Hi, I'm trying to help out my dad with his quad, and hoping for some advice diagnosing it. It's a 2015 A/C XR550 XT, fuel injected.
He was driving it down the lane and it just shut off, will crank but would not start. I confirmed the spark is excellent, so leaning towards a fuel related issue, I disconnected the supply to the injector. When the fuel pump primes, there is tons of fuel coming up to the injector. Next tried removing the injector, and with the fuel pressurized, cranked the engine to look at the spray. There is fuel coming out, but not a lot. Not like a car injector that I'm used to, but there was enough fuel coming through it to mist a paper towel. I also used a battery to manually open the injector, and it snaps open and closed as it should.

Next I poured a small amount of fuel directly into the cylinder. After doing this, the engine will start and run until the fuel burns off. So that rules out timing, electrical, etc.

I'm leaning towards the injector, but I am surprised that with the amount of fuel being sprayed that it wouldn't even kick. I am prepared to recommend replacing the injector, but I was hoping for a second opinion before I start replacing parts.
Would appreciate any other ideas people might have.

Thank you.
Edit: confirming there are also no engine codes.

 

Update: removed the injector entirely, cleaned it out with TB cleaner, and used low pressure air to force the solvent through. This gave a nice mist when opening the injector manually with a battery. Put it back in the machine, and still nothing.
So good spark, fuel is getting to and through the injector, runs with fuel in the cylinder, but won't kick when trying to start. Trying to get my dad to borrow a fuel pressure test kit so we can rule out a weak fuel pump, but I wouldn't think it would fail so suddenly.
Running out of things to try...

 

Fuel pressure could be low because of an clooged fuel filter so I would check fuel pressure just rule that out but does sound like low fuel pressure to me from all you have already done

 

https://www.partzilla.com/catalog/ar...-tank-assembly

 

Photo number 5 is pump assembly I have got an auto fuel filter to replaced the OEM they want you to buy fuel pump assembly

 

I have removed a pump assembly from tank an put lines back on an put assembly in bowl or tub of fuel just above fitler an turn power on watch for line leak from split or regulator not holding pressure an you can buy aftermaketpumps and other parts to do a repair job good luck

 

Thanks all for the replies. My dad just bought a fuel pressure test kit, so I will confirm fuel pressure tomorrow morning. Appreciate all the info, I will be sure to post back with the results.

 

So I completed a static pressure test, and the pump is putting out about 45PSI, which I believe is where is should be. Tons of fuel flowing up to the injector, injector cleaned and seems to be functioning as it should, good spark with new plug. Still no engine codes, but engine still won't fire. I am pretty good at engine diagnostics, but this has me stumped. Got a price check on a replacement injector, and it's over $300 Canadian, so I'm hesitant to tell my dad to go buy one without knowing for sure.
Again, if I pour some fuel into the cylinder, it fires right up and idles along until it runs out. I guess I'm still no further ahead.

Thanks for any ideas.

 

Have you check compression? if compression low engine has hard ignite fuel by itself.May need values adjusted

 

No codes IMO most of the time its mechanical