diag code 31 question

I was driving down the freeway, and suddenly get the 'check engine' light. I pull over and see plenty of oil and coolant, so I rode home. I pulled the diagnostics and found #31 (lean condition) showing and it won't erase. The FSM says #31 indicates lean running due to coil 2/3 going bad, or the O2 sensor gone bad, or another lean condition tbd. ???

So a new O2 sensor looks like $250 @ RA. , or can I use a 'non yamaha' O2 for $62??? Or can I remove it and add some wire to 'short it' out?

FSM says it's still rideable, but I am cautious. I HATE the yellow light on. What's the next step to running right?

When you install a PC3 or PC5, you disconnect the O2 sensor.

It shouldn't be the problem.

Fault code 31 also suggest a few other items, such as low fuel pressure, clogged injectors or a crook ECU connector.

There has been cases of high resistance on the ECU connector before.

Pretty sure that means the engine is about to grenade. Give ya $100 for it.

So, I have 73k on my '03. She runs like a top (raped ape) ... Might the (added) heat blanket be making it too hot on the ECU?

Or, I had a (30mph) low side in June, rode 1500 miles since. Could the low side on the right side make the O2 sensor go bad (1500 miles later)?

Unplug the O2 sensor, go to diAG code 62 and toggle the red RUN/STOP switch to clear history. Go for a ride and see if the code comes back. As mentioned, when you install a PC III the O2 sensor gets unplugged and it doesn't set a code. The only way the ECU would know if the engine was running lean would be the O2 sensor and associated wiring. Next action depends on what you find.

For some reason, the '03 and early '04 would sometimes set a Check Engine code due to the O2 sensor after it was washed or driven through heavy rain or deep water. You haven't been washing your FJR recently have you?

You can ride your FJR with a bad or open O2 sensor and have no problem with reliability.

Did you notice any miss? That would confirm/rule out coil issues. Unplugging the O2 sensor will only disguise any pending failure untill it just stops running if it is anything besides the sensor itself.

supertankerm60a3 said:

...Unplugging the O2 sensor will only disguise any pending failure untill it just stops running...

Click to expand...

I'm only suggesting the O2 sensor as a diagnostic step, leading to additional troubleshooting to get to the root cause, not as a 'fix'.

Guys, Thanks for your patience. (death in the family, plus work and stuff)

I unplugged the O2 connection, toggled thru the diag screen, and @ 62, I toggle the red button to erase.... and IT WONT GO AWAY! (Stays @ 1 error)

I try to toggle the red button @ 31 and the check engine light flashes 4 times and goes out. The 31 remains on the start screen and the light stays on (but runs great!)

So, It's not the coil (runs great), I assume the injectors are good (runs great), It's not the O2 sensor (unplugged and runs great), what next? TIA, Roger

Using diAG, check the atmospheric sensor, the intake pressure sensor and the temperature sensor. Those sensors along with the O2 sensor are involved with determining fuel compensation. Being careful, unplug the hose to the intake pressure sensor and be sure the hose isn't plugged with goo. Don't poke or spray anything into the sensor opening or you will kill it!

When you try to reset the code and it won't, leads me to think the ECU sees one of these devices as out of range and won't let the code be reset. If the engine isn't running the ECU wouldn't normally know that fuel compensation is wrong unless a sensor is completely out of range when the engine isn't running. If you can, try to trace the O2 sensor wires, the wire harness bundle it goes into and at the ECU. If the O2 sensor wires are pinched or broken the ECU would set an error code that you couldn't reset.

If one of the sensors in this list is bad the FJR ECU would use a default look-up table and run just fine, the only way you would know something isn't right would be a check engine light or a set code. I have run my FJR with the intake sensor disconnected and the ambient pressure sensor unplugged (as a troubleshooting aid) and it ran perfectly normal.

Ion, Thanks for all your insight!

The codes are 1-17, 2-730, 3-22 cranking, 5-31, 6-37, 7-0, 8-.7, 9-11.9, then 20,21-on, then 30-0,31-0, etc. So they seem ok.

I pulled the hose (carefully) and it is clean and dry. Then I got 31 and 13 until I unplugged and replugged in the intake sensor.

