Crazy Terra - Expert answer needed

[Mark_H]

I understand this has been discussed in other threads but here is a very strange Terra that even I cannot answer why it is doing this.

Two of us recently undertook a fairly long ride on identical Terras, both with the same mileage 4500 km and the same modifications.
Bikes have the latest software issue 8543016 and have not been updated by the recall because we do not have the privilege of that or any dealer facility here in Philippines.

Modifications are : K&N Air Filter, Booster Plug, Bigger 154 Injector, Brisk Spark Plugs, Cannister removed, O2 sensor disconnected, Decat Exhaust.

The 2 bikes have been treated exactly the same. Everything including Fuel adaptations were reset on the Gs-911 then the bikes were run with the O2 sensor connected for about 100 miles then it was disconnected. They have run faultlessly with absolutely no stalling for almost 2000 miles in all terrains and conditions.

Just over half way through a 600 mile ride in the mountains of Luzon, whilst preparing to leave the hotel after an overnight stop. one of the bikes started to play up whilst the other remained perfect.
At first we put it down to bad fuel because I stopped at a different gas station to the other guy, but having run two more full tanks of fuel through the bike it is still behaving the same.

It will idle erratically then if the throttle is blipped it will hunt between 1500 and 3000 revs all on its own.
If stopped whilst doing this, then immediately started it will rev up to 7000 rpm and remain there for 20 seconds then drop to the hunting between 1500 and 3000.
If stopped a second time it will start and idle perfectly and it will run perfectly all day long.
Next time started after a break, it will go through the whole process again.

We checked everything, suspecting a possible air leak on the throttle body where the cannister was removed, but everything was normal.

We managed to complete the final 250 miles and get the bike home. It actually ran very well except when first started after any break of more than 5 minutes.

Suspecting Idle Actuator or Throttle Position Sensor problems we put the bike on the GS-911 and it showed no relevant fault codes.

We reset/recalibrated the Idle Actuator and the Throttle Position Sensor but it has made no difference, the bike is still doing exactly the same.

When the bike is revving up to 7000 rpm we found it has power and can pull away and run which indicates correct air fuel mixture etc. The same when it is hunting it can be ridden and will pull uphill etc.

So....where is the bike getting the fuel and air from to allow it to rev to 7000 rpm, what is causing it to hunt if the Idle Actuator is working correctly?

Next idea is to reset the Adaptations and go back to square one.
If this does not work, then we will swap out the Idle Actuator and TPS to the other bike, but that is a big job.

If anyone has any experience of the same issue or any better ideas, input will be highly appreciated

Cheers MH

 

[jodie]

happened to me.. almost the same symptoms except for the idling and 7000rpm.

it was a slightly loose battery connection... thought it was dirty or low octane fuel..

 

[Mark_H]

The bike is fixed but I still have no idea why it occurred.

Having disconnected the Booster Plug, performed a full adaptation reset with the O2 Sensor reconnected the bike has been ridden 150 km with no problems at all. The O2 sensor is once again disconnected and the Booster Plug reinstalled.
Once again the bike runs perfectly with no stalls or issues.

Questions still remain....

What caused only one bike to do this when both identical bikes were on the same run in the same place?
How did it rev to 7000 rpm with the throttle butterfly closed?
How did it have power and able to run in gear with the throttle closed?

How crazy is this ECU that it can get these spurious signals and cause these erratic behaviours and why?

 

[mag00]

The bike is fixed but I still have no idea why it occurred.

Having disconnected the Booster Plug, performed a full adaptation reset with the O2 Sensor reconnected the bike has been ridden 150 km with no problems at all. The O2 sensor is once again disconnected and the Booster Plug reinstalled.
Once again the bike runs perfectly with no stalls or issues.

Questions still remain....

What caused only one bike to do this when both identical bikes were on the same run in the same place?
How did it rev to 7000 rpm with the throttle butterfly closed?
How did it have power and able to run in gear with the throttle closed?

How crazy is this ECU that it can get these spurious signals and cause these erratic behaviours and why?

It cannot rev to 7k rpm with throttle body closed. Check your cables for binding. Maybe a shorted something to the speedo/tach that would have the tach indicate a false reading.

There is no temporary or permanent vacuum leak that can allow enough air to run at 7k rpm. The butterfly MUST open for that amount of air for the RPM indicated.

 

[Mark_H]

It cannot rev to 7k rpm with throttle body closed. Check your cables for binding. Maybe a shorted something to the speedo/tach that would have the tach indicate a false reading.

