2017 Prostar no start

LoopSkiLoopSki Posts: 964 Mega Baller
Ran fine all weekend with no problems. Went to start yesterday afternoon , no go. Checked the obvious stuff. Gas good ( put some in just in case gauge was off again ) safety lanyard good and functional, throttle centered and wiggled. Fuses on panel look good. No obvious loose connections I could find. Fuel pump primes and engine cranks after depression of start button. Screen comes up. Batttery good. Tried about 10 times. No start. There was no indication anything was going out on Sunday. On my last Mastercraft when the fuel pump went it was acting up. Not sure if the Ilmore pumps go without warning. Any thoughts? If i have to take to the dealer, i will likely lose most the spring.


  • MastercrafterMastercrafter Posts: 386 Crazy Baller
    5.7? Is it cranking for the prescribed 10 seconds before stopping, and never firing up? On the rear of the drivers side fuel rail, there is a schrader valve with a black plastic cap. Removing the cap and depressing the valve should cover your doghouse with fuel, if there is pressure. You can also attach a fuel pressure gauge there. There should be residual pressure after the fuel pump cycles, and obviously there should be pressure during cranking. 4 bar/55 psi.

    Check your crank position sensor, coil and distributor connections. Crank with one spark plug removed (and grounded) to see if you're getting spark.

    I have a Rinda Diacom setup I could ship you to try and troubleshoot before taking to the dealer.
  • MastercrafterMastercrafter Posts: 386 Crazy Baller
    edited May 19
    Also, take your flame arrestor off and look at the throttle butterfly during key-on (not start) it should open up (I think WOT, and you'll hear the high-pitched whine of the servo motor) then after a second or two, go down to about 15% open, which is its start position. Once running, it closes down to adjust/maintain idle speed.

    Long story but I had a bad ECU that never opened the throttle plate and that was the first sign something was wrong.
  • jpwhitjpwhit Posts: 220 Solid Baller
    edited May 19
    Doesn't the 7" display have an engine diag screen that shows any engine codes? I realize it's not as much info as my Diacom setup will show, but it's a start.

    Beyond that, start with the basics. Fuel and Spark. You won't have one or the other. @Mastercrafter suggestion is a good start. Another quick way to determine if it's fuel, is to get a spray can of starter fluid. One burst into the throttle body, and if it's starts for a second, then it's not getting fuel. Easy and safe way to tell if you have spark is to get a cheap spark tester. Or use a timing light if you have one. If you're comfortable doing it, you can do the old screwdriver in one of the spark plug leads that is held about 1/4 inch from a ground. But you can get zapped doing that and if there are any fumes, they can be ignited.
  • LoopSkiLoopSki Posts: 964 Mega Baller
    Disconnected the blower so I could make sure I could hear the fuel pump and it is definitely whining. Try to restart this morning and actually on the second attempt it fired up for like a second.
  • MastercrafterMastercrafter Posts: 386 Crazy Baller
    Just because the fuel pump is whining doesn't mean it's making pressure... I'd try the starting fluid test mentioned above as well.
  • LoopSkiLoopSki Posts: 964 Mega Baller
    Pushed the shrader valve, gas came out. Pushed on all connections I could find, and it fired up. So not sure wtf. Restarted a few times. Seems good. Didn’t want to take out for a spin with our high winds.
  • GloersenGloersen Posts: 1,253 Mega Baller
    if it's a 5.7 consider replacing the cap & rotor (if not recently done) with high quality parts just to rule those components out as culprits
  • chrislandychrislandy Posts: 356 Crazy Baller
    Mine wouldn't start at the beginning of the season, but that was a poor battery connection and the voltage would drop to ~7v on cranking so the ecu would shut down. It did throw a load of errors on the diagnostic screen so it might be worth just checking nothing is popping up.
  • BraceMakerBraceMaker Posts: 5,129 Mega Baller
    @LoopSki get a test gauge and verify pressure. Just spraying doesn't prove enough pressure they need quite a lot of pressure to inject properly and it matches your symptoms
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