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Unread 08-30-2012, 03:14 PM   #1
87manche17
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1987 MJ Comanche 
 
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Location: Harlan, Kentucky
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Hard starting problem, need help

Ok, Im having some wierd trouble out of my MJ. It takes it forever to start, it trys to start but to no avail. When it does start it runs perfect, and doesnt have any problems whatsoever. I have good fuel pressure, good spark, and air. But now when I unplugged my MAP sensor it tried to fire, and it fired up. I had to feather the gas pedal to keep it running, but it ran. So Im kinda wonderin if my MAP sensor is bad, or is thier something I havent though of.

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Unread 08-31-2012, 01:39 PM   #2
newfieZJ
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I would think your fuel lines are draining back into your tank . Check valve Map sensor might have been plugged back in right after it was running ?
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Unread 08-31-2012, 03:50 PM   #3
87manche17
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I have changed the battery for a new one and it starts, but im still having trouble. Because I have to press the gas pedal to get it to start.But once started its fine. WTF?
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Unread 08-31-2012, 05:25 PM   #4
cruiser54
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Gas pedal have to be pressed to the floor?
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Unread 08-31-2012, 05:42 PM   #5
87manche17
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Yep, if I dont it will crank all day.
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Unread 08-31-2012, 06:19 PM   #6
cruiser54
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Check the hose to the MAP sensor from the throttle body. Can't be crushed, crimped, cracked or split. Must fit tightly on both ends. Make sure the electrical plug to the MAP is seated tightly.
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Unread 08-31-2012, 07:28 PM   #7
87manche17
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Ive checked it 3 or 4 times thier both connected fine. It woulndnt be faulty would it?
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Unread 08-31-2012, 07:36 PM   #8
cruiser54
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The MAP? Sure could be. I just always check the simple stuff first.
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Unread 09-01-2012, 06:09 AM   #9
87manche17
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Ok thanks, I'll get back to ya when I change the MAP sensor.
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Unread 09-01-2012, 06:16 AM   #10
cruiser54
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Got a meter and know how to use it?
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Unread 09-01-2012, 09:01 AM   #11
87manche17
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Ok now it only starts if its warm outside. If i try to start it in the morning, it will just crank and catch.
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