Polaris MSX 150 Rebuilt

[Ratrace]

OK starting a new thread for this rebuilt.
Everything with the rebuilt went smooth. NOW! Started the engine and it fired right up. shut it down to check all fluids fired it up again. it started fine then just shut down after 30 seconds. restarted and it ran very rough and even sounded like intermittent small back fires. checked the fuel and it was bad. really bad ( stupid me). cleaned out the fuel and installed a new fuel filter. pumped the fuel at the rail till it ran clear. restarted the engine and still running rough with intermittent hiccups. is it possible I got the timing wrong?

[hill160881]

Make sure the map sensor plugs are not reversed. The one on top needs to have four wires on the plug. The one on bottom has three I believe.

[ripcuda]

Wait... is this your ski that you flooded yesterday... and now have the oil indicator showing on the display? I'm getting confused.

I think even one cam chain link off on the cam... and it would run pretty bad. But tell us how you set cam to crank timing... and we can probably ease your concerns.

Cheers!

[Ratrace]

No this is a new ski I'm working on. Timing was set with single dots facing each other and the front cam lobes as level as I can

[Ratrace]

Both sensors have 4 pins

[ripcuda]

Ah... okay... 2 separate MSX 150. Gotcha.

Your cam/crank timing sounds spot on. Don't fret it.

Both MAP sensors are identical. The connectors that plug into them though are different. The hardpipe MAP has a 4 wire connector (it reads air temps too). The intake MAP has a 3 wire connector (pressure only). And they are close enough to possibly mix up the wiring connectors. Worth confirming they are not crossed.

So bad gas, huh? New fuel filter and fresh gas should rule that out... unless the fuel pump is dying and pressure is low. Could be worth a check. You could also pull fuel rail w/ injectors and stick the injectors in rags or little cups and try to start it. Ensure both injectors are spraying well... not clogged. Be safe around gas.

Did you perform an ETB relearn? Could be out of sync throttle ECU mapping... could make for some weird idling running issues.

Cheers!

[hill160881]

You will need to pull back the shield and expose the wires going to a plug to see which one is 4 wire and which one is three. Both will have four pins in the plug.

[Ratrace]

confirmed 3 wire to upper intake sensor. cleaned the injectors. here is a video of the engine running. you can hear a wooring sound from the engine and intermittent pooping the it stalls at the end. cant thing of what else to look for??????

[hill160881]

The 4 wire should be up top and the three wire on the bottom.

[ripcuda]

ETB Relearn done?
Possible ETB leak at the boot on the intake... could cause hunting idle.
4-wire connector goes on hardpipe MAP
Could be bad O2 sensor... idle, low-rpm fueling issues
Could be fuel pressure... should check

Cheers!