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rod
Dodge Dakota
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3/02/2004
20:28:02
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 Subject: hard starting 1993 5.2
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I have a 1993 5.2 dakota having a hard starting problem only when it sits for more than 5 hours. I have put a map sensor, I.A.C., temp sensor, spark plugs,cap, rotor,fuel filter plug wires, and a coil.and the fuel pump is 2 years old.
I have checked the fuel pres and its right at 38-39 psi and it stays there for about 1 hour and drops off slowly and was down to 15 psi after 2 hours. but right when I turn the key on it comes right up to 39 psi. the only way it will start is if you put you foot on the gas about 1/4 of the way, if you dont do this it will just crank and will not start. after it starts the first time it will start right off..how long should the fuel pres. stay at 39 psi? anyone got any ideas? thank you..
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disaster
Dodge Dakota
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3/03/2004
12:45:05
|  RE: hard starting 1993 5.2
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the fuel pressure should stay at the spec'd PSI for a long time after the pump runs initially provided that the truck is not running (no fuel passing into the cylinders from the injectors). the presure relief valve and the regulator are designed to hold the fuel pressure for extended periods. i can't remember the time the shop manual claims that the pressure must remain at the spec'd level to claim the fuel pump, regulator, & relief valve are "good" - but you're clearly there. i'm not sure what the PSI should be for your year truck. i believe my '97 is 48 PSI. but it sounds like you have plenty of pressure.
if you have to open the throttle plate to get it to start it sounds like an air/fuel mix problem. or just starved for air. if it only starts the 1st time by opening the plate it sounds like its rich (too much fuel for the available air). this assumes that the injectors are working properly at 1st.
it could also be the injector timing control. the injectors are turned on for a brief period over a specified time interval to provide fuel. this "pulse" varies according to engine demand controlled by a computer. shorter pulses for light loads/idle (less fuel), longer pulses for higher loads (more fuel). something could be preventing a pulse at start-up after sitting for a while. but i have no idea what.
the fact that the pressure holds when not running means that the injectors aren't leaking.
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rod
Dodge Dakota
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3/03/2004
22:08:08
|  RE: hard starting 1993 5.2
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could the pick-up coil be problem?
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