Starting issues

Barry said:

Good day all. I dropped a valve 3 years ago and decided recently to bring the bike back to life. Motor is back in, but doesnt start. Engine is turning over, pump is running high pressure and there is spark (starts when adding fuel to throttle bodies). It does not give me an error code or Fi light. I have unplugged a couple of sensors and some of them does not give an Fi light when ignition turned to on (maybe it is normal?) The ones mentioned include:
- cam positioning sensor (also swapped it as I have another one)
- fuel injector (one unplugged)
- stick coil (one unplugged)
- sub throttle valve

Unplugging the main throttle bodies plug does give Fi light.

I have read similar threads from the past, but nothing really matches my description.
Would really appreciate all comments.

Thanks!!
Barry

Click to expand...

Welcome!

First of, what did you do to "prep" the bike before letting it sit for 3 years?

First thing I'd be doing is flow testing all the injectors. That's an awfully long time to let fuel be sitting in the system. Lots of crap, water, debris, broken down fuel, etc sitting in those lines if you didn't drain and purge the system before letting it sit around.

Also, the above confuses me. There shouldn't be any spark to the plugs until the motor is actually turning. It has nothing to do with the fuel pump. So unless you've checked the spark plugs while the motor is turning over, then I'm not sure how else you could verify that.

Some sensors will cause an FI light, others won't. Unplugging an injector won't cause it. Neither will unplugging a coil. Crank sensor, cam position sensor, main throttle sensor, vehicle down sensor, etc. will though.

This sounds like a fueling issue more than anything. It's not getting fuel into the cylinders is my guess. Fuel pressure, good flow to the cylinders, even a compression/leak down check on the cylinders to be sure you don't have a leaking valve or a stuck ring or anything dropping the compression to the point it won't run would be the first things to check imo.

firing off when fuel added to int. tact eliminates ign. issues. jump ur kickstand switch by connecting the two wires together, problem persists, connect test light to neg side of battery and probe the 4 injector wires at injectors that are common colored, white/red stripe i believe, they should all be hot switch on. if so now test different colored wire on each injector. it brings timed ground signal to injector from ecu to fire injector. connect test light to positive side of battery and probe odd colored wire. it will pulse test light engine cranking over when ecu sends ground signal to injector to fire it for starting/running. this will eliminate or affirm any ground/wiring/connection/ecu problem and narrow problem to pump, kinked line, or inj. however, never seen a set of 4 injectors so clogged bike will not fire and i recentley had a set of 310 cc injectors that flowed in the 70's total before cleaned. that bike cranked easily, just broke up above 6k. cant determine fuel pressure without a gauge though, and fuel pumps will fool u. test inj for constant positive, and pulsed neg signal. will really narrow problem down.

if i understand what ur saying correctley, u have positive constant power to each injector and pulsed negative signal present to fire injectors on all 4. ur hearing audible click from 2 and no click from two? if correct u have a simple clogged/stuck injector problem and i suspect compounded by fuel pump. sittting 3 years with fuel in system can corrode both. throttle bodies just a housing to direct/meter air flow, basic housing does not go bad, but may be cheaper to replace if good fuel injector cleaning service not avaliable instead of replacing injectors alone. diy cleaning of injectors will not work well if at all. replaced several fuel pumps, had many injectors professionally cleaned in last couple of years from sitting in fuel. have 5 sets to get cleaned right now, 3 pumps to replace. find professional service to restore injectors or replace used which has become a roll of the dice. injectors cleaned with correct power/signal to fire u should run great if fuel pump not affected, suspect it is. if avaliable swap a tank and tb;s from another bike for results. ur getting there.