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Old 08-13-2006, 04:29 PM   #1
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Default IT'* BACK p0171 nooooooooooooooooooo!

It came back lastnight and I am PISSED! first things first I ran out and bought a fuel pressure tester and bam 44psi. This is only 4lbs bellow minimum spec can that little cause serious problems? I'll definately baby it until I can figure this out. I was just wondering what all should I check before saying it'* just a weak pump? thanks again.
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Old 08-13-2006, 11:25 PM   #2
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This is the information on your code....

To provide the best possible combination of driveability, fuel economy, and emissions control, a closed loop air/fuel metering system is used. While in closed loop, the PCM monitors the HO2S 1 signals and adjusts the fuel delivery based upon the HO2S signal voltages. A change made to the fuel delivery will be indicated by the long term and short term FT values, which can be monitored with a scan tool. Ideal fuel trim values are around 0 percent . If the HO2S signals are indicating a lean condition the PCM will add fuel, resulting in fuel trim values of more than 0 percent . If a rich condition is detected, the fuel trim values will be less than 0 percent, indicating that the PCM is reducing the amount of fuel delivered. If an excessively lean condition is detected on bank 1, the PCM will set DTC P0171. The PCMs maximum authority to control long term fuel trim allows a range between -20 percent and +20 percent . The PCMs maximum authority to control short term fuel trim allows a range between -20 percent and +20 percent . The PCM monitors fuel trim under various operating conditions (fuel trim cells) before determining the status of the fuel trim diagnostic. The fuel trim cells are as shown on the illustration.

The vehicle may have to be operated in all of the above conditions before the PCM determines fuel trim status. The amount of fuel trim deviates from 0 percent in each cell and the amount that each cell is used directly affects whether or not the vehicle must be operated in all of the cells described above to complete the diagnostic.


DIAGNOSTIC AIDS
Check for the following conditions:

* The HO2S pigtail may be routed incorrectly and contacting the exhaust system.
* Ensure that the PCM to engine block grounds are clean, tight, and in the proper locations. Refer to Ignition Switch and PCM Signals in Engine Controls Schematics.
* The fuel system will go lean if the fuel pressure is too low. The PCM can compensate for some decrease. However, if the fuel pressure is too low, a DTC P0171 may be set.
# Check for the following vacuum leak conditions:
# Any disconnected or damaged vacuum hoses, refer to Emission Hose Routing Diagram.
# An incorrectly installed or malfunctioning crankcase ventilation valve, refer to Crankcase Ventilation System Inspection. See: Emission Control Systems\Positive Crankcase Ventilation
# Any vacuum leaks at the throttle body, the EGR valve, and the intake manifold mounting surfaces
# Check for exhaust leaks that may cause a false lean condition to be indicated. An exhaust leak may cause outside air to be pulled into the exhaust gas stream past the HO2S, causing the system to appear lean. Refer to Exhaust Leakage (Not OBD II) in Engine Exhaust. See: Engine, Cooling and Exhaust\Exhaust System\Testing and Inspection
# Disconnect the MAF sensor and see if the lean condition is corrected. If so, replace MAF sensor.
# Fuel contamination-Water, even in small amounts, can be delivered to the fuel injectors. The water can cause a lean exhaust to be indicated. Excessive alcohol in the fuel can also cause this condition. Refer to Alcohol/Contaminants-in-Fuel Diagnosis. See: Component Tests\Alcohol/Contaminants-in-Fuel Diagnosis
# A faulty connection at the PCM-Inspect the harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and faulty terminal to wire connection. Use a corresponding mating terminal to test for proper terminal tension.
# Inspect the wiring harness for damage. If the harness appears to be OK, observe the HO2S 1 display on the scan tool while moving connectors and wiring harnesses related to the engine harness. A change in the display will indicate the location of the malfunction.
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Old 10-07-2006, 10:27 AM   #3
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Thanks for the the info Archon! Sorry for the delay in response I just moved and have dealt with too much crap to even think about BC. I know I had many of you shaking your heads at testing the fuel pressure right off the bat. I did because I was pretty certain with what I went through to eliminate this code the first time fuel pressure was the prime suspect. It was a lucky guess (educated guess). I changed the pump with a brand new delco scored on ebay NIB for $150 and got the lock nut wrench for $15, think I did pretty good ALL I have to say is holly crap this woke my car up, especially up top.
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Old 10-07-2006, 10:45 AM   #4
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did you end up replacing the battery cable that is more than likely corroded from the craked battery case?
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Old 10-07-2006, 10:56 AM   #5
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no I havent changed it. when I replaced my battery which actualy caused the code to begin with the first time around due to a post that was leaking from the inside out. I cleaned the cable very well and gave a coat of dielectric grease and also changed the bolt for a new one.

EDIT: The pump has probably been in for at least a month an have hade no sign of the code. and the cable is in excellent condition I cut back into the cable and it'* all good.
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