2004 12S starting issue

[Scallywag303]

Having a problem with my 04 12S, it has 2300 miles. D&D, K&N, EBR ecm programmed for this setup.

Bike starts up fine when cold and runs fine until it is shut off, then it will not start again. It starts then stumbles and dies immediately.

In the last month, I have replaced the battery due to a bad cell, battery is now fully charged and charging system is functional per service manual. My cam sensor had a crack in it and would cut out in the rain and when hot, so that was replaced also and timing mark is exactly the same as it was prior. After I replaced the cam sensor, I went on a 250 mile ride and it worked great all day, tried to start the next day and nothing, it would start with carb cleaner and I had spark so I replaced the fuel pump, now it starts and runs fine on cold start, just wont start hot. I'm probably going to need fuel pressure gauge, that's my only real uncertain. I do have spark for sure. Also I tried putting my old ECM back in and TPS resets with both and that didn't change anything.

Is there another sensor that will cause this that I have over looked? Or did I just get a junk fuel pump?

Here is a video of it.

 

[user_deleted]

excellent details and historical account of bike problems on your part. what i would do with the hot-no-start situation is immediately remove the airbox cover and airbox lid....then dribble a touch of fuel or starter fluid down the TB, then see if it fires momentarily. if so you clearly have a no-fuel issue. if that be the case use the info below to trouble-shoot possible pump problem. also switch the auxilary relay with the key switch relay and see if it starts. if so key switch relay at fault. fairly rare but a faulty O2 sensor will NOT always dump stored trouble code into ecm. if you have found that the bike was getting "lazy" on warm throttle....had to roll out of throttle.....bike then came back to life.....tell-tale sign of faulty O2 sensor but never saw one so bad that the bike would fail to warm start. take a look at the below.

here: If the low fuel wire wears through the low fuel light will come on, if the fuel pump power wire wears through the fuel pump fuse will blow and if the fuel pump control wire wears through the pump will constantly prime with the ignition on / engine off.
You can measure the sensor line to ground on the pump connector (it is the pin corresponding to the yellow/red wire in the loom). The fuel pump body is grounded. If the wire is worn through this reading would be close to zero ohms.

 

[Scallywag303]

I did try spraying some carb clean in there to see if I could sustain an idle. It didn't have an effect on it like it did before I replaced the pump. It did start after cooling down again, I rode it around about 30 minutes and now its not starting again. This time it did seem like it was cutting ever so slightly under load once hot, but I could only hear it and couldn't feel it. I did notice about the same time the tach was really stuttery, almost like it was stuck. I tried to get a video but it returned to normal before I could.

I'm now wondering if my coil has an intermittent problem, I'll test it again tomorrow, I also have a spare coil I'll try in it. The bike does have new plugs and no codes, I also checked all the grounds under the airbox and on the rear tail and they tested fine with a meter.

I think she is just being a drama queen and jealous because I got another Buell...

 

[Chicknstripn]

Other Buellers have had similar HOT running problems and discovered it to be a faulty CPS.
Not saying run out and buy one but start researching "bad CPS symptoms" and see what you think.

Good luck

 

[Scallywag303]

Chickn, I did test that and it has been replaced already, not just throwing parts but it had a physical crack in it.

 

[Chicknstripn]

Is your check engine light coming on at all?
Have you used ECMspy or ECMdroid to check for codes?
Other than what lunatic has already suggested I'm at a loss...

 

[Scallywag303]

No codes, using ECMdroid. I did pull the coil off and tested it and and put on my spare that was off a running bike, and no dice.

I did another tps reset and it fired up, rode it, let it sit for 15min, no start, tps reset, nothing. The bike has cooled off and is running now, but if you blip the throttle it cuts for a second, if you roll the throttle it's fine. watching the voltage with my DVOM it spikes on the blip from 1.1v to 2.6, if roll the throttle to the same point I was blipping it to, its at 1.7-1.9v. I'll get it hot again and test the TPS voltage and resistance and see what happens. I'm probably going to buy a fuell pressure gauge this week just to verify its functional.

 

[Chicknstripn]

Does your fan function seem normal?

And have you looked into possibly having a faulty AIT sensor? I think lunatic mentioned that too. It's the sensor in the airbox. I couldn't tell you how to test it. You'd have to check the manual for that one.

I haven't used ECMdriod before. So I couldn't tell ya much about your readings on the TPS. I just know when my TPS went out, years ago, there were no codes and no signal from it on spy. My bike wouldn't start at all when the TPS was bad.
Do your TPS readings change from when you reset it to when the bike starts having hot starting problems?

And I think lunatic mentioned your O2 sensor could be the culprit. You looked into that?

I know I'm throwing a bunch of stuff at you. I'm just thinking out loud hoping it some how helps.
I'll shut my yapper if I'm just confusing things even more for you.

 

[Scallywag303]

Not confused at all, I feel like I've tried everything but am missing something so any and all suggestions and help are very welcome.

Fan functions normal, comes on when key off and runs for a while, will come on while riding at times.

I did test the IAT and is was showing proper voltage per the manual at ambient temp with the airbox off. I've read TPS voltage from both ECMdroid and manually with my meter. I did have another no start and TPS read the same as when it started.

I have not touched or read the O2 sensor, my understanding, which could be wrong, is that the O2 only functions while running?

The bike had a Jardine on it when I got it and the K&N with no programming at all and was really lean and running pretty hot. Not sure if that is what created any of these problems though.

 

[Scallywag303]

Alright, I replaced the cam sensor a second time, put about 200 miles on it and it seems to be fine now. This first one(original) had a crack on the back pickup, second one shown looks to have melted a touch, new onews is hopefully not going to fail on me. I checked wiring nothing looks off so hopefully it was just bad luck on the first replacement.