Rough idle and ECU codes 11 & 12

[jblanken64]

I've done quite a bit of forum searching already, but haven't found a definitive answer yet.

A little over a month ago, my bike (2008) developed a rough idle once warmed up. I've run Sea Foam, and injector cleaner through it, changed to premium gas and non-ethanol gas, changed the oil (because it was time anyway), changed the plugs, and inspected a bunch of connectors so far (focused on ECU connector since I've read that some corrosion can develop). I've run a bunch of the ECU diags and everything seems right, particularly the TPS which was initially assumed to be a possible culprit. Even though the check engine light has never come on, last night I noticed that codes 11 and 12 are in the ECU. Those are cylinder ID sensor and crankshaft position sensor failures. I didn't have time last night to track down those particular sensors to check the connections and ohm them, but maybe this evening I'll get to that.

Any other ideas? I've read that everything from a bad battery to dirty injectors can cause this type of symptom, but for every post ID'ing a cause someone else discounts it. The bike has been bulletproof until just recently. The local Yamaha shop didn't have any concrete advice other that the path I'm currently taking. They said they never have to work on FJR's outside of tires and fork seals.

Thanks in advance,

Joey.

 

[RossKean]

Throttle body synchronization and set idle speed ~1100. As far as the ECU codes are concerned. Reset them and see if they return. If they do, you should investigate further. How many miles on the bike?

 

[RaYzerman19]

It may be related to the work you just did....... You may have turned the key on while these sensors were disconnected. That will definitely set the cylinder identification sensor fault. Like Ross says, clear them and see if they return. As for the rough idle, there may be a bad connection of the spark plug wire to the plug adapter..... unscrew them, trim off 1/4" or so, spread the strands evenly and screw the adapters back on.

 

[RossKean]

It may be related to the work you just did....... You may have turned the key on while these sensors were disconnected. That will definitely set the cylinder identification sensor fault. Like Ross says, clear them and see if they return. As for the rough idle, there may be a bad connection of the spark plug wire to the plug adapter..... unscrew them, trim off 1/4" or so, spread the strands evenly and screw the adapters back on.

Not a bad idea on the plug wires. Just be especially careful for the far right one (closest to the coils) - not much spare wire there! As Ray mentioned, screw the adaptors off the wire and screw them back on after trimming. The part that makes contact is like a skinny sheet metal screw - pulling them off will damage the wire more.

 

[jblanken64]

Throttle body synchronization and set idle speed ~1100. As far as the ECU codes are concerned. Reset them and see if they return. If they do, you should investigate further. How many miles on the bike?

TBS was done back in the April/May time frame and I've been trying to adjust the idle speed. There are some times where the idle will settle at 1100 just fine, but more often than not, it will drop below and stay there unless I feather the throttle. And average MPG per the trip computer has dropped from 42 to 35. Bike has about 48K miles.

It may be related to the work you just did....... You may have turned the key on while these sensors were disconnected. That will definitely set the cylinder identification sensor fault. Like Ross says, clear them and see if they return. As for the rough idle, there may be a bad connection of the spark plug wire to the plug adapter..... unscrew them, trim off 1/4" or so, spread the strands evenly and screw the adapters back on.

So how exactly do I remove the boots from the spark plug wires? I thought they were fixed. I haven't tried to reset the codes as the service manual seemed to indicate that they would clear by themselves. I don't recall seeing a clearing procedure. As far as disconnecting the sensors, I'm not sure where these are so I don't think I've disconnected them (yet, as I'm still checking the connections).

Joey.

 

[RaYzerman19]

The codes 11 & 12 could have appeared if the ECU thought something was wrong but wasn't, I've experienced this before. That's why you clear them and see if they come back. To erase, while in dIAG, scroll to 62 and switch the stop switch and they will clear.

To remove the spark plug boots, unscrew counterclockwise while pulling/working the wire out of the boot. Once apart, you will see the screw, trim, spread the wires and reinstall. Perhaps redo the TBS, suggest verifying that #3 screw is 3/4 to 1 turn out so you can better balance the others (sometimes Yama had #3 less than 3/4 turn out). May help, may not. Turn the idle adjuster out so the idle drops, then turn back in just enough to get 1100. Another possible issue with idle is that the throttle cable freeplay was adjusted too tight. Adjust the cable so mostly all freeplay is removed but has a smidge of freeplay. Try all these, go for a short ride and see where you're at......

 

[Viper Pilot]

also make sure you haven't lost any of the little rubber caps on the throttle body vacuum ports.

 

[jblanken64]

also make sure you haven't lost any of the little rubber caps on the throttle body vacuum ports.

Thanks. That was one of the first things I checked. It's certainly easy for those to come off.

 

[jblanken64]

I finally found the problem. I'm not sure how I missed it initially but there was a hole in a vacuum hose. I actually think the hole has gotten larger since the idle issue continued to worsen. After replacing the hose the bike runs as well as it ever did. The upside is that I know a lot more about some things, I have new plugs, a new air filter, and I got my PAIR blockoff plates installed. Te next step I was going to take was to clean my throttle bodies and I wasn't looking forward to that job.

 

[Niehart]

Good detective work. Sometimes that kind of thing is the hardest to find.

 

[RaYzerman19]

Interesting hole...... any clues as to what was vibrating against it to cause that?

 

[jblanken64]

No clue at all. It may have started out as a crack and just opened up. There didn't appear to be any rub wear on the hose or anything in proximity.

 

[RossKean]

Pinched with a pair of needle-nose pliers while removing the retainers for the TBS rubber caps?