So what's the problem!?!

[lowkey]

I could write a novel, but I'll try and keep it short and sweet. I went for a ride last week about 50 miles to start dataloging to tune my maps, also worked on dialing in a square idle for two days before that. It was either later the same day or the next day that when I started the bike, it wouldn't idle for more than 20-30 seconds and backfiring through the intake. I flashed the saved EEPROM I had on the bike since I bought it but no change. Keep in mind the ride I did with the modded map was fine, just back to the stock one to rule it out.

Here is the video description to quickly cover what I've already done/looked over.

No codes(ECMSpy), TPS reset, purged fuel, changed plugs, tested coil/wires(OK), checked all harness wiring/ecu for cracks, wiggle tested(OK),static timing checked(OK), inspected cps(visibly looks OK)

In the video I hold the throttle steady trying to keep 3,000RPM's the fluctuations are the bike not throttle input to be clear. This is also the longest it has kept running at idle all week, and engine was cold for video. Note you can see EGO's going wild to keep it idling.

So I'm open to ideas here, I feel like it is going to end up being the cam position sensor but I really can't drop $130.00 without knowing for sure. From the threads I could find SOME people describe similar symptoms and no codes, except it gets worse as it gets hot(on theirs). Other posts say it threw all kinds of codes or won't run at all.

To test it proper I'd need an oscilloscope, which I don't have.http://www.badweatherbikers.com/cgibin/discus/show.cgi?tpc=3842&post=2241189#POST2241189

Or there was this tread stating he saw abnormal voltage for CPS in TunerPro but never followed up if the bike was fixed. He also posted screen shots of doing it with TunerPro but I'm not a member so can't see em...
http://www.buelletinboard.com/forums/showthread.php?16422-Severe-hickup-with-CEL/page1

Is that lag on the diagnostic page with the CPS box (0 green 5 red)? Its either signal lag/drop out from the CPS or bluetooth to ECMSpy refresh lag but I'm not sure which...

 

[Cooter]

It's gonna be hard to start diagnosis in the middle of where you are now and not know the basics.


Backfiring through the intake can be a sign of bad or erratic timing, a bad CPS can do that, and so can a lot of other things.

Being lean can do that too. Checking Fuel pressure should be easier.

 

[AZmidget91]

Always check the mechanical stuff first. Fuel pressure and intake seals.

 

[lowkey]

It's gonna be hard to start diagnosis in the middle of where you are now and not know the basics.


Backfiring through the intake can be a sign of bad or erratic timing, a bad CPS can do that, and so can a lot of other things.

Being lean can do that too. Checking Fuel pressure should be easier.

Basics of what?

Always check the mechanical stuff first. Fuel pressure and intake seals.

Forgot to mention I checked seals and that they've been replaced not to long ago with James blue seals

As for fuel pressure, if pump primes and shuts off as normal is it not triggered by proper pressure? Seems it would keep pumping to build pressure. The last ride mentioned had no issue with power/lean condition... then all of a sudden...

 

[AZmidget91]

The pump needs to provide constant pressure while flowing. If it isn't flowing it is easy to build the pressure even with a problem.

 

[lowkey]

The pump needs to provide constant pressure while flowing. If it isn't flowing it is easy to build the pressure even with a problem.

Should I see constant 51PSI even when running? No pressure drop for open injectors? I can borrow one and try tomorrow.

Cole, what about the CPS box lag in the video on ECMSpy? Normal to read like that?

 

[Simplymichaeljr]

In the video it looks like the drop in rpm is happening at the same time as the lag in timing. Did you check the timing by putting the bike on a stand and putting it in fifth gear and checking it using ecmspy?

 

[Chicknstripn]

I believe he stated that he did perform a static timing test.
Normally in a situation like this I would say to check the intake seals. Even if they have been replaced recently the repair could have been done halfhazardly. I'd perform a test to make sure the intake seals are sound. Google "Buellxb intake seal test" and you should get some good direction on that.
The other thing I would check is the fuel pump. However, you have mentioned that it primes normally.
How old is your O2 sensor? Your issue could be the O2 not reading correctly.
What does your AFV read before and after a ride?

There's a way to test the CPS using a heat gun or hair dryer. I wish I could lead you to the post where someone used this procedure but it been a while.
I think the gist if the test is you heat the CPS with the hair dryer and the bike starts to act more and more erratic as the heat builds up. I've never tried this test but see if you can find info on it.
The above test might not help you if your O2 is bad and hasn't been ruled out. Faulty O2s exhibit symptoms as heat builds up.

Not sure if I've helped or just confused you more.

