tps evaluating for ii issues

[SportsterDoc]

Thank you to all you great guys who are assisting to solve this problem. I put about 65 miles on the bike yesterday. The slow idle came, and went. Sometimes it is more severe that others, like when the engine was stalling on Saturday; yesterday it was not very severe (it worked back up to a normal idle in about 5 seconds). I listened for the IACV sound yesterday, and there was none. Something else I discovered, turning the bike off with the key and restarting it seems to "temporarily" resolve the low idle issue.

Do I have to remove the entire throttle body assembly from the bike to replace the IACV? I thought this is what the factory service manual said. Does this vale operate by rotating, or by traveling inward and outward?

I will replace my IACV and see if this works. However, my VFR800 is in pieces in the garage because I am rebuild the forks and replacing the steering head bearings, so I have to finish that job first.

Dave, Popgun suggested that about a year ago (CB1100 idle speed stability thread), but before you do, unplug it, clean the connector and re-plug it. Also check for any damage to the wires going into the connector.

For those who replaced the IACV, without success, it may be due to a peripheral issue, such as connector, wiring or obstructed ports controlled by the IACV.

Below was posted 27 Dec (CB1100 idle speed stability thread). You can check off what has been done and what may remain:

Suggestions if you experience low/high idle issues:

1. Check for active codes, per page 5-12 & 5-13 of the Factory Service Manual, checking the codes lists on pages 5-15 & 5-16

2. Check for stored codes, per page 5-14 of the FSM

3. If no codes, then insure that there is no vacuum leak. An unlit propane torch applying propane to intake areas will detect a leak by listening for a change in idle speed. Check vacuum hoses and fittings, one 4 way (17201-MCJ-003, $7) and one 5 way (17201-MCZ-003, $5.60), then snug all 8 clamps from throttle bodies to intake.

A. Disconnect Throttle Position Sensor connector (engine OFF), clean contacts (contact cleaner available at Home Depot or Lowes, etc.), check for damaged wiring and reconnect. GO FOR A RIDE. If issue persists, continue

B. Disconnect Idle Air Control Valve, clean contacts, check for damaged wiring and reconnect. GO FOR A RIDE. If issue persists, continue

C. Follow TPS diagnostics per pages 5-23 thru 5-25 of the FSM. Note comments in posts 615, 618 & 622, especially see Max's post 632 regarding TPS output test in CB1100 idle speed stability thread. If output is not 0.5 VDC, loosen fasteners (ignition on, engine NOT running) and rotate TPS to obtain 0.5 VDC, throttle closed. After adjusting TPS throttle closed output, do a throttle calibration with ignition on, engine NOT running, by SLOWLY opening and closing throttle, 2-3 times. GO FOR A RIDE. If issue persists, continue

D. Follow IACV diagnostics per pages 5-74 & 5-75 of the FSM. If OK, then remove IACV, clean IACV port and check for unobstructed travel. If not OK, IACV (16430-MJF-D01) is $119.13 from Honda. GO FOR A RIDE. If issue persists, continue

E. Follow EOT (Engine Oil Temperature Sensor) diagnostics per 5-21 of FSM, particularly resistance value of 2.4 to 2.9 Kohms (2,400 to 2,900 ohms) at 20C / 68 F. If not OK, EOT sensor (37750-KPH-701) is $34.56 from Honda. GO FOR A RIDE. If issue persists, re-check the FSM diagnostics. Note that a faulty ECM is a possibility, albeit rare. The only time I recall a failed ECM on a Sportster, was due to an internal 5 VDC sensor power supply failure.

The EOT (Engine Oil Temperature) sensor and IACV (idle Air Control Valve) are available from Honda. The Honda Rune Forum has posted a TPS replacement for the Keihin JT6H TPS: 16060-MBZ-A11, $114.29 from honda. This is for a 2006 CB600F. The Rune Forum posted that this sensor is a Keihin JT6H, but we have not yet verified compatability.

For non-USA owners, check that the latest ECM program is installed by your dealer.

The valve works by rotating. Do you have a service manual? Check page 5-74 and 5-75 for a pic.

Be helpful if we had a better quality photo of the air ports. Cleaning the IACV is a common automotive issue and symptoms are similar to the low idle on the CB.

Meanwhile, Max has been coordinating the effort to narrow it down.

1. It does not seem to be a MAP issue, due to symptoms not matching.

2. It does not seem to be an EOT issue, per reports in the CB1100 idle speed stability thread, nor do symptoms match.

3. It does not seem to be a TPS issue, due to the recent testing guided by Max.

4. I remain concerned about a large intermittent vacuum loss, but that possibility seems to have been explored by Popgun's testing, per emails between Max, Popgun, Peter and I. Still would like to hear back from Dave on removing purge hose from purge valve to intake manifold (engine fully warm), to know if idle drops or if plugging it causes idle to return to normal. The effect on one bike may differ from another, perhaps due to carbon build-up, a saturated evap canister, etc.

5. Manual pages 5-74 and 5-75 cover IACV (symptoms seem to match): There is a caution about cleaning before removal to prevent debris in the IACV passage(s)...therefore, any debris would be a concern. Popgun also suggested that any warpage of the plastic intake may interfere with IACV operation. A stepper motor does not provide feedback to programmed movement. A clearance check should be done when replacing.

Note the symptoms/fail safe function of all DTC on pages 5-15 and 5-16 of FSM. Focus on the IACV.

The IACV is 16430-MJF-D01

http://www.2wheelpros.com/oem-parts/2014...mbly.html#

There have been some TPS or TPS wire/connector issues. However, consider this: Each time the entire throttle body assembly was replaced the problem was reported to be cured. This replaced TPS, IACV and provided a clean throttle body (all new vacuum hoses & fittings?), including the IACV port(s). Deduction: TPS checked OK, so what is left?

At this time, if the purge valve is not an issue, I would focus on the IACV, starting with checking the electrical connector. If no joy, then remove and clean IACV passages. Due to the labor involved, probably also replace the IACV...although that would not allow proof that cleaning solved the issue.

For IACV port cleaning, use throttle body cleaner, not carb cleaner, due to contact with plastics.