03 Cobra Swap in GT Help. P0171, P0174

tropicmustang

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So I have a full 03-04 Cobra swap in my GT. Everything has been swapped including harnesses gauge cluster vacuum line etc. the car keeps throwing a P0171 and P0174. Car has been smoked and propane tested and no leaks are found anywhere. For safe measures the blower was polled and the intake gaskets were changed as well as the blower to manifold gasket. Mass airflow meter has been changed, All new O2 sensors. The car does have a ported blower on it but it is running a factory pulley. Does anyone have any ideas?
 

Roush6018

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I looked up the code, po171. Bank 1 detecting a lean condition. Bank 1 is passenger side. The info said either the fuel system is weak on that side, bank1, or a vacuum leak near the bank 1 Intake ports . This is causing a lean condition the computer can see and it turns on the SES light and sets the code.

I have an idea to check your fuel pressure. The fuel line supplies fuel on the passenger side of the engine. I have had a problem with my cobra fuel pumps, they split the factory fuel tubing inside the tank. This would cause low fuel pressure. I installed a PPRV delete.

use a scan tool to look at the bank 1 02 sensor and make sure it is reacting to the fuel being burned. This is the sensor the PCM is using In addition to the readings from the MAF to determine your car is running lean on bank 1.
 

hotcobra03

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On mine ,
Hose on bottom of intake for pcv,

This hose will harden. It will not pull off nipple ,but will spin. Which is a leak,

Ford did not use any clamp here.

Most common area for po 171/174 but also the most work to fix ,intake has to come off ,,
 

DSG2003Mach1

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On mine ,
Hose on bottom of intake for pcv,

This hose will harden. It will not pull off nipple ,but will spin. Which is a leak,

Ford did not use any clamp here.

Most common area for po 171/174 but also the most work to fix ,intake has to come off ,,

stupid Turkey pan hose causes the lightning guys a lot of hell too
 

tropicmustang

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stupid Turkey pan hose causes the lightning guys a lot of hell too

it was changed. Still having codes. Blower was pulled, new intake gasket blower gasket, egr new, lower tube under blower changed. My buddy is running out of options. I’m starting to think the ecu I bought second hand is a dud or corrupted somehow.
 

DSG2003Mach1

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it was changed. Still having codes. Blower was pulled, new intake gasket blower gasket, egr new, lower tube under blower changed. My buddy is running out of options. I’m starting to think the ecu I bought second hand is a dud or corrupted somehow.

a faulty ecu only throwing lean codes seems a little out there. Has the car been tuned for the mods? I mean maybe it's legit a tad lean if there isn't a vacuum leak.
 

tropicmustang

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a faulty ecu only throwing lean codes seems a little out there. Has the car been tuned for the mods? I mean maybe it's legit a tad lean if there isn't a vacuum leak.

long terms Pegging at 25 with short terms around 20.

Short terms are
a faulty ecu only throwing lean codes seems a little out there. Has the car been tuned for the mods? I mean maybe it's legit a tad lean if there isn't a vacuum leak.
 

SecondhandSnake

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Double check the PCV system for any leaks. Also check the exhaust side for leaks- manifold to midpipe or even where the oxygen sensor is installed.

On the other side what MAF and injectors are you using versus what are in the tune you're running? And does your mechanical measured fuel pressure agree with what the ECU is reporting?
 

hotcobra03

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Vacuum hose routing.

I had issues after ford replaced my head with codes ,,
I took it back after, got the run around and excuses on why its nothing they did .

I had posted a pic of engine in some thread on other issues and some one noted some hoses in wrong spot,,

Main line was connected after throttle body when it should have been before ,

If you haven't seen pdf on vacuum lines,

Google,

03 cobra vacuum hoses documented/svtperformance.com

Will bring you to thread with link
 

tropicmustang

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If everything checks out mechanically then it's a tune issue. Did you have the ECU reflashed or just throw it in and go?

So the blower is spinning stock boost levels but it’s ported. I have a JLT cold air intake but that’s it. The car is running on the base factory Ford tune.
 

tropicmustang

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If it had a ported blower, was there a tune done?

Running to bass factory for tune on it since it’s also running the stock size pulley on the car. Trying to get the swap legalized here in California so I have to have a stock pulley on it for inspection
 

tropicmustang

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Vacuum hose routing.

I had issues after ford replaced my head with codes ,,
I took it back after, got the run around and excuses on why its nothing they did .

I had posted a pic of engine in some thread on other issues and some one noted some hoses in wrong spot,,

Main line was connected after throttle body when it should have been before ,

If you haven't seen pdf on vacuum lines,

Google,

03 cobra vacuum hoses documented/svtperformance.com

Will bring you to thread with link

I’ll have my buddy double check all the line routing
 

tropicmustang

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Double check the PCV system for any leaks. Also check the exhaust side for leaks- manifold to midpipe or even where the oxygen sensor is installed.

On the other side what MAF and injectors are you using versus what are in the tune you're running? And does your mechanical measured fuel pressure agree with what the ECU is reporting?

The car has been smoke tested and propane’s. PCV system is pretty much new. Mid pipe was just off to change out all the O2’s. Now mani or midlife leaks.

The car is running stock injectors and a stock cobra mass airflow meter. The tune in the vehicle is the factory Ford tune it is not tuned. I am running stock boost levels. The only modifications on the car is the ported blower withthe stock pulley and the JLT intake
 

Black02GT

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JLT intake is the problem.

You need a stock inlet.

Is that one of the ones that you take the sensor out of the ring and put it in the tube? Increasing diameter and therefore scaling?

Wouldn't have thought of that. Good catch.
 

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