electrical headache

[estutjaweh]

Hi all,

I'm new here so first of all, pleased to meet you all!

I have an issue with my custom bike thats running an XB12 engine. Its electrical and doing my head in.

It ran ok last year but I had a huge air leak so this year I swapped the intake manifold over to a Sportster unit so it would exit sideways, but other than splicing the Harley TPS onto the Buell loom in place of the old Buell part, I kept all the electrics the same. Now that all worked fine and the bike started. Only two thinsgs worth mentioning here are that the fuel pump refused to stop the usual priming noise after reaching pressure, but it did start )it didn't hold idle as it still needed a tune, but it did start).

I completed a TPS reset (ECMSpy) and stared to set up the idle. After TPS reset, the ECMSpy refused to show TPS position at all. I decided to give my self a break at the end of the day and instead, removed the fuel pump to check the regulator etc. were all okay to find out why the prime noise wouldn't stop. All appeared werll so I remounted the fuel pump/filter assembly.

Now thats all small stuff and I can find a solution. What is freaking me out is the next part.

After I refitted the fuel pump etc and turned the key to the power on ... no fuel pump noise at all. Not even the green Neutral gear light appeared now. Then, as I folded the stand away, the fuel pump suddenly primed again (still non-stop as before) and the green neutral light came on and the bike started as is did earlier. This time however, the green light wouldn't turn off as I shifted into other gears. AAAAGGGHHHHH!!!

I have checked all fuses, the relay through which the stand goes looked a little tired so I even sourced and tried a new one. I also have a RACE ECM flying about so I swapped that out to see if it made a difference. Nope...nothing helped. Any ideas? How is the stand and fuel pump and neutral gera light connected? Any help will be greatly appreciated.

 

[Chicknstripn]

Does your bike have a neutral safety switch? Early models do but you didn't mention what year you're dealing with.
Did you check the fuel pump wiring, inside the tank? Usually the pump primes continuously when a wire on the actual pump becomes frayed and starts rubbing on the pump body. It doesn't take much of a fray to cause issues. You could also have a pump on the way out. Start researching fuel pump rebuild threads to give you a better idea of what your dealing with.
Could you elaborate a little more on what you have going on with the HD TPS wired into your buell harness? You might want to check that wiring if you're losing TPS signal.
And here's something that is extremely simple, so simple in fact it's usually over looked; make sure your battery is in tip top shape. Also make sure ALL your ground connections are good and clean. There have been many SOS "electrical issues" on this forum that have been traced back to faulty wiring or bad ground connections.
www.buellmods.com
check out the above site for a service manual.
Good luck

 

[Fatty SS]

Mine suffered the frayed pump wiring. For mine, it kept blowing the ignition fuse but I read of lots of wonky problems from this issue. Definitely worth a second look to rule these wires out.

 

[estutjaweh]

Hi,

Thanks for your help so far.

The bike does have a neutral switch which worked perfectly up till this point.

The TPS works fine and the wiring hasn't been altered after removing the fule pump assembly for inspection so I don't believe this can be the cause of te issue.

The Battery was on a trickle charge all the time and is in tip-top condition so I am sure this is a lso not a factor.

I've had enough so have sort of given up at the moment and handed the bike to my local workshop to see if they can get authorzation for me to convert this back to carbs. The laws here in Germany are rather strict regarding this due to emissions checks etc. so wish me luck! I can always convert back to EFI again later when I have money/time/patience.

Thanks again for your help. Here is the beast below which is creating all my headaches.

 

[Cooter]

Slick bike for sure:up:

Seems like going to carbs is a little drastic for such a small issue.

How about we start a proper diagnosis, starting from one point and continuing logically until we find the problem? If you're interested in doing that, I'll help

 

[ztied]

Cooter and the guys have a lot of knowledge on this site, and can help you get it going