Fuel pump issue?

[fourbarrel]

'19 SRX all stock and yesterday it started backfiring and hesitating for no real reason. Was working like a champ until our group fueled up then a couple miles down the trail it started hesitating and backfiring.My sled was the only one doing this out of 12 so I wasn't sure what to think. I added gas line antifreeze,didn't help, then later I added some octane boost,also didn't help. The engine would run somewhat normal if I didn't push it,up to about 45 but any large throttle opening just resulted in it falling on its face and backfiring. One thing I noticed was after each rest stop the backfiring and hesitating was not as prevalent until the engine was running for about 5 minutes or so down the trail. I am going to pull the pump today and see if anything is visually wrong like a pickup line off or plugged filter. But would a pump going bad act like I have described?

 

[sideshowBob]

Was it overheating? It almost sounds like limp mode.
Also check your fuel tank vent as that would cause fuel starvation if it is not allowing the tank to "Breathe"
Throttle cable too tight causing Tors to kick in?

 

[no1b4me]

What I would recommend is drain all the fuel and get a known good supply of fuel and retest for this condition.
Though you were the only one of the group experiencing this condition after fuel up, was it delivered all through the same pump.... We're you the last sled to fill up, also you stated that as time went on this condition became less prevalent. I would only put a 1/4 tank of known good fuel, test and monitor. At least you can rule out a mechancial/electrical issue, then at this point I would empty the tank, remove the pump assembly for inspection and cleaning and also inspect and clean the tank as there maybe residual contaminates lingering within the tank.

 

[fourbarrel]

Was it overheating? It almost sounds like limp mode.
Also check your fuel tank vent as that would cause fuel starvation if it is not allowing the tank to "Breathe"
Throttle cable too tight causing Tors to kick in?

Negative on the limp mode,and I actually cracked the fuel cap a couple of times when it was acting up but it made no difference.Assuming the TORS acts the same as on the old 2 stroke by limiting the engagement,this is not that.

 

[Hammer70]

I would check plugs first how many k on sled ?

 

[fourbarrel]

What I would recommend is drain all the fuel and get a known good supply of fuel and retest for this condition.
Though you were the only one of the group experiencing this condition after fuel up, was it delivered all through the same pump.... We're you the last sled to fill up, also you stated that as time went on this condition became less prevalent. I would only put a 1/4 tank of known good fuel, test and monitor. At least you can rule out a mechancial/electrical issue, then at this point I would empty the tank, remove the pump assembly for inspection and cleaning and also inspect and clean the tank as there maybe residual contaminates lingering within the tank.

Draining the gas was actually my first thought and will try that before tearing the tank apart.I was the first one to gas up on the opposite side of a pump from another guy and he had no running issues like what I experienced.The condition never really got less prevalent,I only started noticing it wasn't happening immediately after starting up the engine but it took a 5 minutes or so of running for the backfiring to come back once letting the sled sit for a bit.

 

[fourbarrel]

I would check plugs first how many k on sled ?

One of the other guys on the ride with me actually had mentioned his sled had a pretty similar issue and it was the plugs.The sled has around 6500 km on it.

 

[no1b4me]

Draining the gas was actually my first thought and will try that before tearing the tank apart.I was the first one to gas up on the opposite side of a pump from another guy and he had no running issues like what I experienced.The condition never really got less prevalent,I only started noticing it wasn't happening immediately after starting up the engine but it took a 5 minutes or so of running for the backfiring to come back once letting the sled sit for a bit.

If you have a couple clear containers, I would pump some out in them for a visual for water /contaminant......the fuel would be my initial suspect since the sled was running like a "champ" prior to refueling.

 

[sideshowBob]

I suspect fuel as well as it was the refuel stop that seemed to be the trigger for the issues.
Years ago our group stopped at a unfamiliar fuel station and two of our riders actually refueled from a diesel pump as it was not obviously marked and the fuel refill nozzles were the same color on all the fuel pumps!

 

[rev them up]

Drain the fuel and clean/replace the fuel socks. Dirty fuel strainers was my issue, fall on its face and backfire at wfo, upto 3/4 throttle was fine. Replaced the fuel sock on the pump runs like a champ.

 

[Kenneth Rogers]

Map sensor? Could also be moisture in one or More of the small sensor lines running to the nose of the sled.