lean bank 1 and 2

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Jul 5, 2010 | 07:45 PM

fatboyreyn

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lean bank 1 and 2

my f150 2000 v-6 is throwing bank 1 and 2 lean codes, also fuel pressure drops off as soon as key is turned off. I replaced the fuel regulator to no avail. Checked fuel lines, and found no leaks. Replaced fuel filter.Just ordered a set of injectors. Truck has 109000 miles. Cleaned the maf sensor when I had it apart to change regulator, and didn't notice any cracked vacuum hoses. MPG is down the tubes. Truck runs and starts fine. No smoke out the exhaust. Any help would be appreciated.

Jul 5, 2010 | 08:32 PM

93 mix 'n match

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From: Montague, NJ

possibly pump?

Jul 5, 2010 | 11:20 PM

Ron W.

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From: Stockton Ca.

Quote:

Originally Posted by fatboyreyn

my f150 2000 v-6 is throwing bank 1 and 2 lean codes, also fuel pressure drops off as soon as key is turned off.

If P0171 and P0174 check your PCV line the rubber boot that attaches to the back of the intake would be a good suspect. As far as your fuel pressure dropping when the key is turned off, why would it need to stay energized?

Jul 6, 2010 | 12:36 AM

Torky2

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Quote:

Originally Posted by Ron W.

. As far as your fuel pressure dropping when the key is turned off, why would it need to stay energized?

For FI vehicles, it is important for the fuel rail to stay pressurized when the engine is turned off to avoid gas vapor bubbles forming in the fuel system underhood (vapor lock). Keeping it under pressure prevents that. The pressure should only slowly bleed down, like an hour(s) or more. That long time interval allows the engine, and underhood temps, to cool off.

Another possibility of premature fuel pressure bleed-down can be the check valve that is part of the fuel pump assembly. If it is not closing tight when the pump shuts off, then the pressurized fuel in the line to the engine can escape backwards through the stopped pump, into the tank.

Jul 6, 2010 | 02:10 AM

powersmoked

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From: Boston, MA

i agree,check valve, I assume it is in the pump. throw a large bottle of techron n the tank. did you do koeo, koer, and reomove the vacuum line when doing the pressure test.

Jul 10, 2010 | 08:18 AM

fatboyreyn

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yes. I changed regulator, checked pressure with and without vacuum line connected. I just changed all the injectors. Truck has 106000 mls. Going thru all vacuum hoses as I re assemble. I let you know the outcome. Thanks for your responses

Jul 10, 2010 | 12:29 PM

nolajefferson

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I had the same problem with my truck same year 4.2 liter V6 and everything. There is a elbow shaped formed vaccum tube that goes from the throttle body to the intake manifold. It is probly the culprit. I went to the dealer to get the part and he had a whole box of them right under the counter where he was sitting. He said they sell alot of them. Hope this helps ya...