Code because of exhaust?
09-24-2016, 09:06 PM
#1
Code because of exhaust?
I have been throwing check engine code p0171. I took it to the dealer and they are working on it. My 08 base manual had the mild to wild exhaust but I removed it and at first had the slp loudmouth but then just did a muffler delete. The dealer said that the code could be coming from the exhaust change but I don't understand why. All I did was change the axle back. All sensors are way before that. If the vacuum line that controls the NPP exhaust wasn't blocked off is there anyway that code could show up?
09-25-2016, 09:28 AM
#2
Safety Car
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Location: Pearland / Houston Tx
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This is what the shop mays states to look for with P0171:
Circuit/System Testing
P0171 or P0174
Allow the engine to reach operating temperature. With the engine running, observe the affected Long Term FT parameter with a scan tool. The reading should be between 0-19 percent.
⇒ If not within the specified range, inspect for the following:
• With the ignition ON and the engine OFF, observe the manifold absolute pressure (MAP) sensor parameter. The MAP sensor pressure should be within the range specified for your altitude. Refer to Altitude Versus Barometric Pressure.
⇒ Refer to DTC P0106 if the MAP sensor does not indicate the correct barometric pressure.
• With the engine idling, observe the mass air flow (MAF) sensor parameter. The MAF sensor parameter should be within 2-6 g/s at idle.
⇒ Refer to DTC P0101 or P1101 or DTC P0102 or P0103 if the MAF sensor parameter is not within 2-6 g/s at idle.
• Vacuum hoses for splits, kinks, and improper connections--Refer to Evaporative Emissions Hose Routing Diagram.
• Insufficient fuel in the tank
• Low fuel pressure--Refer to Fuel System Diagnosis.
• Fuel contamination--Refer to Alcohol/Contaminants-in-Fuel Diagnosis.
• Malfunctioning fuel injectors--Refer to Fuel Injector Diagnosis.
• Missing, loose, or leaking exhaust components from the HO2S forward--Refer to Symptoms - Engine Exhaust.
• Vacuum leaks at the intake manifold, the throttle body, and the injector O-rings
• The air induction system and the air intake ducts for leaks or for a missing air filter element
• A cracked EVAP canister
• Evaporative pipes obstructed or leaking
• The crankcase ventilation system for leaks--Refer to Crankcase Ventilation System Inspection/Diagnosis.
• The HO2S for improper installation and for electrical wires or connectors that may have contacted the exhaust system
• The HO2S signal circuit open, shorted to ground, or shorted to the low reference circuit
• Malfunctioning engine components--Refer to Symptoms - Engine Mechanical.
Circuit/System Testing
P0171 or P0174
Allow the engine to reach operating temperature. With the engine running, observe the affected Long Term FT parameter with a scan tool. The reading should be between 0-19 percent.
⇒ If not within the specified range, inspect for the following:
• With the ignition ON and the engine OFF, observe the manifold absolute pressure (MAP) sensor parameter. The MAP sensor pressure should be within the range specified for your altitude. Refer to Altitude Versus Barometric Pressure.
⇒ Refer to DTC P0106 if the MAP sensor does not indicate the correct barometric pressure.
• With the engine idling, observe the mass air flow (MAF) sensor parameter. The MAF sensor parameter should be within 2-6 g/s at idle.
⇒ Refer to DTC P0101 or P1101 or DTC P0102 or P0103 if the MAF sensor parameter is not within 2-6 g/s at idle.
• Vacuum hoses for splits, kinks, and improper connections--Refer to Evaporative Emissions Hose Routing Diagram.
• Insufficient fuel in the tank
• Low fuel pressure--Refer to Fuel System Diagnosis.
• Fuel contamination--Refer to Alcohol/Contaminants-in-Fuel Diagnosis.
• Malfunctioning fuel injectors--Refer to Fuel Injector Diagnosis.
• Missing, loose, or leaking exhaust components from the HO2S forward--Refer to Symptoms - Engine Exhaust.
• Vacuum leaks at the intake manifold, the throttle body, and the injector O-rings
• The air induction system and the air intake ducts for leaks or for a missing air filter element
• A cracked EVAP canister
• Evaporative pipes obstructed or leaking
• The crankcase ventilation system for leaks--Refer to Crankcase Ventilation System Inspection/Diagnosis.
• The HO2S for improper installation and for electrical wires or connectors that may have contacted the exhaust system
• The HO2S signal circuit open, shorted to ground, or shorted to the low reference circuit
• Malfunctioning engine components--Refer to Symptoms - Engine Mechanical.
