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  #1  
Old 09-08-2012, 07:53 PM
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Starting prob?

My 99 4.7 is having some starting problems. Cold starts it fires right up, when it's hot it drags really bad when trying to start. Starter is good, the shop said it is a bad ground but that doesn't make sense to me... Anyone else have this problem or a solution. Thanks
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Old 09-09-2012, 07:09 AM
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Re: Starting prob?

The shop didnīt explain their reason for suspecting a bad ground? I would think that if its a bad ground, it still would be bad when cold as well.
I would think in the direction of one of the sensors, but canīt tell you how to determine which one. Did you check for any DTC set?
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Old 09-09-2012, 07:10 AM
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Re: Starting prob?

Cam sensor and fuel pump will both affect starting.
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Old 09-09-2012, 08:46 AM
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Re: Starting prob?

Mine did the same thing it was the fuel pump and/or pressure regulator.
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Old 09-09-2012, 10:33 AM
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Re: Starting prob?

No DTC's are being pulled. I'll check the fuel pump and regulator, and maybe the cam sensor. Thanks guys!
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Old 09-09-2012, 10:42 AM
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Re: Starting prob?

Mine does this very rarely, done it this morning after church actually - first time in 3 months.

Cranked over and started as normal but was idling at ~2-300rpm. Before it died, I tapped the gas and it kicked into life and idled at 550rpm again. Temp gauge was 1/4 of the way.

Can't see it being a grounding issue, fuelling would make more sense.
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Old 09-09-2012, 02:03 PM
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Re: Starting prob?

I'd put money on either the fuel pressure regulator (which is built into the fuel filter, I remember a few threads from a while ago about replacing these) or the fuel pump. However if the regulator isn't good usually it will be hard to start when cold because the fuel system will lose prime. Could be the pump acting up when hot.
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Old 09-09-2012, 06:05 PM
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Re: Starting prob?

Quote:
Originally Posted by 01grand View Post
I'd put money on either the fuel pressure regulator (which is built into the fuel filter, I remember a few threads from a while ago about replacing these) or the fuel pump. However if the regulator isn't good usually it will be hard to start when cold because the fuel system will lose prime. Could be the pump acting up when hot.
Eventhough the engine gets hot, the fuelpump is inside the fuel and shouldn't warm up. Also wouldn't believe the pressure regulator is the culprit, because then the problem is usually there during first start or even every start. Seems to me that a sensor is acting up when hot, giving the wrong information to the PCM.
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Old 09-10-2012, 05:24 AM
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Re: Starting prob?

Im starting to think its a bad ground now. I fried the ground from the PCM to the block last night. Im guessing from a different ground that is bad, it overloaded the wire. Just a guess....
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Old 09-10-2012, 09:01 AM
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Re: Starting prob?

Is there isolation on the ground wire which melted? Have a look at all the ground wire connections of the engine block. A little bit of corrosion can already cause a bit of resistance in for example the starter ground and overload other ground wires.
Still strange that the problem is not there with the engine cold though.
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Old 09-10-2012, 12:45 PM
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Re: Starting prob?

I know. The problem stumped me haha. Just basically a process of elimination now.
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Old 09-11-2012, 05:42 AM
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Do.you run your fuel.tank to E a lot or keep it above 1/2 . Only reason I ask I been told if.you run on E or 1/4 tank or.less the pump runs hotter. As less.fuel to keep it.cool.

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