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Unread 08-22-2005, 12:41 PM   #1
Alfons
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Startup RPM

When I first start my '91 YJ it runs at about 1200 - 1400 rpm for a few seconds and then settles on a normal idle. I've heard of the same problem on jeeps with carbs, so it can't be the injection system - I've thought of a couple of possibilities like the throttle position sensor and the idle step motor. Any suggestions?

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Unread 08-22-2005, 12:43 PM   #2
Why J?
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mine has always done that i thought it was normal operation.
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Unread 08-22-2005, 12:49 PM   #3
atomicmoose
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that actually seems normal to me. Do you pump the pedal before starting it?

What are the engine specs on your jeep?
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Unread 08-22-2005, 01:01 PM   #4
rsoffar
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mine does that every time i start it cold but after it warms up and say i make a quick stop it wont do it then.
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Unread 08-22-2005, 01:02 PM   #5
zolon
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I would imagine that being normal, as every car I have owned did that. From my understanding it is the buildup of pressure in the fuel system. It does it on purpose for cold starts.

Could be wrong though.
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Unread 08-22-2005, 01:38 PM   #6
that_1_guy
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Same as everyone else: Mine has always done it.
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Unread 08-22-2005, 04:39 PM   #7
Alfons
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Thanks for all your input - the explanations sound logical so I guess I'll stop looking for a "fix"

Is it also normal for a 4.0 Liter Fuel Injection Engine to need several turns (4 to 6) before starting? I had thought this may have been part of the "higher startup rpm" situation, but obviously not.
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Unread 08-22-2005, 04:41 PM   #8
zolon
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Depends. Some days my dad's I6 will start when he just taps the keys. Other days it takes a few turns.

I think it's the weather to be honest. My 4 squirrel banger is the same way.
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Unread 08-22-2005, 06:53 PM   #9
kimvansa
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seems normal like they all said, I get this when you nearly stall on hill climb pull aways, still trying to get used to the foot rear brake thang, release clutch and accelerate all 2gether (thats 3 feet to me I still only got 2! so whats the trick?)
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Unread 08-22-2005, 06:56 PM   #10
kimvansa
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Quote:
Originally Posted by kimvansa
seems normal like they all said, I get this when you nearly stall on hill climb pull aways, still trying to get used to the foot rear brake thang, release clutch and accelerate all 2gether (thats 3 feet to me I still only got 2! so whats the trick?)
b4 you all come back with its a hand release now and again i need those 3 feet!
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Unread 08-22-2005, 09:48 PM   #11
TellyDSP
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Mines done it ever since I swapped in the 4.0 TB.
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