2018 Yamaha XT250
2016 Moto Guzzi V7II
2017 Yamaha TW200
2012 Triumph Bonneville
2002 Harley-Davidson Sportster 1200 Sport
2003 Harley-Davidson Sportster XLH883
(This post was last modified: 12-16-2017 08:44 AM by SportsterDoc.)
12-16-2017 08:16 AM
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