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93' 3.9 Ignition issues

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Old 12-19-2011, 09:57 PM
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Default 93' 3.9 Ignition issues

After searching and lurking i havn't seen anyone else having the issue I've got. Any of you with the old boat anchor 3.9 Magnum may notice the slight whine/priming sound from under the hood when the ignition is kicked without starting it right off. This sound has been made every time the truck started for 207k miles, now it quit, and I am having ISSUES, the kind leaving me on the side of the road type..Have sparatic fuel pressure, sometimes it starts right up like nothings wrong, still lacking that priming sound, other days it won't start for anything, won't even start with ether. Only guesses I have at this point is maybe a sylinoid on the throttle body or the fuel pump relay. Anyone ever have this happen? Side note when I got left stranded by my truck, it ran fine then just died while cruising, couldn't restart even with ether. Just finished cleaning the Idle Air Control Motor/Valve, New Plugs. Getting ready to pull my hair out, anyone got ideas? Anything is helpful at this point.
 
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Old 12-19-2011, 10:16 PM
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You check the "notorious" splice? There is a write-up in the FAQ.
 
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Old 12-19-2011, 10:20 PM
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The splice has also been checked and suprisingly not dirty or corroded at all, main problem I know something is wrong is LACK of certain ignition sounds. It will crank till the battery dies but not fire unless fuel is dumped into the trottle body, then it runs just fine till it shuts off.
 
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Old 12-20-2011, 01:26 AM
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Sure sounds like a bad fuel pump, since pouring in fuel makes it run. A bad fuel pump can be sporadic.
 
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Old 12-20-2011, 10:08 AM
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I have considered that possibility, seeing as my fuel guage has been wacky for a long time now. Although it is a little odd for it to fail when I won't have pressure until I get the truck started by dumping gas into the throttle body, then it runs all day long no issue. Also 1 off-topic question, if I swap up to a 5.9 Magnum OBD1 with the A518 trans, would I only need to replace the drive shaft that goes from the tailshaft to the carrier bearing?
 
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Old 12-20-2011, 11:33 AM
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Some progress now, tried cold starting, to no avail. Not hearing the fuel pump kick when the ignition is turned on cold. After dumping gas down the throttle body to get it to start the die, dump again and start, rev up a little, then idles just fine like nothing is wrong. Shut off, turn ignition over again and now hear the fuel pump kick. Still lacking the whirring/whine under the hood from ignition. Thoughts?
 
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Old 12-20-2011, 07:06 PM
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SOLUTION FOUND! testing and testing and testing..relay was fine, fuses fine, wires fine, bad fuel pressure regulator. That little $74 sucker causes the engine to die at speed cruising, and be a returning problem. My unit lasted about 207k miles, so my advice to anyone else with this issue, check that thing if you start running rich, or have give/bogging/normal running patterns while driving or under load if your up around 175k and up. Hope this helps some of you guys.
 
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Old 12-22-2011, 09:14 AM
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well turns out this is probably fuel pump..now comes the fun part of getting extra hands to help lift the bed! Also, on the 3.9 Mag what all under the hood will make noise when the ignition is turned on? Trying to go process of elimination to see if I still have something wrong up top.
 



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