Greetings Gurus,

I am trying to track down the cause of the P0171 code on my van. I borrowed a friend's CarChip to help narrow down the culpret and have posted the report below. I changed both O2 sensors, MAF, and fuel filter about 6 mos ago and traced & inspected every inch of all vacuum lines. In an earlier thread I posted, 96_4wdr replied (thanks 96_4wdr) stating that Bank 1 was used generically and to disregard it. However, after reading the info collected from the CarChip, I'm led to believe that there is indeed too little fuel being distributed to Bank 1 - thus the definition of P0171: System too lean on Bank 1. (Note the last two subheadings below.)

Overview
Time: 2/10/2007 8:17 AM
Vehicle: Aerostar
CarChip: J-9511-B
Trouble Code: P1443, P0171
Description: System Running Too Lean On Bank 1
Comments:

Engine Status
Fuel Pressure (Gage):
Intake Manifold Pressure (Absolute):
Engine Coolant Temperature: 177.8 °F
Calculated Load Value: 48.6 %
Engine Speed: 1,672 RPM
Vehicle Speed: 48 MPH

Fuel Trim Status
Short-Term Fuel Trim (Bank 1): -0.78 %
Short-Term Fuel Trim (Bank 2): 2.34 %
Long-Term Fuel Trim (Bank 1): 5.47 %
Long-Term Fuel Trim (Bank 2): 5.47 %

Fuel System Status
Fuel System 1 Status:
Fuel System 2 Status: Closed loop; using oxygen sensor(s)
as fuel control.

If it is indeed a fuel delivery problem, am I correct to assume it's either the injectors or fuel pump? And lastly, which side is Bank 1?

Thanks in advance for any help.

Steve

PS: I've got 'til the end of the month to make it pass emissions!

 

O2 sensor #1 in front of CAT reads emissions i.e. primary input in setting air/fuel mix for both sides of engine since the Aero is a single exhaust singe air/fuel mix O2 sensor system.
second O2 monitors CAT for failure and 1st O2 for accuracy

if you have a factory dual exhaust system with 2 primary O2 sensors in front of the CAT then there will sequential injector fuel control for 2 separate banks

look at the O2 sensor voltage reading with the scanner...you will not see a valid Bank 2 reading on an Aerostar since there is no Bank 2 O2 sensor

the Bank 2 info you are seeing on the scanner is false filler info stored by the PCM

i use both an AutoXray 4000 and an AutoTap system with my Palm....both work the same way on single exhaust single O2 fuel mix setting sensor systems

plug into an Mustang 4.6L with the dual exhaust, dual CATS and 4 O2 sensors....you will then have 2 valid banks with the PCM monitoring and controlling both

the only active valid PCM Bank sensor reading on Aero systems is Bank 1

yes, your system is running lean, both sides and all six cylinders or at least the majority....
1. partially plugged injectors, first try bottle of Chevron Techron Concentrate or Gumout Regane or Large Vehicle Fuel System cleaner, 20oz in 1/2 tank of gas, has the top gun injector cleaner, polyetheramine, all the others are worthless junk?
2. check for vac. leak with spray carb cleaner at idle, rpm increase=leak...test from MAF to heads and all vac. lines

remove neg. - batt. lead for 5 minutes minimum after each service item to clear KAM parameters so that PCM will relearn correct new power train parameters

 

Thanks for the great info and advice!! Will get to it tomorrow and post back my findings. Regarding partially clogged injectors... approx. how much does it cost to have my injectors cleaned at a shop? In the interest of time, I may not have enough to wait for the additive to do the job.

Thanks again.
Steve