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BluegrassBill's avatar
BluegrassBill
Explorer
Jun 10, 2015

1995 Chevy 454 intermitant hard to start

I have owned my 1995 Itasca 29 since 2002. It has 73,000 miles on it now. The engine has always been easy to start. Now It randomly is hard to start. Cranks strong but nothing, After cranking and cranking it will fire up and die unless you can catch it by pumping the throttle rapidly. Once running after a few seconds it runs normally. Goes down the road with plenty of power. I changed out the Engine Coolant Sensor, No change. I then checked the MAP sensor with a vacuum gauge and volt meter, It is within specs. The sparks plugs are new as are all wires ,coil and Distributor cap with MSD parts. The TBI is spraying fuel onto the throttle plates as it is cranking. Friends I am stumped. Any ideas. Many Thanks, Bill
Class A
  • Dachristianman's avatar
    Dachristianman
    Explorer
    Jun 10, 2015
    If there is fuel spraying into the throttle body, then it has to be ignition related. I would rule out timing because I think it would backfire with the fuel being in the cylinders when it's turning over.

    Bad ground on the engine someplace?
  • eichacsj's avatar
    eichacsj
    Explorer
    Jun 10, 2015
    Fuel pump? Could be the check valve in the fuel pump is bad and losing the prime. My 2001 had that issue.
  • jolooote's avatar
    jolooote
    Explorer
    Jun 11, 2015
    Is it fuel injected or carberated? If carberated, those old carborator fuel level floats would start to absorb fuel making them float lower in the bowl. Caused all kinds of strange starting and run problems.
  • enblethen's avatar
    enblethen
    Nomad
    Jun 11, 2015
    The fuel pump relay runs for a few seconds to prime the fuel system.
    When the engine fires and develops oil pressure the fuel pump power is fed through the oil pressure sending unit.
    Open the dog house, get down close to the left side. Turn "ON" ignition switch. Listen closely for a small click. This would be the relay dropping out. If you do not here this, the relay may not be getting power or it is bad.
    If you hear the small click, inspect your oil pressure sending unit. Look for any even small oil leak. Sending unit on mine is located on the left side of the engine toward the front near the motor mount.
  • BluegrassBill's avatar
    BluegrassBill
    Explorer
    Jun 11, 2015
    Thanks enblethen, I will check for the click tomorrow. I know where the oil pressure sending unit is but where is the relay ? I have not been hearing the fuel pump run when I turn the key on.. Bill
  • BluegrassBill's avatar
    BluegrassBill
    Explorer
    Jun 11, 2015
    Born to Travel,
    OBD1 is showing no codes. I am going to change the Oil Pressure Relay tomorrow.
    Now I'm thinking fuel pump relay. My reasoning is after cranking the oil pressure builds and the oil pressure sending unit bypasses the fuel pump relay and the engine will start.
    Bill
  • Born_To_Travel's avatar
    Born_To_Travel
    Explorer
    Jun 11, 2015
    It sounds like it could be a very lean fuel condition maybe caused by the O2 sensor on the exaust Y pipe.. You could verify this by removing a spark plug and see if it looks like it has been running very clean and hot...
  • PaulJ2's avatar
    PaulJ2
    Explorer
    Jun 11, 2015
    I also would say fuel problem. Connect fuel pressure gauge to see if it pressures up on the three second key on thing. If not suspect fuel pump relay. Pressure is 12 lbs if I remember correctly.

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