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smlein 10-16-2011 07:35 PM

2004 TJ Sport, slow start when cold
Looking for answers, any ideas are appreciated...

My 2004 TJ Sport has trouble starting when cold. It cranks a couple of times before turning over. After running for a bit, if i don't let it sit for too long, it starts up quick, no problems. It was throwing an engine light and a P0301 code.

Per previous research and advice, I just replaced the entire fuel pump assembly module (which i'm told includes the fuel pressure regulator). then disconnected the battery for a bit to reset the code.

The jeep's running smoother (so there was probably a fuel pump problem too), but the slow start issue remains.

Anyone have an idea on what it could be? O2 sensor? the fuel pressure regulator on the fuel rod? spark plugs? Fuel injectors?

Thanks for the advice.

smlein 10-17-2011 02:34 PM

Some additional info... The slow start can be avoided if I the key to ON a couple of times before I try to start. That was the reason it was advised I replace the fuel pump module with the pressure regulator on top. Thanks again for any advice you have.

00tj2 10-18-2011 03:43 PM

If its not the battery then that sounds. Ike a fuel pump problem.... You must be loosing pressure in the system and it takes the additional crank time to build up the pressure again.... That's basiclly what you are doing by turning to key to on then off a couple of times.... I think you can hook up a furl pressure gauge to the fuel rail to get a reading.... Hook it up, start the jeep to get the pressure reading then park it for the night.... Check the reading in the morning and see if and how much it dropped... I think that souls work but I'm sure others with a little but more info will chime in soon...

smlein 10-18-2011 07:42 PM

fuel pressure test
Battery is good, replaced in the last 6 months or so, and no other signs of electrical. I think you're right, it must be fuel pressure issues. Need to confirm and then figure out where the loss is coming from.

Any idea where to hook up a fuel pressure gauge on an '04 I-6?

My mechanic and I took a quick look after replacing the fuel pump didn't work, and couldn't figure it out. He' thinking we may need to cut into the link to add a place to connect... which I'd really rather not have to do.


smlein 10-20-2011 11:13 PM

Random update: Still slow-starting, but the engine light is no longer on. /boggle

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