04 XTI cutting out

[BlindSquirrel]

This issue has me pretty stumped on my dad's bu. 04 XTI with the indmar 350 and ~350 hours on it. The engine runs great when you rev it in neutral, but if it is under load it will randomly cut out for about a half second when accelerating then carry on as if nothing happened. It does it multiple times during heavy acceleration even making it difficult to pull a slalom skier up if you hit the throttle hard. So far I've change the plugs, wires, cap and rotor, fuel pump, cleaned the pump screen, and fuel filter (only could find one, the silver can one before the pump, my SSVLX has 2). Yesterday I installed the newly cleaned and rebuilt fuel injectors with no real noticeable change. Do I remember reading about a fuel regulator on these engines? My boat runs strong so switching parts between the two is no problem to help identify a bad component. I'm going to jump the kill switch as a long shot before the next test, but I don't think that is the issue. The cut out RPM value is not consistent. Any direction?

 

[BlindSquirrel]

I cleaned the fuel pressure sensor screen today, it was dirty, and took the boat out. Still not the issue, here is a video I took on the lake. This is going to full throttle and holding it there. Is there a throttle position sensor somewhere? My acura did something similar and that ended up being the issue, but not sure if it is a similar system.

 

[MadMan]

Does it happen when you are moving throttle, or other times also?

[BlindSquirrel]

2 hours ago, MadMan said:

Does it happen when you are moving throttle, or other times also?

If I understand the question, if you put it at full throttle it cuts out, you can ease the throttle all the way up not miss.

[MadMan]

8 minutes ago, BlindSquirrel said:

If I understand the question, if you put it at full throttle it cuts out, you can ease the throttle all the way up not miss.

I could be the throttle position sensor then because one of it's main functions is sensing changing throttle position.

[BlindSquirrel]

Nope... just got her off the water with a brand new one. No change

[BlindSquirrel]

I think we found the issue. I put a known good fuel pump off my boat on and noticed it was whining a little, which it does not whine while hooked up on mine. That led me to believe the pump is not getting the fuel it needs to keep up. I hooked up a new fuel line to the pump and ran it directly to the fuel tank through the fuel gauge sender hole. The whine stopped... Pretty sure this tells me there was a blockage in the fuel line or the newer filter we installed wasn't flowing as it should. The way the fuel line is ran, I could see where it could kink a little, it follows the bottom of the boat and kind of turns hard right past the muffler on the port side. With an older hose, a partial kink is very much a possibility. Lake test tonight, but have a pretty good feeling it is fixed. 

[Jpeak]

I actually had this problem as well. It turned out that my fuel line was deteriorated and the interior wall of the line had collapsed and wasn't allowing enough fuel to run through the line. I did end up needing a new fuel pump a few months later though.

[BlindSquirrel]

Good deal. We have an extra pump now, so if she lets go.... no sweat. 

[BlindSquirrel]

Heck yeah!! The new fuel line and filter fixed it. Must have had ethanol in the gas at one time. Runs great now.  

[Chaabo]

Awesome!

My 2010 Response does that for some reason when it's low on fuel (less than 10%).

[Jpeak]

Glad you got were able to fix the issue!