[Ev03]

Hello, I own a 2006 GSXR 1000 with 21k miles and I’m having some trouble. The bike has a mildly rough idle I mean like a 100-200rpm flutter and I can hear the bike stuttering at idle. At first I tried to adjust the idle assuming it just needed to be adjust, didn’t fix it. I then tried some trouble shooting, I made sure that the coils were completely plugged in, the air filter was not dirty and everything was plugged in. I had a spare ecu from the same year swapped it didn’t change anything (I had a flashed one in it). This is were things get interesting, there are 2 plugs on the air box a green one, larger and closer to the right side of the bike and a smaller blue one closest too the throttle cable/idle screws. Upon disconnecting the blue one (part number 15620-29G00 on the airbox diagram) the idle issue goes away and sounds much better. The bike is not throwing any codes until I unplug that blue sensor and I believe I have found the issue does anyone have any advice on further diagnosing it so I know what to replace?

 

[BillV]

The green connector is for the air intake temperature sensor and the blue is for the intake air pressure sensor. Both sensors are on the airbox but that's just a convenient mounting point for the IAPS. It's actually measuring pressure in the throttle body, as is seen by the hose that runs from the sensor to a manifold of hoses the connect to the throttle body Disconnecting the blue connector should produce a C13 error. You'll also enter fail-safe/limp home mode and the ECM will treat the pressure as 1 atm. That will result in the fuel mixture being richened. If richening the mixture smooths things out, you probably have an air leak somewhere around the throttle body that is producing a lean mixture. That could be at the hoses (seven), the T-fittings (three), or the connections to the throttle body. See 10-8 in the service manual for other possibilities, notably out of spec valve clearances or an unbalanced throttle body.

P.S. The IAPS is a PIA to remove. I made a 2007 inspired modified mount that is shown here. It greatly simplifies things.

P.P.S. I also have something here about reworking the clamps that attach the airbox to the throttle body. The leads to the injectors creates a lot of clutter in the area where the clamp tightening screws are, making them another PIA to get to. That can be greatly simplified. Finally the center screw for the airbox top sits in a well making it hard to engage with a screwdriver. I wrapped masking tape around the shaft of a Phillips screwdriver until the tape was slightly smaller than the well ID (maybe 3/4"). This keeps the screwdriver centered in the well and makes it much easier to engage the screw head. The tape roll just slides up on the screwdriver when not needed.

 

[Ev03]

The green connector is for the air intake temperature sensor and the blue is for the intake air pressure sensor. Both sensors are on the airbox but that's just a convenient mounting point for the IAPS. It's actually measuring pressure in the throttle body, as is seen by the hose that runs from the sensor to a manifold of hoses the connect to the throttle body Disconnecting the blue connector should produce a C13 error. You'll also enter fail-safe/limp home mode and the ECM will treat the pressure as 1 atm. That will result in the fuel mixture being richened. If richening the mixture smooths things out, you probably have an air leak somewhere around the throttle body that is producing a lean mixture. That could be the hoses (seven), the T-fittings (three), or the connections to the throttle body. See 10-8 in the service manual for other possibilities, notably out of spec valve clearances or an unbalanced throttle body.

P.S. The IAPS is a PIA to remove. I made a 2007 inspired modified mount that is shown here. It greatly simplifies things.

It could be the hoses as when one time when I was removing the air box it pulled the longer hose that goes to the set of hoses and plastic fittings that’s connect to the throttle bodies, I will the hoses later today, taking the gas tank off so I can really get a good look, if all the hoses are good I’ll perform a compression test and I assuming that will show if it has some sort of compression leak either on the rings or seats.

 

[Beairsto Racing]

Confirm that you don't have any air leaks, as Bill has suggested.

Compression test only tells you the cylinder pressure.
A leak down test helps you troubleshoot poor compression, pinpointing whether it's top end (valves) or bottom end (piston rings).

When were the valve clearances last checked?

 

[Ev03]

Confirm that you don't have any air leaks, as Bill has suggested.

Compression test only tells you the cylinder pressure.
A leak down test helps you troubleshoot poor compression, pinpointing whether it's top end (valves) or bottom end (piston rings).

When were the valve clearances last checked?

They were checked at 18k, when I bought the bike. When the season ends I will most likely check them again cause of this

 

[Ev03]

I followed all the hoses coming of iaps, the one with the blue connector. I found one of the black plastic joints in between the hoses to not be fully seated. Seemed to help a bit any other ideas? I got a video of it idling and it seems a bit better

 

[Ev03]

The green connector is for the air intake temperature sensor and the blue is for the intake air pressure sensor. Both sensors are on the airbox but that's just a convenient mounting point for the IAPS. It's actually measuring pressure in the throttle body, as is seen by the hose that runs from the sensor to a manifold of hoses the connect to the throttle body Disconnecting the blue connector should produce a C13 error. You'll also enter fail-safe/limp home mode and the ECM will treat the pressure as 1 atm. That will result in the fuel mixture being richened. If richening the mixture smooths things out, you probably have an air leak somewhere around the throttle body that is producing a lean mixture. That could be at the hoses (seven), the T-fittings (three), or the connections to the throttle body. See 10-8 in the service manual for other possibilities, notably out of spec valve clearances or an unbalanced throttle body.

P.S. The IAPS is a PIA to remove. I made a 2007 inspired modified mount that is shown here. It greatly simplifies things.

P.S. I also have something here about reworking the clamps that attach the airbox to the throttle body. The leads to the injectors creates a lot of clutter in the area where the clamp tightening screws are, making them another PIA to get to. That can be greatly simplified. Finally the center screw for the airbox top sits in a well making it hard to engage with a screwdriver. I wrapped masking tape around the shaft of a Phillips screwdriver until the tape was slightly smaller than the well ID (maybe 3/4"). This keeps the screwdriver centered in the well and makes it much easier to engage the screw head. The tape just slides up on the screwdriver when not needed.

I checked all the small hoses coming off the iaps/ one with the blue connector. Found one hose that was not fully seated onto one of those plastic joints. Seemed to help a bit but not marginally but better. Any other ideas?