4.7l Hard Starting - Fuel Pump?

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richardx - 07 Apr 2005 00:00 GMT

Howdy All -

Found this archived post that is pretty spot on for my problem -
http://groups-beta.google.com/group/alt.autos.dodge.trucks/browse_thread/thread/
2b6775faa48d35a0/6fac04e03b910e5a?q=4.7L+Hard+Starting&rnum=1#6fac04e03b910e5a

I moved from philly to Texas (drove) and my 01 4.7l Dakota hasn't
started on the first crank since.

The above linked post is pretty much my exact problem, right down to
the test - if I cycle the ignition (and thus the fuel pump) three-four
times without cranking, starts like a champ on the first few seconds of
the first crank. otherwise, I could turn it over forever on the first
crank and it will never start. starts on the second almost always and
sometimes the third.

Had it in the shop and the best they could tell me was that it might be
the idle air control motor. Thats allot cheaper than the fuel pump that
the other post suggested....

Anybody have any more recent experience with this? Before I drop 300 in
parts and gawd knows how much in labor for a new fuel pump wanted to
check in with y'all first... thanks in advance!

richardx

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Tom Lawrence - 07 Apr 2005 00:49 GMT

> Had it in the shop and the best they could tell me was that it might be
> the idle air control motor. Thats allot cheaper than the fuel pump that
> the other post suggested....

If it's an IAC problem, then cracking the throttle plates open a bit while
cranking (light pressure on the accelerator pedal) would alleviate the hard
starting problem.

You should check the fuel pressure in the fuel rail after engine shutdown.
There should be a test port on the fuel rail - middle of the passenger-side
rail (should be a black plastic cap that you can unscrew). Ideally, you
want to hook a gauge to this, and still read pressure 30 minutes or so after
shutting down. When you turn the ignition switch to 'ON', you should
immediately (within a second) see >45psi in the rail.

If you have low, or no, fuel pressure in the rail 30 minutes after shutdown,
you have a leak somewhere. If the pressure drops immediately upon shutdown,
the problem is in the fuel pump module (check valve). If it drops off very
slowly, then it might be a small leak in the fuel pump module, or it could
be a leaky injector (any black smoke upon startup now?). If the pressure
doesn't immediately come up with the ignition on, then it's most likely a
bad fuel pump.

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