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Click for Crusader parts and manuals!
Results 1 to 11 of 11
  1. #1
    Join Date
    Aug 2006
    Location
    Lakeville, IN, USA
    Posts
    198

    Default Hot engine hard start

    What causes a fuel injected (muti port injection) engine to be hard to start when it is hot? Fires up when cold in seconds, when try to start after it is at operating temp it takes four or more tries and then usually stalls once or twice before starting. It was mentioned to me that a temperature sensor could be bad???

  2. #2
    Join Date
    Sep 2008
    Location
    Maryland - USA
    Posts
    5,569

    Default Re: Hot engine hard start

    if it sits for a while once warmed up. it is termed a hot-soak and the issue's root cause is the fuel in the rail boiling.

    A bad ECT or IAT sensor can make this worse - easy to measure the sensor's resistance and compare it to a reference chart to see if it is ok.

    Best 'fix' is to prevent the "hot soak" from occurring.

  3. #3
    Join Date
    Aug 2006
    Location
    Lakeville, IN, USA
    Posts
    198

    Default Re: Hot engine hard start

    How do you prevent the "hot soak" from occurring? The rail sits on the engine obviously, no way to insulate it from the heat. What else can be done?

  4. #4
    Join Date
    Sep 2008
    Location
    Maryland - USA
    Posts
    5,569

    Default Re: Hot engine hard start

    cheapest is to cool the engine at fast idle before shutoff. open the engine room access hatch(es) can also help. adding additional mechanical ventilation isn't unusual.

    As far as spec numbers, best to consult the crusader installation manual (the current one from their www site is applicable to older models as the big issue is the fuel volatility, no the means it is delivered).

  5. #5
    Join Date
    Sep 2003
    Location
    New Tripoli, PA, USA!
    Posts
    12,501

    Default Re: Hot engine hard start

    Leaking injectors will do that as well, but there's a simple fix: Tap into the fuel line going to the injectors and install a Tee. Gas coming out of this tee goes through a tiny orifice (I solder a fitting closed, then 1/16 " drill it open) and back to the tank. In operation, some fuel will always be going back to the tank--no problem unless the orifice is too big, At shut down, however, the pressure in the fuel manifold drops immediately to zero, so injectors don't leak into the motor. Works slick!

    Jeff

  6. #6
    Join Date
    Aug 2006
    Location
    Lakeville, IN, USA
    Posts
    198

    Default Re: Hot engine hard start

    Here is kinda of a interesting quirk, my engines have return fuel lines, in doing some fuel pressure tests with Crusader engine manual in hand I found that upon shut down the pressure was dropping to zero immediately. According to the manual pressure should remain in the rail for a period of time. So I went through the process of determining where the "leak" was.. fuel pump? injectors? regulator? By process of elimination found out it was the fuel regulator, did the same on both engines so I ordered two new regulators. When they came I first put one on starboard engine, retested it and found the same drop in pressure occurred. So I called Crusader, spoke to Greg Messenger...(now no longer there) and he said despite what the manual said the immediate drop of fuel pressure is normal and offered to reimburse me for the expense of the regulators... (nice guy)... bottom line, I have no pressure in the lines once the engine shuts down. I thought the reason why fuel injected engines were less affected by "heat soak" was because of the fact the fuel remained pressurized for a while thereby not "bubbling" like a carbed engine?

  7. #7
    Join Date
    Sep 2003
    Location
    New Tripoli, PA, USA!
    Posts
    12,501

    Default Re: Hot engine hard start

    You have to ask yourself: If the pressure drops immediately to zero, where is all that fuel going? If it's back to the tank, thanks to a leaky regulator valve seal, swell! But if it's into the engine via a leaking injector(s), that's bad news for hot starting (and the rings of that cylinder).

    Jeff

  8. #8
    Join Date
    Sep 2008
    Location
    Maryland - USA
    Posts
    5,569

    Default Re: Hot engine hard start

    they are less susceptable because the fuel is injected vs being controlled by pressure. The bubbling you described is usually boiling and results in uncontrolled fuel vapors being available for injection when the engine restarts (richness).

    Personally, I'd rather have the regulator setup that Greg tagged as normal. as long as the pump builds adequate pressure when the key is turned on, and maintains it after the engine is running, the injectors will work just fine.

  9. #9
    Join Date
    Sep 2003
    Location
    New Tripoli, PA, USA!
    Posts
    12,501

    Default Re: Hot engine hard start

    Agreed, but sudden loss of pressure after shut down indicates a leak back through the regulator (good), or leaking injectors (not good).

    Jeff

  10. #10
    Join Date
    Aug 2006
    Location
    Lakeville, IN, USA
    Posts
    198

    Default Re: Hot engine hard start

    Pretty certain not leaking through injectors. Sent all sixteen of them to be tested, cleaned and refurbished last spring ('11). All were functioning properly, a couple had restricted flow that were fixed with the bench cleaning. Plus, when I had the gauge on the rail the pressure would hold if I clamped off the return line so that would lead me to believe that no fuel was leaking through the injectors. But I guess my question is, if the fuel regulator cannot hold the pressure for any period of time after shut down, then is it really doing anything? I get 39 psi at idle, manual suggests 43 psi at idle is normal, port engine gets 43 psi.

  11. #11
    Join Date
    Sep 2008
    Location
    Maryland - USA
    Posts
    5,569

    Default Re: Hot engine hard start

    I think you will find the regulator is doing what it is supposed to do.

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