Good luck

 

[user_deleted]

There's a way to test the CPS using a heat gun or hair dryer. I wish I could lead you to the post where someone used this procedure but it been a while.
I think the gist if the test is you heat the CPS with the hair dryer and the bike starts to act more and more erratic as the heat builds up.

that's precisely correct carlos. a heat-gun works well...a hair dryer won't do the job. run the bike till you can feel warmth however slight in the cam cover particularly around the bullet area. then with bike idling heat the bullet area which holds the cps assembly. use common sense but if the cps is faulty and in particular those with "goop" leaking out of the assembly....the addition of heat will cause erratic behavior and even shut-down.

 

[ocgreenmachine]

I will say that I had this problem with my 09' XB12 back when i first got it... It turned out to be a TPS sensor on its way out... never threw a code. It would backfire out the intake and sputter and die unless I rolled on the throttle.

 

[Chicknstripn]

Was your faulty TPS still showing a signal on ECMspy? I had a TPS go out and the bike wouldn't crank at all. No codes either. Only way I knew it was the TPS was the fact that it wasn't putting out a signal.
So, that leads to my next question: is the TPS showing a signal? And if it is, does it stay set at what you adjust it to?

 

[Simplymichaeljr]

^^^^^in the video it looks like it jumps between 5.9 and 6.4 IIRC (without watching the video again because I'm lazy, but I do recall taking a mental note of it)

 

[lowkey]

In the video it looks like the drop in rpm is happening at the same time as the lag in timing. Did you check the timing by putting the bike on a stand and putting it in fifth gear and checking it using ecmspy?

Timing is dialed, I've done it 3 times now in the last week.

I would say to check the intake seals. How old is your O2 sensor? Your issue could be the O2 not reading correctly.
What does your AFV read before and after a ride?
Good luck

Intake seals are good and tested, with the tack jumping around regardless the test is not so easy but it consistently does what it does, no noticeable drop or rise from spraying the hell out of them. 02 was changed not to long ago (roughly 3K miles). The bike is unrideable in this state but AFV was consistent 103-105 for the rides leading up to this issue, I was monitoring like crazy as I was working on the maps at this time. I'm very familiar with leaking intake seals and faulty 02 sensors symptoms. For ruling out intake seals they were tested and RPM's are not slow to return as would normally be a tell. For 02 sensor being ruled out, engine is dead cold (ECU not looking for values at this temp). 02's symptoms get worse as temps go up unless they are fully dead, then issues no matter what.

I will turn off 02 referencing in ECMSpy to rule it out completely.

Use common sense but if the cps is faulty and in particular those with "goop" leaking out of the assembly....the addition of heat will cause erratic behavior and even shut-down.

No visible damage or "goop", actually looks brand new. I pulled it out to inspect the backside as well as the pickup and all appears brand new condition. I will grab a heat gun to try, what is weird is this is a dead cold engine in the video and running condition appears to stay consistent from cold to end of video (about 5min).

I will say that I had this problem with my 09' XB12 back when i first got it... It turned out to be a TPS sensor on its way out... never threw a code. It would backfire out the intake and sputter and die unless I rolled on the throttle.

TPS is working perfectly(verified consistently reading 5.1 closed and hitting marks along the way until WOT) and of course set properly

^^^^^in the video it looks like it jumps between 5.9 and 6.4 IIRC

You are correct, the TPS value was bumped slightly from a solid 5.1 for the video as I didn't expect it to idle more than 20 seconds. I wanted to "try" and give it a fighting chance by setting idle roughly 1200. the jump in numbers from 5.9-6.4 will happen when idle adjuster is between values. One click left or right will settle the number to a rock solid state. I've helped more than a few members on here diagnose TPS issues.

 

[Chicknstripn]

Maybe you should pull the pump and replace the filter and screen.
Could be a gummed/gunked up pumo is causing the fuel not to flow properly. Not sure if fuel PSI would change due to this. Just trying to throw out ideas.
You've ruled out almost everything else.

Oh, and just for the hell of it, pull one of your plugs to make sure they're not fouled.

Good luck

 

[lowkey]

Maybe you should pull the pump and replace the filter and screen.
Could be a gummed/gunked up pumo is causing the fuel not to flow properly. Not sure if fuel PSI would change due to this. Just trying to throw out ideas.
You've ruled out almost everything else.

Oh, and just for the hell of it, pull one of your plugs to make sure they're not fouled.

Good luck

Yes I'm with you, as of now I'm focused on pump/regulator/fueling or CPS. And yes plugs were fouled on account it wouldn't run more than 20-30 seconds, used OEM in normal burn condition went in temporarily. Also fouled plugs mean no lean at idle condition.

