Another rough running engine

[BaldKnob]

and it has me chasing my tail. Before I start randomly buying new sensors and replacing perfectly good parts, perhaps you experts can point me in the right direction?

Current problem, the engine sputters and spits with acceleration and pops on decel. Starts good, idles and does not stall. But it only acts up when indicated temps are over 180 and seems to get worse into the 200's. Once cooled down, it runs excellent. The stuttering sensation feels like the TC intruding but very harshly. I can pick up speed but need to use the throttle slowly or the whole bike will begin to buck.

Back story, 2012 with 107K miles. New pistons/topend at 76K and it has never ran better. Arrow headers with Akra installed in June and other than some mild surging between 2-3000, I have been loving the rowdy nature of this engine but recent events made me put the stocker back on. It does the same thing but with less sound, power and response. Engine gets hot...it's a buckin' bronco.

So I disconnected the MAP sensor...got an engine light and it ran worse cold or hot (still starts and idles). Connections to the injectors were solid, temp sensor all good. O2 sensors were tight and looked carbon free. New fuel pump this year (my first purchase in this chase OUCH!). New O2 sensors are easily 3 bills...is this my next? I was so hoping the pressure sensor was the culprit and I could just add to Moki's thread rather than start another. Anybody got any clues? I was thinking a new ES would be nice but I just got a Cogents upgrade and a SC seat and it was running so good...

 

[Dogdaze]

As long as you've eliminated bad fuel, may I suggest it could well be coil sticks? They seem to produce the symptoms you describe once engine gets hot.

 

[BaldKnob]

Thanks, Dogdaze, I did replace plugs and filter about 10K miles ago. I assume there is no way to really "check" the coils other than replacing them and hoping for the best? As for fuel...I've been through several tanks of gas and condition remains the same.

 

[Dogdaze]

I would start with the coil sticks, they have been known to arc, especially the right side as they are prone to water ingress. Not entirely sure how to effectively check each one though (someone may chime in) if it was me, I'd start with one and move on from there. Also, at 107k miles, they could well be due..... Good luck ::008::

 

[EricV]

Sounds like you don't have a Factory Service Manual. You also don't mention if you checked for ECU error codes. There are directions on the forum. Sorry I don't have the time to hunt them down this morning or look in my FSM.

Fuel Air Spark. Narrow it down to one, then you can dig into it more. Sounds like you have mostly eliminated Fuel. Did you check the airbox above the filter and the intake snorkle for debris?

There likely is a method by which to test the coil sticks.

 

[BaldKnob]

I would start with the coil sticks, they have been known to arc, especially the right side as they are prone to water ingress. Not entirely sure how to effectively check each one though (someone may chime in) if it was me, I'd start with one and move on from there. Also, at 107k miles, they could well be due..... Good luck ::008::

When I changed the plugs in August, no corrosion noted to the coils or plugs and there were no issues with removing the coils from the sparkplug well.

Sounds like you don't have a Factory Service Manual. You also don't mention if you checked for ECU error codes. There are directions on the forum. Sorry I don't have the time to hunt them down this morning or look in my FSM.

Fuel Air Spark. Narrow it down to one, then you can dig into it more. Sounds like you have mostly eliminated Fuel. Did you check the airbox above the filter and the intake snorkle for debris?

There likely is a method by which to test the coil sticks.

I do have the manual but my search stopped after checking the sensors. I will look see if there is something blocking the air passage and take a look at the plugs this weekend. I noticed code "42" flash on a couple occasions when the CEL has appeared but I've not checked the DIAG in my bikes system for specific codes.

 

[Dogdaze]

Error code 42 usually refers to a wheel sensor........

 

[Crew Chief]

You typically test coils with a resistance check. There is a separate spec for both the primary and secondary side. The manual should specify how to do it.

 

[AdvToorer]

...
Starts good, idles and does not stall. But it only acts up when indicated temps are over 180 and seems to get worse into the 200's. Once cooled down, it runs excellent. The stuttering sensation feels like the TC intruding but very harshly. I can pick up speed but need to use the throttle slowly or the whole bike will begin to buck.
...

I'm not familiar with the mechanics of the enrichment circuit but sounds like it's not being disabled once engine reaches temperature.

 

[2daMax]

If it only starts acting up after tick over (warmed up), then the following Close Loop devices will be suspect, MAP (pressure) sensor, intake air temp sensor, O2 sensor.

I have known a case where the MAP sensor hose was kinked/collapsed causing similar issues. Try a new hose (a short term substitute would be the 4mm ID clear hose from a aquarium shop). I would also look for vacuum leaks, at RHS TB barb rubber plug, and the 2 Boots that connects the TB to the Air Intake Box.

The TPS seems to be a suspect too but am not sure if the TPS signals are monitored/considered by the ECU once ticked over.

lastly, check if anything is obstructing the air intake box. Could be squirrels trying to find a nest for the nuts and keep warm.

 

[BaldKnob]

Thanks for the suggestions and, of course, I should have went straight to the manual. I found my multimeter and have a rainy day tomorrow. I'll start with the coils and go from there. Highly doubt the squirrels have settled as it continues to act normal when temps are low. I'm beginning the suspect this is the "Cascade" phenomena of high mileage machines because the ABS unit failed last month and I lost a diode on one of my Cyclops H7 bulb. The struggle is real.

 

[Checkswrecks]

Thanks for the suggestions and, of course, I should have went straight to the manual. I found my multimeter and have a rainy day tomorrow. I'll start with the coils and go from there. Highly doubt the squirrels have settled as it continues to act normal when temps are low. I'm beginning the suspect this is the "Cascade" phenomena of high mileage machines because the ABS unit failed last month and I lost a diode on one of my Cyclops H7 bulb. The struggle is real.

Start by cleaning every electrical connection in the charge circuit and the ground points. It doesn't take much resistance in either to induce whacky symptoms.

 

[BaldKnob]

You typically test coils with a resistance check. There is a separate spec for both the primary and secondary side. The manual should specify how to do it.

Done and dun. All four coils had higher primary resistance (1.8-2.0) with 2ndary levels in spec. Pricing around about $104 each at Babbitt's. Ouch.

 

[dcstrom]

At around that mileage I had one bad coil - the right one. Your symptoms sound similar to mine. I was lucky, a bit of sponsorship from Yamaha meant they replaced all 4. If I'd been paying myself I would have just replaced the right side one to see if that fixed the problem. If you can find a way to test them, that's probably the best thing.

Oh OK I see you did the test All bad then? It's possible mine were too then, and that info got lost in translation from the German techs that worked on it.

 

[dcstrom]

Baldknob, here's my write-up on things checked or replaced at my 100,000 mile service. You might find something interesting in there...
https://www.facebook.com/aroadanywhere/posts/541006699394253

 

[BaldKnob]

Update on the coil sticks...replaced all 4 and buttoned it up (that airbox breather tube is ridiculous) to an instant start and good idle. It's 40 degrees outside. ABS light still on. Then check engine followed by TC light and 42 flashing in the dash. Still idles but doesn't want to take throttle until temps reach 150. Fan comes on and I shut it down to cycle the ignition. Restart and the TC/CEL appears but goes out in the first mile. Normal throttle even when temps were reading 200+. I only got 20 miles in but feel hopeful that this was my problem. We shall see.

Thanks for the replies and thanks Trevor for the link to your travels. It's great riding along with you and seeing you put the Tenere thru hell and back. Ride on.

 

[SilverBullet]

Update on the coil sticks...replaced all 4 and buttoned it up (that airbox breather tube is ridiculous)...

Next time remove breather tube at valve cover only, not at airbox. 10x easier to get back together.

_

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