04-29-2020, 05:37 AM
My story is similar to anyone who has experienced this problem.
Idle speed drops to 500. Sometimes it increases to 1500.
I was struggling with this for 1 season, around 17000 km.
I didn't have a DTC that pointed to IACV.
Recently, idle was stayed at 1500 and did not want to fall down.
I have read the SM and forum.
I made all possible measurements with an ohmmeter and voltmeter.
Oil temperature sensor OK (EOT), its resistance is in accordance with the service manual, 2.7K ohms at 20 degrees Celsius.
I turned the sensor out and put it in the water I heated.
Its resistance changed once with water temperature changes.
IACV has a resistance of 107 ohms at around 25 celsius cells.
I bought a new IACV. In Poland, it costs around 154 USD.
I compared the resistance of the new and old (still mounted), which was almost identical.
I checked the all the wiring with an ohmmeter (SM)... OK.
There is an ECU under the fuel tank.
I took out the plugs from the ECU and checked for corrosion ... it wasn't ... perfect condition.
Prophylactically, I sprayed ECU plugs (all) against corrosion.
Next to the ECU is a screw screwed into the frame, which provides ground for several electrical components, probably also ECU.
There was patina and slight corrosion.
I cleaned the brass contacts and cleaned the frame which rusted gently in the place which is predicted for contact.
Finally, I assembled tank and wires and went for the ride test.
The problem has not disappeared.
1500 RPM was still on.
After this test, I wanted to remove the plug from IACV again, it was very hard to do that.
I accidentally moved the IACV by turning it 1-2 degrees when I tried to remove the plug.
When I discovered that IACV can be gently shifted, I moved it right and left a few times with the engine running.
At some point, the engine speed dropped from 1500 to 1000 .....UPS !!! sounds like a fairy tale of 7 dwarfs
I understood that I could have a dirty IACV or a chamber in which it is embedded.
The problem stopped ... but not entirely.
Last weekend I went with my daughter on a 400km route.
Twice it happened that idle speed dropped to 500.
Once the engine went out.
I took the motorcycle to the Honda site yesterday and IACV was replaced. (100$ only)
IACV chamber cleaned.
I asked the mechanic if it was easy to pull the IACV out of the chamber.
He replied that it was not so easy.
IACV was sitting quite tightly and it took little strength to pull it out.
I agree with this because I had to use some power to move the IACV with my fingers to the right and left.
Today, I drove 60 km in urban conditions ... using gears 1 - 2 - 3 - 4 - 3 - 1 (everyone knows when the problem occurs).
We'll see what will happen next ... but it looks OK for now
In addition, the motorcycle has more power and stopped smelling gasoline, which happened earlier.
In addition, about 1000km ago examined the state of exhaust gases.
It was bad.
Tomorrow I will check how it is after replacing the IACV.
I have an old IACV. Does not look worn and dirty.
Idle speed drops to 500. Sometimes it increases to 1500.
I was struggling with this for 1 season, around 17000 km.
I didn't have a DTC that pointed to IACV.
Recently, idle was stayed at 1500 and did not want to fall down.
I have read the SM and forum.
I made all possible measurements with an ohmmeter and voltmeter.
Oil temperature sensor OK (EOT), its resistance is in accordance with the service manual, 2.7K ohms at 20 degrees Celsius.
I turned the sensor out and put it in the water I heated.
Its resistance changed once with water temperature changes.
IACV has a resistance of 107 ohms at around 25 celsius cells.
I bought a new IACV. In Poland, it costs around 154 USD.
I compared the resistance of the new and old (still mounted), which was almost identical.
I checked the all the wiring with an ohmmeter (SM)... OK.
There is an ECU under the fuel tank.
I took out the plugs from the ECU and checked for corrosion ... it wasn't ... perfect condition.
Prophylactically, I sprayed ECU plugs (all) against corrosion.
Next to the ECU is a screw screwed into the frame, which provides ground for several electrical components, probably also ECU.
There was patina and slight corrosion.
I cleaned the brass contacts and cleaned the frame which rusted gently in the place which is predicted for contact.
Finally, I assembled tank and wires and went for the ride test.
The problem has not disappeared.
1500 RPM was still on.
After this test, I wanted to remove the plug from IACV again, it was very hard to do that.
I accidentally moved the IACV by turning it 1-2 degrees when I tried to remove the plug.
When I discovered that IACV can be gently shifted, I moved it right and left a few times with the engine running.
At some point, the engine speed dropped from 1500 to 1000 .....UPS !!! sounds like a fairy tale of 7 dwarfs
I understood that I could have a dirty IACV or a chamber in which it is embedded.
The problem stopped ... but not entirely.
Last weekend I went with my daughter on a 400km route.
Twice it happened that idle speed dropped to 500.
Once the engine went out.
I took the motorcycle to the Honda site yesterday and IACV was replaced. (100$ only)
IACV chamber cleaned.
I asked the mechanic if it was easy to pull the IACV out of the chamber.
He replied that it was not so easy.
IACV was sitting quite tightly and it took little strength to pull it out.
I agree with this because I had to use some power to move the IACV with my fingers to the right and left.
Today, I drove 60 km in urban conditions ... using gears 1 - 2 - 3 - 4 - 3 - 1 (everyone knows when the problem occurs).
We'll see what will happen next ... but it looks OK for now
In addition, the motorcycle has more power and stopped smelling gasoline, which happened earlier.
In addition, about 1000km ago examined the state of exhaust gases.
It was bad.
Tomorrow I will check how it is after replacing the IACV.
I have an old IACV. Does not look worn and dirty.