02-19-2018, 09:31 AM
Well done, Max!
I got involved in this issue late, with focus on vacuum leak, poor connections, TPS and IACV.
Which is why the 27 Dec summary was in this order:
check codes (active and stored)
check for vacuum loss (minor = high idle, major = close to stalling/stalling)
check TPS (FSM symptom/fail safe: hard to start cold)
check IACV (FSM symptom/fail safe: engine stalls, hard to start, rough idle
check EOT (FSM symptom/fail safe: poor acceleration) symptoms did not match, but it was a concern, earlier.
No concern about MAP or IAT, as symptoms did not match.
I was ready to move on from TPS testing before MAX test's were complete, but did not want to interfere with completion of those tests...plus a lot of distractions, last week.
And, if IACV replacement is not an immediate cure, at least the TPS testing was thorough AND we all got an education.
Also, there may have been more than one issue, although the FSM would lead basic diagnostics to the IACV, per FSM pages 5-15 & 5-16.
There is still a possibility of a poor connection in the connector, damage to the wires into the IACV connector or the stepper motor driven "piston" not moving freely.
DTC 29-1, FSM page 5-16, lists IACV circuit malfunction as "loose or poor contact of IACV connector, IACV or its circuit malfunction". The piston not moving as much as the stepper steps would not likely provide a DTC (opinion)
Max pointed out the alignment pin, which prevents the piston from rotating when the motor drives it in and out.
When the IACV is replaced, it would be prudent to well clean the piston port, port air passages and maybe even spray with a shot of silicone lubricant.
4624 miles on my 2014 CB1100 standard in <3 1/2 months.
No issues.
I do not abuse it (easy on throttle until engine comes up to temp, then after warm, rarely over 6,500 RPMs, never bumped the rev limiter), but it does not accumulate cobwebs.
Spark plugs look like new.
Typical MPG is 48-54, as good as my 2016 Moto Guxxi V7II, 744cc!
Worst instant MPG was 24.something, accelerating from 70 to 110 in 6th gear, ~2% uphill grade.
Most trips are about 51-52 MPG
I remain extremely pleased with it.
Stock other than Dart Martin flyscreen, air intake mod, LED tail/brake light and just replaced license plate bracket with a lay-down 4" x 7" stainless steel plate. Saved the cardboard template, should anyone else be interested.
I got involved in this issue late, with focus on vacuum leak, poor connections, TPS and IACV.
Which is why the 27 Dec summary was in this order:
check codes (active and stored)
check for vacuum loss (minor = high idle, major = close to stalling/stalling)
check TPS (FSM symptom/fail safe: hard to start cold)
check IACV (FSM symptom/fail safe: engine stalls, hard to start, rough idle
check EOT (FSM symptom/fail safe: poor acceleration) symptoms did not match, but it was a concern, earlier.
No concern about MAP or IAT, as symptoms did not match.
I was ready to move on from TPS testing before MAX test's were complete, but did not want to interfere with completion of those tests...plus a lot of distractions, last week.
And, if IACV replacement is not an immediate cure, at least the TPS testing was thorough AND we all got an education.
Also, there may have been more than one issue, although the FSM would lead basic diagnostics to the IACV, per FSM pages 5-15 & 5-16.
There is still a possibility of a poor connection in the connector, damage to the wires into the IACV connector or the stepper motor driven "piston" not moving freely.
DTC 29-1, FSM page 5-16, lists IACV circuit malfunction as "loose or poor contact of IACV connector, IACV or its circuit malfunction". The piston not moving as much as the stepper steps would not likely provide a DTC (opinion)
Max pointed out the alignment pin, which prevents the piston from rotating when the motor drives it in and out.
When the IACV is replaced, it would be prudent to well clean the piston port, port air passages and maybe even spray with a shot of silicone lubricant.
4624 miles on my 2014 CB1100 standard in <3 1/2 months.
No issues.
I do not abuse it (easy on throttle until engine comes up to temp, then after warm, rarely over 6,500 RPMs, never bumped the rev limiter), but it does not accumulate cobwebs.
Spark plugs look like new.
Typical MPG is 48-54, as good as my 2016 Moto Guxxi V7II, 744cc!
Worst instant MPG was 24.something, accelerating from 70 to 110 in 6th gear, ~2% uphill grade.
Most trips are about 51-52 MPG
I remain extremely pleased with it.
Stock other than Dart Martin flyscreen, air intake mod, LED tail/brake light and just replaced license plate bracket with a lay-down 4" x 7" stainless steel plate. Saved the cardboard template, should anyone else be interested.