Interesting. Well now I know something new. Thanks.
03 Cobra Swap in GT Help. P0171, P0174
- Thread starter tropicmustang
- Start date
Interesting. Well now I know something new. Thanks.
It’s the JLT that uses the factory maf and housing. You thing that would also cause short terms and long terms to peg?
Bty,,
Is po171/174 the only codes showing.
Is po171/174 the only codes showing.
yes only codes showing. Only mods on the car is JLT and blower is ported with stock pulley. Not sure if the blower is the issue but I’m not spinning it faster… wouldn’t think that would cause a lean condition. Maybe I’ll talk with a tuner.
Decipha has already spoken lol
Seriously though - those cold air kits that use the stock maf and such can still cause all kinds of mayhem. The K&N FIPK kits for the Mach 1 guys would cause the car to stall if you put the clutch in while coasting among other things
SVT Documents
Link with our manuals..
Ford pinpoint test H. Fuel control
Is what you want,,
Has tests to follow for finding your issues,,
Leak isn't the only item on list,,
It also has test to do that data logging trims will change ,,and more.
The manual only works on a PC.
However Chilton library hosts this section and usable on cell.
I can't copy link from it,,or paste it ..format will change and no pictures post,,
Link with our manuals..
Ford pinpoint test H. Fuel control
Is what you want,,
Has tests to follow for finding your issues,,
Leak isn't the only item on list,,
It also has test to do that data logging trims will change ,,and more.
The manual only works on a PC.
However Chilton library hosts this section and usable on cell.
I can't copy link from it,,or paste it ..format will change and no pictures post,,
I have a terminator swap into my 2001 GT , with a stock pulley and a port on my supercharger, and running stock PCM with stock 03 cobra tune. and I got a bar label in my door jamb. I am trying to pass smog now and I have a code for a Evap leak. I am working on it. I used to be a Technician at a dealership but I just work on mine and family’s cars now.
your car is trying to get the bar label, so to me it sounds like you are going to need a stock intake tube with stock air box or K&N smog legal filter. I have a stock tube with a K&N filter with carb sticker.
However your car should run just perfect with that JLT and the port. You need to fix the root cause of the lean condition on the bank of the engine the code is saying.
You should be able to drive the car with a scanner connected and drive with the engine at 2500 RPM and look at the front O2 sensors. Verify the bank 1 sensor is reading a lean condition.
the computer could be thinking the MAF reading is not normal (broken) and make the fuel system run lean, but you should be able to get a NEW MAF and run it and the computer would see the reading from the new MAF in the JLT and adjust the fuel system to perfect or normal.
I just remembered when I did my swap the GT MAF had a screen on it and I put that screen on to my Cobra MAF, wasn’t running good, noticed the Cobra doesn’t need that screen and it ran so much better with that screen removed.
And fix the check engine light first, then get the BAR LABEL. I don’t think the JLT intake is the problem. Fuel pressure, intake vacuum leak, or MAF readings off.
The 03 cobra engine has MANY vacuum hoses that need to be checked out throughout.
your car is trying to get the bar label, so to me it sounds like you are going to need a stock intake tube with stock air box or K&N smog legal filter. I have a stock tube with a K&N filter with carb sticker.
However your car should run just perfect with that JLT and the port. You need to fix the root cause of the lean condition on the bank of the engine the code is saying.
You should be able to drive the car with a scanner connected and drive with the engine at 2500 RPM and look at the front O2 sensors. Verify the bank 1 sensor is reading a lean condition.
the computer could be thinking the MAF reading is not normal (broken) and make the fuel system run lean, but you should be able to get a NEW MAF and run it and the computer would see the reading from the new MAF in the JLT and adjust the fuel system to perfect or normal.
I just remembered when I did my swap the GT MAF had a screen on it and I put that screen on to my Cobra MAF, wasn’t running good, noticed the Cobra doesn’t need that screen and it ran so much better with that screen removed.
And fix the check engine light first, then get the BAR LABEL. I don’t think the JLT intake is the problem. Fuel pressure, intake vacuum leak, or MAF readings off.
The 03 cobra engine has MANY vacuum hoses that need to be checked out throughout.
Yeah we’ve swapped the mass airflow meter the car has all brand new O2 sensors on it. The JLT intake came with a carb sticker so the ref said that’s fine. The car has been smoke tested and found nothing but a leaky EGR valve that was replaced. Even to make sure we still pull the blower and replace the intake gaskets and the blower gasket. We are really leaning towards a corrupt file in the PCM. I’ve got a buddy with a spare PCM and we are going to try that out. Fuel system is checking out eve app is good. It seems like it’s one of those mystery codes that we’re trying to chase.
