Idle issue killing me

I'm about ready to tear my hair out over this. Bike was fine, until about about 3 months ago when it started hesitating on decel. About 3 months prior to all this (around Dec.) I went through and gave it a all around service and had it retuned. At that time air filter was cleaned, fuel filter changed, spark plugs replaced, TPS and ISCV set, AFR optimized on a dyno. (There may have been more done, but that's off the top of my head).

When the hesitation started I figured it was a TPS issue, so that was reset to no avail, it was only off by like 0.01. I know it's been running a little fast, but pulled up TuneECU and see it fires cold at about 1600rpm and settles to 1350-1400 rpm when it warms up. The tune is set to 890rpm. I'm at a loss at where the fault is here.

Thoughts?

Oh, it's a 2015 R3T, and throttle bodies were balanced around 3 months back when everything else was done.

Well everyone says the secondary TPS doesn't control idle at all, but I checked the seconday to find it was about a quarter volt low. Recalibrated it and now the idle seems to want to drop. It'll idle high, then drop down to about the right level for about a second before raising back up. So that's different, but I'm not sure that's progress.

Hello,
Assuming you have the 02 sensor working have you tried the 12 minute tune?

Rick

Have you checked to make sure there is enough free play in the throttle cable ? Have you cleaned the crank position sensor ? It also could be a vacuum leak.
Not sure how you get under the tank on a touring. It raises up on the others models. Once under the tank I would look for cracked or disconnected vacuum hoses or torn intake boots. There are also little rubber caps on the intake side of the throttle bodies that can come off. If everything looks good, get a spray bottle of water and start spraying around under there while it's running and listen for changes in Idle speed. Water works better than starting fluid. If you use starting fluid, eventually enough of the vapor will make it to the air filter and change the idle speed and skew your results.


[NOTE: On US Touring models, most are equipped with the evaporative emission canister, so on the extra vacuum ports of the three throttle bodies there are three vacuum lines that are joined, and run to the canister under the left side cover.]

@m3g - O2 sensor is bypassed and removed.

@Rocket Scientist - throttle cable seems to has sufficient slack. I checked for broken hoses, but didn't use a spray bottle. Great idea! I think I'll probably have to block drippage from the RamAir though.

Having re read the thread I think Rocket Scientist's approach seems like the plan.

When reading this I was wondering about the idle speed control.

Anomaly said:

It'll idle high, then drop down to about the right level for about a second before raising back up. So that's different, but I'm not sure that's progress.

Click to expand...

Being very new to the rocket so take everything here with a grain of salt.

I removed the o2 sensor and disabled it with TuneEcu so I could install a wide band in the same spot to monitor the A/F ratio.
While experimenting with some different tunes and idle / off idle timing I have found the following.
With the timing slightly reduced at idle the bike started fine and ran fine, but would stall when down shifting.
Reconnected the original O2 sensor and ran the 12 minute tune. Re installed the wide band no more stalling.
All seems well.

So then

Went back to original timing now off throttle and the idle went down to around 1,300 - 1,250 then slowly the RPM dropped to where it should be and stays there. (Not exactly fun when doing a U turn in the gravel).

Today if it is raining as it has every weekend since I got the bike I plan on welding a separate bung to mount the wide band and replace the original o2 sensor then run a 12 minute tune again.

If I understand correctly the 12 minute tune only works when the original O2 sensor is working.
Below is just a guess...
If it works similar to other systems during the tune not only is the A/F mixture adjusted but also the "parked" position of the Idle Speed Control. That is the position ISC is in when the bike is running above idle. When the bike is returned to idle it goes there and then the ECU tries to adjust the position to maintain the target RPM. Because the adjustments are small and slow the bike may stall before the ECU can get it to the target RPM or we see the slow decrease in RPM to the target.
That being said it does not explain while in one case yours idled high, then dropped where it should be but then went up again.

Rick

@Anomaly find my old post on this. Its exactly the problem we had with Paul Bryant's bike. Suggest try this:

Lie to the ECU: try setting 0.62 and 0.74. If this doesn't work, reset to 0.60 then note engine temp for idle speed value, start the bike and simply adjust the ISM using the 7 mm nut to the correct idle speed. See how it goes then; it worked for us. Then recheck the new TPS and ISM values: you may be surprised.

Hey, if it doesn't work you can easily put it back. Until yesterday I was still running the original TPS and my bike is 13 years old now.

@sleeves I did look through your post beforehand and to be honest I didn't follow as you guys swapped out half the bike (and then put all the originals back). I wasn't convinced the TPS was what actually what caused the low idle issue.

But you know what... setting the P-TPS to 0.62 and the ISCV to 0.74 fixed it!

I just don't understand how it suddenly changed. Not sure how that happens but it's back up and runnin'. THANKS! If you hadn't suggested it, I wouldn't have tried it.

Anomaly said:

@sleeves I did look through your post beforehand and to be honest I didn't follow as you guys swapped out half the bike (and then put all the originals back). I wasn't convinced the TPS was what actually what caused the low idle issue.

But you know what... setting the P-TPS to 0.62 and the ISCV to 0.74 fixed it!

I just don't understand how it suddenly changed. Not sure how that happens but it's back up and runnin'. THANKS! If you hadn't suggested it, I wouldn't have tried it.

Click to expand...

Hi @Anomaly glad to be of service.

In regard to our post yes we swapped out half the bike and wasted 3 weekends of our lives on what was, in the end, a simple fix. We were kicking ourselves and thought we were smarter than that, live and learn.

The TPS and ISM values do drift as they are electrical components and the small constant adjustments the bike doses wears the area it works in the most. It's my opinion that by altering the values it runs on and telling the ECU it's the design value moves the operating position to an unworn part of the sensor. As per another post I put up today my stock 2005 TPS is now 13 years old and I only changed it last weekend but I suspect it was OK still. I may refit it yet.