09-25-2016, 12:34 PM
#3
I originally brought that to them but they are thinking it's the vacuum from the not in use NPP exhaust now. I just don't see how it could be because it didn't start as soon as the NPP exhaust wasn't removed
09-25-2016, 01:18 PM
#4
Melting Slicks
Short answer: The p0171 code will not trigger as soon as the fuel mixture goes lean.
Longer answer: The ECM calculates a moving long-term average of fuel trim adjustments, as a healthy engine is constantly fluctuating within an acceptable range. Only after the short term adjustments fall outside the acceptable range for a long enough time will the code then trigger.
A vacuum leak can trigger that code. If you're sure the vacuum port is secured, clear the code. If it returns after a while, your problem lies elsewhere
Longer answer: The ECM calculates a moving long-term average of fuel trim adjustments, as a healthy engine is constantly fluctuating within an acceptable range. Only after the short term adjustments fall outside the acceptable range for a long enough time will the code then trigger.
A vacuum leak can trigger that code. If you're sure the vacuum port is secured, clear the code. If it returns after a while, your problem lies elsewhere
09-25-2016, 01:22 PM
#5
Short answer: The p0171 code will not trigger as soon as the fuel mixture goes lean.
Longer answer: The ECM calculates a moving long-term average of fuel trim adjustments, as a healthy engine is constantly fluctuating within an acceptable range. Only after the short term adjustments fall outside the acceptable range for a long enough time will the code then trigger.
A vacuum leak can trigger that code. If you're sure the vacuum port is secured, clear the code. If it returns after a while, your problem lies elsewhere
Longer answer: The ECM calculates a moving long-term average of fuel trim adjustments, as a healthy engine is constantly fluctuating within an acceptable range. Only after the short term adjustments fall outside the acceptable range for a long enough time will the code then trigger.
A vacuum leak can trigger that code. If you're sure the vacuum port is secured, clear the code. If it returns after a while, your problem lies elsewhere
09-25-2016, 04:19 PM
#6
NPP port is on the back of the intake manifold.
All you need to do is hit an auto parts store to pick up a vacuum line cap, pull the NPP hose off the port nipple and cap the port.
http://shop.advanceautoparts.com/p/d...FU9ffgodClELvg
This will solve the problem with the vacuum line open since the hose has been disconnected at the back of the car, and weed out if the problem is the open port line now.
All you need to do is hit an auto parts store to pick up a vacuum line cap, pull the NPP hose off the port nipple and cap the port.
http://shop.advanceautoparts.com/p/d...FU9ffgodClELvg
This will solve the problem with the vacuum line open since the hose has been disconnected at the back of the car, and weed out if the problem is the open port line now.
Last edited by Dano523; 09-25-2016 at 04:22 PM.
The following users liked this post:
Yaupon (09-26-2016)
09-26-2016, 01:01 AM
#7
NPP port is on the back of the intake manifold.
All you need to do is hit an auto parts store to pick up a vacuum line cap, pull the NPP hose off the port nipple and cap the port.
http://shop.advanceautoparts.com/p/d...FU9ffgodClELvg
This will solve the problem with the vacuum line open since the hose has been disconnected at the back of the car, and weed out if the problem is the open port line now.
All you need to do is hit an auto parts store to pick up a vacuum line cap, pull the NPP hose off the port nipple and cap the port.
http://shop.advanceautoparts.com/p/d...FU9ffgodClELvg
This will solve the problem with the vacuum line open since the hose has been disconnected at the back of the car, and weed out if the problem is the open port line now.
09-26-2016, 06:44 AM
#8
A vacuum leak will absolutely cause the P0171. Sounds like you have the problem identified. When they plug the leak, they'll have to do a code clear, otherwise you'll have to wait until the P0171 diagnostic runs and passes on 3 different key cycles before the check engine light will turn off (turns off on the 4th key cycle, after the diagnostic has passed on 3 previous key cycles).
The diagnostic doesn't pass immediately. You have to warm the car up and drive it for ~5-10 mins before it runs and reports a pass/fail. Quickest result would be to have them fix it and clear codes
The diagnostic doesn't pass immediately. You have to warm the car up and drive it for ~5-10 mins before it runs and reports a pass/fail. Quickest result would be to have them fix it and clear codes
Last edited by Kozzzz; 09-26-2016 at 06:46 AM.
09-26-2016, 11:29 PM
#9
Just need to block off the NPP nipple once you pull the hose off it, since the large port is the one that leads to the brake booster instead.
As for the brake booster line, double check the rubber fitting at the brake booster side, and if needed, a little dielectric grease does wonders to bring back a questionable fitting that may be slightly leaking.