So got my car back from my friend after going through the system with no luck. I found that my DPFE hoses are reversed. Not sure that might be throwing the whole thing off and causing an EGR malfunction. If I post some data log information can someone help me out?
Stock inlet put back on with k&n style filter and still lean.
So it turns out the car has a GT dash harness….. hoping this might be causing the issues any ideas? Looks like whoever I bought the dash harness and the ECU harness from went to head and changed a pigtail so it would plug-in but I know there’s other differences in the dash harness from what I’ve read.
yes i have an idea on your problem. i think you can find the problem. the dash wire does not have anything to do with your check engine light.
i think your problem is fuel injector related. use a stethascope to listen to all 8 fuel injectors at idle, verify they are working by listening to them one by one. you should hear a tapping or knocking noise on each fuel injector.
if you find one that isn't working it will be making no noise at all. also i want to ask how is the car running and driving ? does it run great ? does it run bad ? does it stall out at a stop sign or stall when it is hot ? does this vehicle have an exhaust leak anywhere?
the computer is working ok because it is using the O2 sensors (and the MAF data ) to determine the lean condition in the exhaust gasses. , then set the codes (with freeze frame data ) and turn on the check engine light.
No stalling no drivability issues besides lean codes. I’m changing out harnesses either way. Injectors are all firing and the car isn’t missing. I’d rather have the peace of mind and eliminate a potential electrical issue by having all of the correct harnesses.
I would revisit the lower intake hose again ,and pcv hose and elbows ,,
It's the only area to throw both banks lean ,
Google
03 cobra vacuum hoses documented. Pdf2 has full vacuum harness detailed.
Routing of hoses maybe,
Clogged or restricted hose.
Vacuum harness is small and can be pulled completely to test in hand.
Except under intake hose
I'm not big on smoke test for this application,
Here is pin point test for 02 codes from manual just read all of them and foot notes .
There are test to do to see if pcm is actually working which it most likely is ..
It's the only area to throw both banks lean ,
03 cobra vacuum hoses documented. Pdf2 has full vacuum harness detailed.
Routing of hoses maybe,
Clogged or restricted hose.
Vacuum harness is small and can be pulled completely to test in hand.
Except under intake hose
I'm not big on smoke test for this application,
Here is pin point test for 02 codes from manual just read all of them and foot notes .
There are test to do to see if pcm is actually working which it most likely is ..
Fuel trims pegged at idle but what about elevated rpm? If they're normal at 2k it's almost always a vacuum leak. Smoke the entire intake from maf to heads or just part of it? No breathers or catch cans? Vacuum line to boost gauge intact or capped?
Ltft go to 1.0 at 2k rpms
Stft go to .75
I’m just lost because everything was gone through and smoke tested. Everything is stock Evap, pcv.
Hey I have a cobra swap in my mustang GT. I did the swap myself and I got it smog check at the referee. I can help you diagnose your car. Then we can report back to this thread and identify the problem you had so other people can learn about this mustang swap.
Do you want me to check my STFT and LTFT so you can compare? At idle and at 2k rpm ?
I can also check the same voltage readings on my car (known good) to the voltage readings on your car. (O2 sensor voltages)
We can even swap my PCM into your car and we can call the locksmith to get it to run in your car. To see if my PCM will throw the lean codes when installed in your car. My ECM is good and all my monitors will run and then complete.
Do you want me to check my STFT and LTFT so you can compare? At idle and at 2k rpm ?
I can also check the same voltage readings on my car (known good) to the voltage readings on your car. (O2 sensor voltages)
We can even swap my PCM into your car and we can call the locksmith to get it to run in your car. To see if my PCM will throw the lean codes when installed in your car. My ECM is good and all my monitors will run and then complete.
The reason I say lower intake hose to revisit,,
The original hose will harden,
It will not pull off nipple,but will spin on nippple when moved,
Ford did not use a clamp ,,
It's so hidden it makes a smoke test impossible,,
All the other lines are in your face. ..
I found out when I did this game,just a clamp on mine and codes were gone.
I'm sure your o2s are telling you this in your datalog .
The original hose will harden,
It will not pull off nipple,but will spin on nippple when moved,
Ford did not use a clamp ,,
It's so hidden it makes a smoke test impossible,,
All the other lines are in your face. ..
I found out when I did this game,just a clamp on mine and codes were gone.
I'm sure your o2s are telling you this in your datalog .
i agree the lower hose is a common area to cause the code to set for both banks. the 02 sensors are seeing this lean problem. i am going to datalog my front o2 sensors while driving at 2k rpm this weekend so OP has something to compare.
That is nearly always a vacuum leak. I'm also leaning towards pcv under the intake. Monitor stft and o2s11/o2s21 at idle while spraying brake clean under the intake. You should see fuel trims climb and o2s respond.
Even a missing oil cap or dipstick can cause it.
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