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Trouble Code P.0171 HELP!!

A

acontour

CEG'er
Joined
Dec 14, 2007
Messages
245
Hi guys.
I have a 97 , Ford Contour , 2.0L , DOHC , VIN 3 and can't figure out how to get rid of (p0171 system too lean bank 1). I tried to pass emissions and failed twice. I changed: IAC ,TPS ,EGR DPFE sensor ,fuel filter , and PCV valve. I checked the fuel pressure and it's at 35. I checked spark plug wires and they all give out a spark. I really ran out of ideas.

This is my dilemma. I rebuilt the engine with Je pistons (compression went from 9 something to 10.5.1) , Eagle rods ,OEM water pump and oil pump. I have a custom high flow exhaust , and a COSMO racing short intake.
Would it have a lean code because my compression went up , therefore getting more air ? Do I need bigger injectors?

Sorry for being so long. I'm just going crazy with this car. Thanks a lot for any help.
 
You should get a real time scan (with live data and freeze frames). Advance has the Actron CP9180 on sale for $139 now. Or get a mechanic with a scanner to scan it for you (should be about $100). With the live data or freeze frames posted here, we will be able to determine better what is causing the P0171. Right now, we can only give you the standard reasons.

Edit. Per TSB, some of the causes of P0171 and P0174,

P0171 - System Too Lean (Bank 1) The Adaptive Fuel Strategy continuously monitors fuel delivery hardware. The code is set when the adaptive fuel tables reach a rich calibrated limit.

Fuel System:
· Contaminated fuel injectors
· Low fuel pressure or running out of fuel (fuel pump, filter, fuel supply line restrictions)
· Vapor recovery system (VMV)

Induction System:
· MAF contamination
· Air leaks between the MAF and throttle body
· Vacuum leaks
· PCV system concern
· Improperly seated engine oil dipstick

EGR System:
· Leaking gasket
· Stuck EGR valve
· Leaking diaphragm or EVR

Base Engine:
· Exhaust leaks before or near the HO2S
· Secondary air concern
Powertrain Control System:
· PCM concern

P0174 - System Too Lean (Bank 2) Same as DTC P0171, but Bank 2. See Possible Causes for DTC P0171
 
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well typically on a duratec a P0171 or P0172 can indicate that the O2 sensor is getting lazy and is on its way out. I would get a scanner like Tony suggested where you can watch the voltage value of the O2 sensor as the car is running to determine if its reading right.

If it is try cleaning the MAF and of course check for vacuum leaks.
 
It's not a D-tec though, it's a Zetec.

You've changed all the sensors except the O2 sensor? Was it new already from the rebuild?
 
acontour said:
This is my dilemma. I rebuilt the engine with Je pistons (compression went from 9 something to 10.5.1) , Eagle rods ,OEM water pump and oil pump. I have a custom high flow exhaust , and a COSMO racing short intake.
Would it have a lean code because my compression went up , therefore getting more air ? Do I need bigger injectors?
QUOTE]

Raising the compression doesn't increase the amount of air only increasing the cubic inches will do that (stroker crank, oversized pistons. Increased compression only compresses the existing volume more resulting in a more vigorous explosion. Shouldn't change mixture.
Click to expand...
 
Tony2005 said:
What year, mileage and tranny? Do you hear a hissing sound in the engine bay?
Click to expand...

1998 SE w/ a 2.5 MTX-75 tranny w/ 120,000 miles. We have not checked a vacuum leak, but the green hose from the EGR was broke and we put hose over it to repair the broken line, but no change we still have these codes.

Correct me if I'm wrong, but can't you use a spray bottle and spray water on certain areas around the intake and vacuum lines to see if the idle picks up to see if there is a vacuum leak?

My car has these same codes and I'm so curious.
 
OutlawdSVT said:
...Correct me if I'm wrong, but can't you use a spray bottle and spray water on certain areas around the intake and vacuum lines to see if the idle picks up to see if there is a vacuum leak?

My car has these same codes and I'm so curious.
Click to expand...
Use carburetor cleaner. And the idle changes (up or down). If one of the hoses is broken (rather than cracked), you should be able to see and hear it.
 
acontour said:
Hi guys.
I have a 97 , Ford Contour , 2.0L , DOHC , VIN 3 and can't figure out how to get rid of (p0171 system too lean bank 1). I tried to pass emissions and failed twice. I changed: IAC ,TPS ,EGR DPFE sensor ,fuel filter , and PCV valve. I checked the fuel pressure and it's at 35. I checked spark plug wires and they all give out a spark. I really ran out of ideas.

This is my dilemma. I rebuilt the engine with Je pistons (compression went from 9 something to 10.5.1) , Eagle rods ,OEM water pump and oil pump. I have a custom high flow exhaust , and a COSMO racing short intake.
Would it have a lean code because my compression went up , therefore getting more air ? Do I need bigger injectors?