There is no temporary or permanent vacuum leak that can allow enough air to run at 7k rpm. The butterfly MUST open for that amount of air for the RPM indicated.

That is the question I cannot answer.
No cables were binding. Throttle was physically checked as closed. The revs were real, not just indicated. See the video.
No adjustments have been made, only electronic reset of ECU adaptations and it has fixed the fault.

 

[duibhceK]

That is the question I cannot answer.
No cables were binding. Throttle was physically checked as closed. The revs were real, not just indicated. See the video.
No adjustments have been made, only electronic reset of ECU adaptations and it has fixed the fault.

I agree with Mag00. The engine cannot reach 7000rpm unless the butterfly is open very far. There's only 2 things that can cause it to open, the cable or teh Idle actuator.
I'm not sure the actuator has enough reach to open the valve that far, but definitely worth a check.
On the other hand, even with the throttle closed, the valve can still be stuck in an open position. The TR does not have a return throttle cable, so you're not pulling the throttle valve closed, only relying on the spring at the valve side. If anything is preventing the throttle valve from returning to the closed position (dirt, other cables running around that area, ...) closing the throttle would just create slack at the valve side. You probably wouldn't notice when closing the throttle, but there would be noticeably more slack when re-opening the throttle.

But given the very uneven idle at the beginning of your video it's probably the idle actuator opening the valve. So either there's a problem with the actuator itself or with the 02 or AIT sensors which control the Idle Actuator. In your case it might also be the booster plug. A GS911 might indeed tell you more.

 

[mag00]

How is the cable free play? Everything mentioned just smells like a sticky throttle. Did anything get into the intake that could temporarily bind it? Some cloth thread or so, could slow things down a bit.

Put a pair of fresh eyes on it. Might see something new.

Where I worked years ago, they decided to do a tuneup on the delivery truck. New plugs, wires, cap, rotor. Nothing complicated. 6 hours later they came to me for help. Could not get it to fire, checked everything, not just one person either.

I walked out to the truck, saw the rotor sitting on the fender well, picked it up and handed it to them.

OOOPS.

Nothing is as hidden as in plain sight.

 

[Mark_H]

I agree with Mag00. The engine cannot reach 7000rpm unless the butterfly is open very far. There's only 2 things that can cause it to open, the cable or teh Idle actuator.
I'm not sure the actuator has enough reach to open the valve that far, but definitely worth a check.
On the other hand, even with the throttle closed, the valve can still be stuck in an open position. The TR does not have a return throttle cable, so you're not pulling the throttle valve closed, only relying on the spring at the valve side. If anything is preventing the throttle valve from returning to the closed position (dirt, other cables running around that area, ...) closing the throttle would just create slack at the valve side. You probably wouldn't notice when closing the throttle, but there would be noticeably more slack when re-opening the throttle.

But given the very uneven idle at the beginning of your video it's probably the idle actuator opening the valve. So either there's a problem with the actuator itself or with the 02 or AIT sensors which control the Idle Actuator. In your case it might also be the booster plug. A GS911 might indeed tell you more.

The throttle action was inspected with covers off and was normal. It was closing on the spring and there was no cable slack.
Saying that the engine cannot reach 7k rpm with the Throttle butterfly closed is incorrect because it did exactly that.

The bike ran normally until stopped for about 10 minutes or so then when started it would rev up to 7k rpm for about 20 seconds then suddenly drop and hunt from 1500 to 3000 rpm all without touching the throttle at all.
If stopped a second time and restarted it ran normally and idled perfectly again without touching the throttle.
The bike could be ridden normally, in fact it covered 200 miles of mountain roads including various stops etc, there was no Throttle cable issue.

The fault was definitely electronic and not a simple mechanical cable fault.
Proven by the fact that an adaptation reset fixed it.

 

[mag00]

Other things than a cable can cause sticking. Since it seems fixed, how do you propose to satisfy your curiosity?

What is the chirp in the surging just as it hits the higher rpm and drops? That chirp is erratic at idle, by synchronizes with the surge when the surge starts.

What is the double clunk just prior to making it surge? (@14 seconds)

Do you still have the canister hooked up?

 

[Mark_H]

Other things than a cable can cause sticking. Since it seems fixed, how do you propose to satisfy your curiosity?

That is the question. It was fixed and has remained fixed with no mechanical intervention, only an electronic reset of the ECU using the Gs-911.
Initial reset/recalibration of the Idle Actuator and Throttle Position Sensor did nothing, the fuel adaptation reset fixed it.
The really strange thing is with both bikes absolutely identical and being ridden on the same route, why did this one go wrong electronically and the other remain perfect. The only difference was the tank of gas immediately prior to this fault occurring. One bike was fuelled at a different place.