 

[lowkey]

Well I didn't get any further today... borrowed a half assed fuel pressure kit and spent more time than I should have trying to adapt it to work with the buell quick connector and fuel rail. I ended up breaking off one of the locking tabs on the quick connect so I cut the fuel line just past the the barbs on the quick connect. I should be able to clamp that to a brass barb and get the gauge hooked up from there. I forgot to bring the heat gun back with me so I'll have to remember to grab that next time but I'm just going to focus on fuel pressure first then move to draining the tank and flushing as well as pulling the injectors and flushing them if the pressure ends up being good. As for the quick disconnect, I see you can grab them in a two pack for about $10 bucks at the local parts store or amazon. I only had to cut the line a half inch shorter so it may not have to be replaced but it doesn't really have any length to spare to begin with...

Complete OEM fuel line (both end connections attached) isn't bad at $28.00 but shipping is $14.00 more and the down time kills it unless I have to.

Also recovering from a severely herniated disk has got me moving all kinds of slow and not motivating me!

 

[ocgreenmachine]

I had my bike at Harley for a month having them try diagnosing my problem. TPS never threw a code. They replaced the IAC and messed with my maps and couldn't figure it out even though I told them there was someone on youtube who had the same symptoms who had a TPS that was going bad and never threw a code. After a month, I got the bike back and it still did not work. I went to autozone, bought a new TPS, replaced it in 30 minutes and the problem was fixed.

TPS is working perfectly(verified consistently reading 5.1 closed and hitting marks along the way until WOT) and of course set properly

 

[lowkey]

I had my bike at Harley for a month having them try diagnosing my problem. TPS never threw a code. They replaced the IAC and messed with my maps and couldn't figure it out even though I told them there was someone on youtube who had the same symptoms who had a TPS that was going bad and never threw a code. After a month, I got the bike back and it still did not work. I went to autozone, bought a new TPS, replaced it in 30 minutes and the problem was fixed.

TPS is easy enough to diagnose through ECMSpy, to rule out erratic voltage/input mark your grip with a piece of tape and line at closed position then tape on the grip control. Mark the closed position, 25%, 50%, 75%, and WOT and record the readings at each tape mark over and over, will read the same if working properly, lastly sweep from closed to WOT and observe ECMSpy screen for smooth and accurate sweep. Most likely your TPS was zeroed wrong so map cells were off, or the actual TPS unit lost some tension in the spring loaded pickup that reads throttle plate. This can be fixed loosening the two 7mm bolts and turning the TPS clockwise to remove the free play in the spring and redoing TPS reset.

 

[lowkey]

Alright, got the fuel line connector from amazon on Saturday and got around to repairing it today.


Here is the P/N and new connector on the yellow tag right with broken stock one on the left


Here is the stock one, 4 prong and slightly shorter over fuel rail connection


New Dorman connector 2 prong


I used this to hold the hose with about 3/4inch of the hose sticking out. I used a heat gun for 20 seconds and with gloves on and some silicone spray on the new connection, was able to get it together no problem. I was watching a few videos on youtube and they made it sound like it was going to be a major pain without special tools, especially because this connector is a 90 degree bend. I didn't remove the fuel line from the bike completely because it feeds in through with the wiring harness and looked like a nightmare. I had the fuel completely drained and also removed the other end of the line at the pump and let it sit disconnected for a while to get rid of fuel vapor while using the heat gun.





Here it is repaired and installed.

Keep in mind this is the cheapest way to repair your fuel line at a cost of $10 for 2 quick disconnects as long as you have a heat gun and something to clamp the line while you install the new connector.

I also tired to source the inner retaining clip for the stock 4 prong so you could just replace that but no luck... I also tired to see if the 2 prong new white one would fit the 4 prong housing but it won't. The good thing is you can source the white clips for the Dorman one at your local parts store if you run into an issue, or buy a 6 pack for about $6 bucks.

I also rented a line disconnect kit and fuel pressure kit from Autozone, Nether will work on the bike... I've yet to see a kit that will work with these quick disconnect lines and you would also need another line from the gauge to the fuel rail. As for the disconnect tools there isn't enough length on the rail to get the tool in there and get it off, I'm sure you could chop the plastic tool shorter to work but couldn't do it to the rental set. The tool "may" work with the stock connector without modding it but not this replacement connector as you can see in the pictures. Got everything back together and its just like new but now I can get back to why the bike doesn't run... put in seafoam and 91 but it's worse than it was in the video.

I guess I'll have to start looking for CPS... if someone has a spare one they are willing to sell or let me borrow I could cover shipping both ways!?!

 

[Cooter]

So, whats the fuel pressure? Or were you hoping sea foam would 'fix' it. Hahaha.. Sorry...:black_eyed:


Tiny space at connections can be a bear to work with. More than once I have resorted to a simple 90* pick for the lock ring with pretty good success. Or a 1/2" long piece of the same plastic fuel line, split down the side and slipped over the existing line... then pushed into the connector. Remember, all you are doing is getting the tabs over the moulded barb on the line.