XB12S Running Rich and Won't Idle

[turbostang52]

Gents,

Been dealing with this issue for awhile now and looking for some help.

The bike now starts, but only runs for 10 seconds or so and then dies. It runs really rich and rough. If I try to get it stay running, it pops in the intake (can see the combustion) and smells of unburnt gas.

What I've done so far:
Replaced the plugs with new NGKs (old NGKs were fouled and black but dry)
TPS reset
Replaced ignition wires
Checked breather re-route system and it's clear
Temp sensor and IAT sensor appear to be reading correctly

Asking for some advice on how to move forward.

 

[jriffe108]

o2 sensor?

 

[rchuff]

+2 on 02 sensor. what year bike would help?

 

[turbostang52]

Sorry for the lack of info… it's a 2007 Buell Lightning XB12S

Would an O2 sensor really be the cause here? I ask because on a car, the O2 sensor inputs don't make a difference in running condition (like rough/rich conditions) until the vehicle is in closed loop. I've confirmed through ECM SPY that the bike is still in open loop as I can't keep it running long enough to get it into closed loop.

Can anyone confirm if an O2 sensor effects running condition during cold start up while in open loop?

 

[Sirius815]

It won't. If it's running that rich at idle, have you tried to adjust the fuel map to make it run less rich?

On my '05 12R, I had the following "idle" values

TPS/RPM 0 800 1000 1350
12 100 110 110 125
8 100 100 94 79
6 80 75 68 54
4 75 67 52 47

 

[egobuster1]

my thing is here that if it ran fine before and you didn't adjust the fuel map then i don't see the fuel map being the issue.
i wonder if the fuel pump or the injectors are sticking open and just dumping fuel?

 

[Sirius815]

I'd agree, but why not take a look anyway just to be sure everything is still good with the maps? Might as well confirm that one as well.

 

[DualSportDad]

o2 sensor adjusts the afv. a faulty o2 will make the bike start to run worse and worse as the o2 gets worse.

on a car the o2 sensor will make it run bad as well. the o2 will adjust the fuel trims way out if the sensor is faulty.


https://www.youtube.com/watch?v=WBn0wa9gtp8

https://www.youtube.com/watch?v=zzPnFnUJVV0

 

[turbostang52]

first off, just want to say thank you for the plethora of replies… I really needed the help!

just to quickly touch on the O2 sensor question again… I am certainly not debating the importance of a working O2… I understand that it's necessary to understand what's happening in the combustion chamber regardless of a car or a motorcycle. That said, I just want to confirm if an O2 sensor on a bike controls running condition in open loop, as on a car the O2 sensor doe NOT monitor and control fuel during open loop. This is important because if the O2 sensor doesn't start changing fuel values in the ECU until the bike goes into closed loop, then the O2 sensor is not a concern for the cold start rough running condition. You were confirming this Sirius815?

Regarding the fuel values in the mapping, I agree with egobuster as they were never a problem before. On top of that, I have a known good ECU that made no difference in the running condition.

I fairly sure it's not a faulty pump assembly as I have swapped that out as well. I had a faulty pin in the connector on the pump side of the harness and so had an extra pump assembly. That change made no difference in running condition.

As far as the injectors, I do agree that this very well could be a strong possibility. I'm considering removing the throttle body assembly and taking the injectors down to RC Engineering (local fuel injector service shop here in Torrance) and having them cleaned. I know a lot of people on here don't seem to like injector cleaning but I've had nothing but great luck with RC. I have a turbo'd mustang that sat about 2 years when I moved back to CA and after diagnosing a no start condition, I found the injectors were clogged. RC cleaned them, flow tested and provided spray pattern information for before and after for each injector. On top of that, it's cheap at about $18 an injector (I get a nice discount cause I work as an engineer for Toyota). My only hesitance at getting them cleaned is that I don't seem to see a lot of failed injectors on here.

 

[turbostang52]

Another point on the injectors, I mention how there doesn't seem to be a lot of failed injectors on here, but then again this might not be the case. With all the fuel injector cleaning services I did on the older Toyotas (usually 2002 and older) to fix rough running conditions, fuel injectors could potentially be the cause for many of the Bueller's out there with that hesitation they can't seem to get rid of. With that said, I may try cleaning the injectors to see if this might help other Bueller's in the future...

 

[Sirius815]

Overall, the o2 sensor is not being "used" during open loop mode, however based on the signals sent by the o2 sensor during closed loop, the AFV gets adjusted. Your closed loop is very lean, or at least the o2 sensor is showing lean conditions to the ECM, then the AFV increases.