What is the chirp in the surging just as it hits the higher rpm and drops? That chirp is erratic at idle, by synchronizes with the surge when the surge starts.

The 'chirp' is normal on a Terra with the Exhaust Spark Arrestors in place, they all do it on the overrun with throttle closed.

What is the double clunk just prior to making it surge? (@14 seconds)

The 'double clunk' is a small backfire which it did when idling. It also did this backfire occasionally when riding home but it disappeared after the next tank of good fuel. Strange that the backfire disappeared but the erratic idle and revving to 7k rpm remained.

Do you still have the canister hooked up?

Modifications are : K&N Air Filter, Booster Plug, Bigger 154 Injector, Brisk Spark Plugs, Cannister removed, O2 sensor disconnected, Decat Exhaust.

Summing up, my theory is that it has to be the fuel that caused the bike to do this.

Reasons are -
This bike was fuelled at a different gas station to the other.
About 80 km after filling up it stalled and started to run bad and did this strange erratic revving at start up with backfire etc.
It used 12.6 ltrs of fuel over the same distance that the other bike used only 11.1 litres because it had to be ridden harder due to lack of power.
When refuelled with new gasoline it ran better but still had the erratic behaviour at start up even 2 full gas tanks later.
Idle Actuator and TPS reset failed to fix it but Fuelling Adaptation reset did.
No mechanical intervention has been carried out, therefore it was not the throttle sticking etc.

I just wonder if anyone has had bad fuel experiences or knows how bad fuel can have such a dramatic effect on ECU settings.

 

[mag00]

The throttle action was inspected with covers off and was normal. It was closing on the spring and there was no cable slack.

You have to have slack in the adjustment. Random positions of the handlebar can open the throttle otherwise.

It is best to remove the cable and lube it good, and check for any sticky spots. Twist the cable, (direction of tightening the twist of the cable) to check for any irregularities. Then, make sure there is free play at the throttle.

 

[Mark_H]

You have to have slack in the adjustment. Random positions of the handlebar can open the throttle otherwise.

It is best to remove the cable and lube it good, and check for any sticky spots. Twist the cable, (direction of tightening the twist of the cable) to check for any irregularities. Then, make sure there is free play at the throttle.

Maybe I should have said there was no 'abnormal or excessive cable slack or tightness' the bike behaved the same whatever the position of the handlebars.
This fault was nothing to do with simple throttle cable issues - everything was checked and found normal - no mechanical intervention was made - the fault was fixed 'electronically'
Believe it or not the bike did rev up to 7k rpm with the throttle butterfly closed and on its stop !!! It also hunted between 1500 and 3k rpm with the throttle closed and untouched.
How and why it did it is the big question.

 

[duibhceK]

I don't think anyone is saying it cannot have been caused by an electronic fault. But having an engine rev at 7000rpm requires a lot of air for the combustion. That air needs to be physically able to enter the engine. Either through the throttle body or through a serious air leak behind the TB. Since the problem is now solved an air leak is very unlikely so the air must have passed through the TB. The only things that can operate the butterfly valve to let through all that air are the throttle cable and the idle actuator. Since the TR is nor ride-by-wire the only item which electronically operates the valve is the idle actuator.

 

[CarstenB]

i don't see how the idle actuator could operate the butterfly.

 

[duibhceK]

i don't see how the idle actuator could operate the butterfly.

There's 2 ways an Idle Air Actuator works, either by operating the valve, or by opening and closing a bypass channel. I haven't actually looked at which one the TR uses, but whichever it is, imho it is the only part which can provide the additional airflow and is electronically controlled.

 

[CarstenB]

from what i can see it regulates the bypass channel but is not connected to the butterfly. I agree that the idle actuator is the most likely culprit here.

 

[PaulC]

Did yous ride threw much water?

 

[Mark_H]

Did yous ride threw much water?

The bike was ridden through some water, fairly deep puddles but nothing that would have affected the air intake or electrics. We did check for evidence of water ingress but nothing was found.

 

[Mark_H]

from what i can see it regulates the bypass channel but is not connected to the butterfly. I agree that the idle actuator is the most likely culprit here.

The Idle Actuator was my first 'guess' but it was reset/recalibrated along with the TPS but the fault still remained.
Only when a full Adaptation reset was performed did the fault disappear and the bike has run normally ever since.

 

[jodie]

how does one do the adaptation reset?