2009 EFI Suddenly starts to shudder at cruising speed during my trip. (Resolved)

[Monte Webster]

Hello,
I am looking for help from any EFI owners that may have experienced or heard of this situation.

I was on a 3-day, 700 mile trip in the deserts of Southern Utah, Nevada, and CA last week. On the last day, my bike started to behave badly. It shudders when trying to hold a steady cruising speed in the 2200-2500 rpm area. The power drops and speed also. If I twist the throttle quickly a bit, it will power back up and accelerate again, but I can't hold it at a cruising speed for any length of time before it starts to shake again. The condition appeared suddenly and it is not intermittent. My gas mileage plummeted from 48 to 32 mph after this started happening, so fuel is not being burned efficiently. I checked all the visible hoses, battery, and electrical connections that I could get to, but nothing looked wrong.

I was able to get the bike back home, and I have not torn it apart yet. There are about 14,000 miles on this bike and 7000 new since last spring. I put a Freedom Performance 2-into-1 exhaust on about 800 miles ago and have not had any issues until now. All fluids and spark plugs are new within the last year. There is no engine light on.

I am not sure where to start troubleshooting.

Electrical issue: coil pack? O2 sensors? Throttle position sensor?

Fuel issue: Fuel Pressure Regulator? Pressure Sensor?

Other ideas on what to check?

I can test some of these items, like TPS, but I am not sure how to test some of the others to rule them out. How do I confirm FPR and O2 sensors work correctly?

[Lug Nut]

First you have any kind of fuel processor or extra computer on the bike? Secondly did you reuse your stock O2 sensor ended up plug in to your stock harness without any adapter? You could check your TPS voltage to see if it's within specification, it would be unusual for the TPS to go out but it has been known to happen on rare occasion.The stock system had 2 02 sensors Do you have 2 02 sensors on your new exhaust? Are you using a oxygen sensor simulator in place of a sensor by chance?.

I would say it would be most likely an O2 sensor issue, next TPS issue. Very first thing though if it has an aftermarket fuel processor/power commander box I would just simply remove it

[Monte Webster]

Thanks.
There are no aftermarket electronic controllers on the bike. I did re-use the oem O2 sensors and just put them in the new exhaust, so they plugged into the original connectors. I had to lengthen one connector a bit, but it was working fine until now.
I will be testing the TPS when I get a chance. I will also be looking for vac line leaks, etc.

Lug Nut: Did you ever get your shuddering issue solved? If so, what was it?

[Brad_G]

I'm not an expert in this area by any means. But from what I've read the system changes from closed loop to open loop in regards to the O2 sensors depending on throttle. So from your description, I'd check your work where you lengthened the connection. The fact you can change the bikes behavior by rolling on the throttle would make me think fuel delivery (from a pump/regulator perspective) isn't the issue.

[Lug Nut]

I had a power commander V on mine that I went back to the factory tune and just use it for Revlimeter. The weird thing is when I had oxygen sensor eliminators the bike ran good but had that occassional flutter. I got rid of that exhaust I had and got freedom Combat two into one and decided to go ahead and use oxygen sensors again and had to use an extender. Bought brand new 02 sensors. All seemed fine and then once or twice it did the same flutter thing at a stable 70 to 80 mph as soon as you gave it throttle it cleared itself out perfect. It was so odd. I replaced my TPS even though the original one tested out fine. I set the TPS exact in the middle of specification. And since doing everything only one time did it act funny with that flutter even when trying to induce it. Not sure what it is but perhaps the lengthening of the O2 sensor wire? But I put 2000 miles on the bike after doing the work and did not have the issue again.

I would use a voltmeter to see where your TPS is at. And I would take a good look at your wire harness extension maybe unplug it clean the connectors really good with a toothbrush and CRC electrical cleaner. Make sure there's no brakes and any wires or anything. I would then probably disconnect the battery for a few minutes reconnect it go out and ride. Maybe have it go through a relearn. Also go through your diagnostics on your dash and see if there's any stored codes.

[Shores]

When I added true duals on my fuelie, one of the O2 sensor wires was a little short but rather than add an extender I merely pulled it out of the wiring harness cover to make it reach. Maybe you can do that and get rid of your extender.

[Brad_G]

Did you have to cut the outside of the harness? Just curious. I'm going to be putting Freedom duals on my '08 here very soon and just wondered what I'm up against. Thanks!

[Shores]

Did you have to cut the outside of the harness? Just curious. I'm going to be putting Freedom duals on my '08 here very soon and just wondered what I'm up against. Thanks!

I don't remember if I cut the plastic conduit or whether it was already split and I just pulled the wire through the split. Don't let the plastic conduit prevent you from running the wire where you need to. You can always add additional conduit if needed.

[brianmac]

i had a girlfriend that did that too

[Monte Webster]

I am posting this resolution in case this helps someone else with this issue.

I tested the TPS and it was operating in the normal voltage range and seemed to sweep smoothly with the throttle.

I looked for loose or damaged hoses, vac leaks, etc., but found no smoking gun.

I pulled all the plugs and they had normal coloration.

I bought one new O2 sensor to start testing if one was bad. They are so expensive. It's rediculous. When the part arrived, I replaced the lower of the 2 sensors and then went for a test drive. The hesitation/stuttering was GONE! I have ridden every day for a couple weeks now, and taken a few longer rides, and the stuttering has not returned. I must assume that I found the bad sensor. The question now, of course, if why would this one die? The bike only had 14K miles on it. The new muffler was on for 500+ miles. Is that causing this issue? Will this continue to happen?
Well, for now I am just happy to have found the issue. I guess I will need to carry an extra one with me on future trips.

[Brad_G]

Monte Webster you would think if one was defective it would throw a fault code. Unfortunately the service manual doesn't specify any way to test the sensor to see if it's out of range. Hopefully this anomaly is the culprit to your issue and you have many smooth riding miles ahead.

[Lug Nut]

Monte Webster you would think if one was defective it would throw a fault code. Unfortunately the service manual doesn't specify any way to test the sensor to see if it's out of range. Hopefully this anomaly is the culprit to your issue and you have many smooth riding miles ahead.

The O2 sensors have a really weird spec range they operated in sometimes at least in cars. May not always show up on a fault code but will give a little stutter when cruising steady speeds.