2018 Defender cranks but won’t start

[R Chris]

2018 Can am Defender Lone Star Edition. Had a check engine light on. It would start for a second and die. I used a shot of starting it would then stay running. I got a code P0131. I put a new O2 sensor. It still did the same. It ran like it was starving for fuel. Got another code P1171. I changed the fuel screen. Now it won’t start at all. It runs on starting fluid but not on gas. I put a new fuel pump in it. Still won’t start. Not sure what to do now. 

[Rudy]

On 10/1/2020 at 8:36 PM, R Chris said:

2018 Can am Defender Lone Star Edition. Had a check engine light on. It would start for a second and die. I used a shot of starting it would then stay running. I got a code P0131. I put a new O2 sensor. It still did the same. It ran like it was starving for fuel. Got another code P1171. I changed the fuel screen. Now it won’t start at all. It runs on starting fluid but not on gas. I put a new fuel pump in it. Still won’t start. Not sure what to do now. 

Can you hear the fuel pump come on when turning key to ON position? Fuel pump fuse?

[R Chris]

I figured it out.  Turns out when I first pulled the fuel pump the O ring on the fuel pump fell out so I installed the new one and it started right up with no check engine light on. Thanks for your reply. 

[A hunt 2 remember]

13 hours ago, R Chris said:

I figured it out.  Turns out when I first pulled the fuel pump the O ring on the fuel pump fell out so I installed the new one and it started right up with no check engine light on. Thanks for your reply. 

AWESOME!!!

[Myrt Mitchell]

On 10/7/2020 at 7:49 PM, R Chris said:

I figured it out.  Turns out when I first pulled the fuel pump the O ring on the fuel pump fell out so I installed the new one and it started right up with no check engine light on. Thanks for your reply. 

Where was the o ring? All I saw was a green gasket at the gas tank where it mounts. 

[Kyle]

On 5/17/2021 at 1:08 PM, Myrt Mitchell said:

Where was the o ring? All I saw was a green gasket at the gas tank where it mounts. 

Hey Myrt/Anyone else who has a similar issue. 

My machine would sometimes start and run for a few seconds, but die shortly after. Changing the fuel injector helped a bit, but chasing far too many other parts to find this... 

The o-ring this guy is referencing is between the fuel pump itself, and the plastic "pump assembly" within the tank. If you take the assembly out and look where the actual pump connects to the white plastic, you'll probably see the o-ring extruded out of place a little bit (see pic)

If you take the fuel pump assembly out, pop the cap off the bottom of the assembly by gently prying the clips. Slide the pump out (again, carefully as the wires look pretty dainty). Then slide the plastic ring, and you'll be able to either re-seat the o-ring, or just replace it if it was crimped like mine was.

Screwing the fuel pump assembly back into place was the hardest part -- gotta get that gasket perfect as rain seems to be funneled directly to the top of the assembly...

[MyCanAmSucks]

My O-ring expanded, reducing fuel pressure and had same symptoms at about 2yrs and 90hrs.  If you have the exact O-ring, that may fix, but I didn't, so I added a smaller/thinner O-ring which did the trick, but now 60hrs later, repeat symptoms.  The first time I took it apart, I saw it was a bad design destined for failure.

The Rotax is a small airplane reliable engine and CanAm messed it up!

If yours has these symptoms, disconnect fuel line and turn key, it may come out fast, so extend hose into a gas can.  Of course low or no fuel flow. but hear the pump, it's the freaking O-ring!