Sorry for being so long. I'm just going crazy with this car. Thanks a lot for any help.
Click to expand...
your fuel pressure is a little low. it should be between 40 and 45PSI. what fuel pump do you have? it might be worth getting either an aeromotive adjustable FPR and/or a 255LPH fuel pump.

also,like was already suggested, check/replace the O2 sensor.
 
i'm on a time crunch so i broke down today and took the car to a shop. they are going to figure out the problem and i will decide from there if it's worthing fixing or not. i might end up in a cx-7 before too long! :)
 
Still trying to figure it out

Still trying to figure it out

Hi.
Thanks Tony , I will most likely go to a shop or get the Actron CP9180 . I scanned it with a basic Actron OBD2 reader and it says that the O2 sensor , HO2 sensor , and catalyst are not ready. Fuel System , Comprehensive ,and EGR system are ready. I cleaned the MAF sensor today , but still no luck. When the car is idling and step on the gas fast it chokes and almost dies , when I step on the gas slower the revs go up normal. I reset the code and came back when driving in less than 5 miles. I checked the PVC valve and it looks like it's not properly seated in the grommet , but can't hear a hissing sound.

The O2 sensors are old and haven't been changed. I will changed them tomorrow and keep you guys updated. I will also change my short air intake with the old one and see if it changes anything.
 
acontour said:
...The O2 sensors are old and haven't been changed. I will changed them tomorrow and keep you guys updated. I will also change my short air intake with the old one and see if it changes anything.
Click to expand...
Yes, change the short air intake and see if it helps. And change the Upper O2 sensor as it hasn't been changed.

Do not change the Lower O2 sensor unless you have a specific code for it. Doing so would be a waste of money.
 
striker2 said:
your fuel pressure is a little low. it should be between 40 and 45PSI. what fuel pump do you have? it might be worth getting either an aeromotive adjustable FPR and/or a 255LPH fuel pump.

also,like was already suggested, check/replace the O2 sensor.
Click to expand...

I just have a stock fuel pump. The fuel pressure is at about 35 and when I rev it up , it goes up to 40 PSI. I love you car , where did you get the turbo ? I was thinking about a garret , but its kind of expensive. Mine Contour is the California model , and has the lame EGR port in the headers. I got the svt long tube headers . Also did you have any problems with idling or accelerating when the air intake was changed on it?
 
Tony2005 said:
Yes, change the short air intake and see if it helps. And change the Upper O2 sensor as it hasn't been changed.

Do not change the Lower O2 sensor unless you have a specific code for it. Doing so would be a waste of money.
Click to expand...

Do you know what "not ready" in O2,HO2,and catalyst means when I scan it with the OBD2 reader . Is it mean that they are faulty??
On my way to get the upper O2 sensor. The one before the catalyst , right?
Thanks
 
acontour said:
Do you know what "not ready" in O2,HO2,and catalyst means when I scan it with the OBD2 reader . Is it mean that they are faulty??
On my way to get the upper O2 sensor. The one before the catalyst , right?
Thanks
Click to expand...
The PCM has to go through the OBD II cycle. Each time you disconnect the battery or remove the fuses to erase the codes, it goes to the "not ready" mode. After driving a few days, it will be ready. Or go through the OBD II cycle procedure (found in the Owners' Manual, download free from www.fleet.ford.com) to get the PCM ready. No, it does not mean that those items are faulty. If those items are faulty, you will get a code for them.

Yes, the Upper O2 sensor is the one before the catalyst (the one closest to the engine). The lower O2 sensor will be the one closest to the muffler.

Edit. OBDII cycle.
http://www.obdii.com/drivecycleford.html
 
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yes, the upstream sensor is the one just above the cat. It will be right there in front between the engine and radiator.

Bosch 13115 will be the one you'll want to get.
 
acontour said:
I just have a stock fuel pump. The fuel pressure is at about 35 and when I rev it up , it goes up to 40 PSI. I love you car , where did you get the turbo ? I was thinking about a garret , but its kind of expensive. Mine Contour is the California model , and has the lame EGR port in the headers. I got the svt long tube headers . Also did you have any problems with idling or accelerating when the air intake was changed on it?
Click to expand...
ok so your Fuel pressure does at least rise to the correct level with the throttle. good.

I had EGR on mine (i think they all did until 98 when they added VCT) but i just blocked off the tube going to the intake manifold at the EGR valve. i have it turned off in the tune. no i dont have any idle or accel issues but thats cause of the tune.


your car is going to stay in the base table mode until it goes to closed loop. it wont do that until all the checks are completed. obviously the checks for the O2, HO2, and cat have not completed. How far have you driven it since you reset the PCM?
 
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