The AFV acts as a multiplier to the FULL fuel map which can result in very rich conditions if the o2 sensor is at fault and not actual running conditions.

(I think I should've been clearer in my post earlier and thanks to DualSportDad for his post!)

Onto the injectors - if they are "clogged" will that affect the amount of time they are "open" by sticking - or is that another issue. I'm no expert on injectors....

 

[turbostang52]

No worries Sirius, your explanation for how the ECU compensates fuel adjustments based on O2 readings makes perfect sense as the concept is the same on cars.

I ended pulling the fuel rails/injectors this morning as I knew it would only take about 10 minutes or so (no need to pull the throttle body as the RM says). I'm going to drop off the injectors tomorrow to have them flow tested and cleaned.

I'm probably going to go ahead and order a new O2 sensor as it wouldn't be a bad thing to have an extra lying around (I'm a Buell parts whore). I rather wait for the injectors to come back before I put in the O2 as I want to confirm what fixes and doesn't fix the condition. I'll update the forum when I get the results. Thanks for the responses guys...

 

[turbostang52]

UPDATE: FIXED!!!

So got the injectors back today and although they were slightly "out", they obviously weren't the issue with the numbers I received. RC Engineering confirmed the injectors were 300cc… the front injector was spraying 295 (designated rating as 'good'), and the rear was spraying 283 (designated rating as 'fair' ). After the cleaning, they measure a perfect 300. Although this won't fix the runs rough condition, it will only make the bike run better/smoother in the long run.

On to the next try… I decided to order a new TPS sensor this weekend after seeing a few You Tube videos online of a Buell that had a similar condition as my bike. Installed the sensor and did a quick TPS Reset, and PRESTO! She runs smoother than she ever has and I haven't even put a few miles on it yet (which usually results in an even better idle and drivability).

I'm pretty hammered with work the remainder of the week and so I'll test drive the bike this weekend and adjust idle (as I only did a quick TPS Reset) and report back.

Thanks to everyone on here that gave their input.

Time to get back on the road….

 

[anthonyoc]

This sounds very similar to what I'm experiencing. Can you confirm the following?

- Engine starts but stops after about 10 or 15 seconds
- Engine idles around 1000 rpm and even after it warms up, can stop as the bile approaches traffic lights
- Puffs and coughs at low revs in 1st gear as it pulls away from lights
- Smells strongly of exhaust fumes after a ride

I've just bought this bike so learning every day. It has about 21,000km on the clock, stock exhaust but has a K&N filter and the intake modification. Any help and suggestions are much appreciated.

BTW, any Buells in Melbourne, Australia?

 

[turbostang52]

Hey Anthony,

Need to confirm exactly what is wrong with the bike:

You’re saying that the bike can be taken out and ridden on the street, but it occasionally stalls while warming up and when coming to a stop at a light?

When you say it the bike smells of exhaust fumes, do you mean it smells of unburnt fuel?

I’d begin by pulling the spark plugs and checking the condition… I’m guessing they are black and you’re suffering a rich condition.

Have you done a TPS reset since getting the bike?

 

[anthonyoc]

Yes, it won't idle when cold. Just cuts out. When it warns up it will idle but when approaching a stop, the engine revs sometime drop below 500 and the engine cuts out. Did a TPS reset but not much improvement.

When it's running, there is a strong smell of unburnt fuel in the exhaust - running way too rich it seems. Below 2500 rpm, it will backfire or cough (not sure which yet) but it runs well above 3000 rpm. Spark plugs are likely fouled but probably as a result of running rich. It need to pull the over the weekend and have a look.

I'm going to drop it into a Harley dealer for a checkup and service. I'll learn more from them and possibly sort out the problem, too. Thanks for your help and any other observations are most appreciated.

 

[turbostang52]

I'd definitely recommend pulling a plug before bringing it into the dealer. You could have helped/corrected the issue when doing the TPS reset but the plugs were already fouled due to the rich condition. It's a long shot, but it's not a bad idea to see how bad they looked.
It's also not a bad idea to pull the air box and filter off and check out the interior of the throttle body. It's possible you have some buildup around the throttle plate causing it to stick… if so, get some carb cleaner and give it a good cleaning. Again, this is just another thing to check out.

 

[anthonyoc]

Thanks for the advice. Will do.

 

[jd.hd.buelly.crzy]

Sorry for trolling this site. But, I'm looking for answers to the your same issue? Did you ever get a resolution?

 

[TPEHAK]

Possibly the intake valves are covered by dirt and can not totally close the gap so fuel mixture blows back in the intake through the gap. I used seafoam to clean the engine, no idle and O2 sensor issues anymore.