Now just 31, but she still runs great! (Maybe get some elec tape and cover it up?!?!?! )

Update... The good news is I found a pinched wire coming from the O2 sensor! It was (slightly) pinched behind the primary cover (took it off last winter to do a valve check). Funny, I rode for 5000 miles before the code showed up. It still won't erase, but the FSM says ride it until the light goes out?

The bad news is now it won't start! It cranks 'till the cows come home (not starter) but no fire! It sounds different as well, spinning but not even trying to catch, like the FI or spark is cut off. (1 BIG back-fire) I can pull a plug just to check, but what have I done to upset the 'runs great' bike I had yesterday? Does it stem from the O2 search, or is this a new issue? I searched 'spins but won't start' and found lots of ignition switch issues, but this is new.... to me.

Good find for the O2 sensor wire!

Check diAG for stored codes, I believe you have done this and only see the O2 sensor. If this is the case, and your check engine light isn't flashing you probably don't have a serious issue.

Use diAG actuator code 30 & 31 to fire the plugs, you should faintly be able to hear the plugs sparking. Use actuator codes 36 - 39 to fire the injectors, you should hear them clicking. Use diAG actuator code 50 to check the fuel pump relay. When you are at code 30, flip the red RUN/STOP switch off and back on, this will fire plugs 1 & 3, the same process for the other actuator codes. You may want to read about the actuator codes.

If this all checks out OK you most likely just have a flooded engine. If you can, trickle charge the battery overnight. The next morning hold the throttle wide open and crank the engine 5 - 10 seconds, wait a minute or so (to keep from overheating the starter motor) then try cranking again, repeat until it starts to fire and then actually starts.

The codes are 1-17, 2-730, 3-22 cranking, 5-31, 6-37, 7-0, 8-.7, 9-11.9, then 20,21-on, then 30-0,31-0

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Code 1 should be 17 with the throttle in the idle position and ~100 with the throttle wide open

Code 2 is a little low, it should be up around 1000 but this is isn't critical

Code 3 is acceptable

Code 5 says it was around 90º when you ran the tests

Code 6 says the coolant was in the mid 90º area

Code 7 speed sensor says that your FJR was not moving

Code 8 says your FJR hasn't flipped over

Code 9 says your fuel injectors are seeing 11.9 volts (this is good)

All seems OK.

I gotta believe this has crossed your mind but it sure sounds like the ol' Fast Starter Syndrome. Try WOT for three to five second bursts several times to see if anything happens.

Edit: Err, yeah, go with Ionbeam's advice first.

BigOgre said:

I gotta believe this has crossed your mind but it sure sounds like the ol' Fast Starter Syndrome. Try WOT for three to five second bursts several times to see if anything happens.

Click to expand...

I admire the way you say that so concisely without all the superfluous words I tend to use

No F---ing joy! This is embarrassing that my fine FI bike can't start 'cause it's FLOODED?!?!?!

I tried WFO after charging all night (and buttoned her up) thinking this would work, got 1 puff, and tons of 'not a chance'.

Now I am recharging the battery, went for a ride on my '81 KZ w/ a half dead battery, and carbs, and she started right up! (What BS)

So I will pull the plugs, add a little oil, and try it tomorrow. (you might tell i'm a little frustrated by this sh--)

Well that sucks.. I know the last time it happened to me it took about a half dozen starter bursts and a little less than full throttle. Sorta felt it out.

BigOgre said:

Well that sucks.. I know the last time it happened to me it took about a half dozen starter bursts and a little less than full throttle. Sorta felt it out.

Click to expand...

I can't recall what I did to cause problem (troubleshooting some other FI issue) but took about a dozen times of WOT before engine fired up.

Joy! I dried the plugs w/ brake cleaner, and dropped (a lot) of oil into each cylinder. Same drill yesterday, and it tried at first, then nothing for 3 minutes.

Today I did it the same drill, but tried no throttle, then a 1/8 throttle and ZZZOOOOOOMMMMMM! Full power in 3 seconds.

I think drying the flood overnight, and slight throttle may be the trick. (4 minutes of WFO is nuts)

AND the idiot light from my error 31 went out as rode around town.....bonus!

Thanks to all for your help and patience! Sincerely, Roger