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Ramblin__Rosie's avatar
Ramblin__Rosie
Explorer
May 07, 2019

Engine will not start (2006 Chevy Express 3500 chassis)

We have a 2007 Winnebago 331C Motor Home with a 2006 Chevy Express 3500 chassis (6.0 L V8 gas engine). We cannot get the engine to start. Here is a summary of what we have done, along with some hypotheses:


Problem

The starter cranks the engine with no problem, but it will not start. The engine will sputter briefly, but will not fire. We just got back home from a 1,400 mile round trip to Washington DC. The oil pressure light went on and off briefly a few times (it was on for a few minutes each time). Checked the oil a few times during the trip, it was full each time. The oil pressure gauge never went too high or too low.
Aside from the oil pressure light, we did not notice any problems during this trip. The first time we tried to start the engine after we got back home (the next day,) it would not start.

Things we’ve done

- Scanned for OBD codes several times with two scanners. No codes found.
- Inspected/cleaned the mass air flow sensor (did not replace it.)
- Replaced all spark plugs, wires, and ignition coils.
- Replaced the crankshaft position sensor.
- Checked fuel pressure at engine, 55psi (minimum limit, per the Haynes manual).
- Checked grounding wires/straps from the chassis to the engine.
- Looked for various fluid leaks. None found.

-------------------------------------------------
Possible Causes?

- Bad fuel?
- Clogged injectors?
- PCU problem?
- There is an “AUX START” switch on the driver’s side kick panel, below and to the left of the steering wheel. I damaged this switch when I removed the panel. This is a momentary switch which connects the motor home’s marine batteries to the vehicle’s electrical system, so the marine batteries can be used to start the engine, if the vehicle’s battery is dead. Is it possible that this switch needs to be assembled and in place to start the engine?

We welcome and and all advice! Thanks in advance!
  • Ramblin__Rosie's avatar
    Ramblin__Rosie
    Explorer
    May 08, 2019
    That was the first thing we we tried, as a matter of fact. It did not seem to help with the problem.

    MDKMDK wrote:
    Will it start if you press the gas pedal to the floor while cranking? I had a similar problem on a 2002 5.7L Vortec. I think it was described in the owners manual. Think it cleared excess fuel from the cylinders from repeated crank no start.

    From the 2002 Chevy Express owner's manual
    "NOTICE:
    Holding your key in START for longer than
    15 seconds at a time will cause your battery to
    be drained much sooner. And the excessive heat
    can damage your starter motor. Wait about
    15 seconds between each try to help avoid
    draining your battery or damaging your starter.

    2. If it doesn’t start within 10 seconds, push the
    accelerator pedal all the way to the floor, while you
    hold the ignition key in START. When the engine
    starts, let go of the key and let up on the accelerator
    pedal. Wait about 15 seconds between each try.

    When starting your engine in very cold weather
    (below 0F or -18C), do this:
    1. With your foot off the accelerator pedal, turn the
    ignition key to START and hold it there up to
    15 seconds. When the engine starts, let go of the key.

    2. If your engine still won’t start (or starts but then
    stops), it could be flooded with too much gasoline.
    Try pushing your accelerator pedal all the way to
    the floor and holding it there as you hold the key in
    START for about three seconds. When the engine
    starts, let go of the key and accelerator. If the vehicle
    starts briefly but then stops again, do the same
    thing, but this time keep the pedal down for five or
    six seconds. This clears the extra gasoline from
    the engine."
  • MDKMDK's avatar
    MDKMDK
    Explorer
    May 07, 2019
    Will it start if you press the gas pedal to the floor while cranking? I had a similar problem on a 2002 5.7L Vortec. I think it was described in the owners manual. Think it cleared excess fuel from the cylinders from repeated crank no start.

    From the 2002 Chevy Express owner's manual
    "NOTICE:
    Holding your key in START for longer than
    15 seconds at a time will cause your battery to
    be drained much sooner. And the excessive heat
    can damage your starter motor. Wait about
    15 seconds between each try to help avoid
    draining your battery or damaging your starter.

    2. If it doesn’t start within 10 seconds, push the
    accelerator pedal all the way to the floor, while you
    hold the ignition key in START. When the engine
    starts, let go of the key and let up on the accelerator
    pedal. Wait about 15 seconds between each try.

    When starting your engine in very cold weather
    (below 0F or -18C), do this:
    1. With your foot off the accelerator pedal, turn the
    ignition key to START and hold it there up to
    15 seconds. When the engine starts, let go of the key.

    2. If your engine still won’t start (or starts but then
    stops), it could be flooded with too much gasoline.
    Try pushing your accelerator pedal all the way to
    the floor and holding it there as you hold the key in
    START for about three seconds. When the engine
    starts, let go of the key and accelerator. If the vehicle
    starts briefly but then stops again, do the same
    thing, but this time keep the pedal down for five or
    six seconds. This clears the extra gasoline from
    the engine."

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