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Old 09-09-2012, 07:39 PM   #1
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hard start up when cold.

My jeep has a brand new engine , new iac,tps, new 02 sensors,air filter ,plugs,but now that it is getting colder i have noticed it is not starting right away, in fact it even slightly backfires. Anyone have any ideas what could cause this?? It is a 02 sport auto. thanks in advance.

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Old 09-09-2012, 10:05 PM   #2
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anyone please

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Old 09-10-2012, 09:45 AM   #3
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I would like to know also. Kinda having the same problem. Well mine seem to take longer and slower to start when it's cold. Maybe mines just the battery? Im not getting back fires but does that seem similar ?
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Old 09-10-2012, 09:48 AM   #4
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If you turn the key to on and waint about 5 seconds and then turn it to off and then crank it, is it any better?
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Old 09-10-2012, 06:05 PM   #5
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I will try that tomorrow morning ,its gonna be cool here again. thanks
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Old 09-10-2012, 07:23 PM   #6
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Two questions and a possible cure...

1) Does it start up right away if the engine has been running recently?

2) Does it start up more quickly if you turn the key on 3-4 times pausing 3-4 seconds between turning it back to Start? This allows the fuel pump to cycle 3-4 times before attempting to start if thereby refilling the fuel rail that the injectors plug into.

If it's yes to both, replace the Fuel Pressure Regulator that sits on top of the fuel pump. They get leaky and when that happens, the fuel drains out of the engine and back to the gas tank. The length of time it takes to restart the engine after it has been sitting for a while is how long it takes for the fuel pump to get fuel back up into the engine from the tank.

This shows a new fuel pressure regulator just before replacing the old leaky one in my TJ. The fuel pressure regulator is only replaceable separately on '04 and older TJs. On 05/06 it's part of the fuel pump so it has to be replaced as a fuel pump/fuel pressure regulator assembly.
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Old 09-10-2012, 08:34 PM   #7
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Quote:
Originally Posted by Jerry Bransford View Post
Two questions and a possible cure...

1) Does it start up right away if the engine has been running recently?

2) Does it start up more quickly if you turn the key on 3-4 times pausing 3-4 seconds between turning it back to Start? This allows the fuel pump to cycle 3-4 times before attempting to start if thereby refilling the fuel rail that the injectors plug into.

If it's yes to both, replace the Fuel Pressure Regulator that sits on top of the fuel pump. They get leaky and when that happens, the fuel drains out of the engine and back to the gas tank. The length of time it takes to restart the engine after it has been sitting for a while is how long it takes for the fuel pump to get fuel back up into the engine from the tank.

This shows a new fuel pressure regulator just before replacing the old leaky one in my TJ. The fuel pressure regulator is only replaceable separately on '04 and older TJs. On 05/06 it's part of the fuel pump so it has to be replaced as a fuel pump/fuel pressure regulator assembly.
#1 starts right away after being started for the first time.#2 will try that tomorrow morning, and another member said to try that also. Mine is a 02 is the regulator separate from the fuel pump??
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Old 09-10-2012, 08:36 PM   #8
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Quote:
Originally Posted by mrbat23

#1 starts right away after being started for the first time.#2 will try that tomorrow morning, and another member said to try that also. Mine is a 02 is the regulator separate from the fuel pump??
Yes, separate
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Old 09-10-2012, 08:41 PM   #9
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Is there a particular brand i should look for ?? I know jeeps are finicky on what parts we use.
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Old 09-11-2012, 05:25 AM   #10
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If I had to replace that part, it'd definitely be bought from the dealership
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Old 09-11-2012, 05:53 PM   #11
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Well the key thing worked so i guess i need a regulator . My question is how hard of a job is that, and should i replace fuel pump also since i'm there already and it has 130.000 miles on it ??
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Old 09-11-2012, 05:55 PM   #12
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I'd just replace the FPR.
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Old 09-11-2012, 06:02 PM   #13
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I need to do mine also, just not ready to tackle the tank drop

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