07 Mustang GT no idle or gas pedal.

[rotorydial777]

New to me 07 Mustang GT. The car runs and drives with MAF unplugged. I have troubleshoot and replaced the following: repaired MAF harness (broken wire), new throttle body replaced with oem 55mm unit, pvc hoses and EVAP valve replaced, new bank 1 O2 sensors, coils, spark plugs and remanufactured PCM and still cannot track down the problem. I have tested all the pins and cannot locate and shorts. I get a closed loop fault fuel error on live data. Please point me in the right direction.

 

[teeje]

New to me 07 Mustang GT. The car runs and drives with MAF unplugged. I have troubleshoot and replaced the following: repaired MAF harness (broken wire), new throttle body replaced with oem 55mm unit, pvc hoses and EVAP valve replaced, new bank 1 O2 sensors, coils, spark plugs and remanufactured PCM and still cannot track down the problem. I have tested all the pins and cannot locate and shorts. I get a closed loop fault fuel error on live data. Please point me in the right direction.

I mean this sounds crazy, but have you replaced the maf sensor? Post wasn't very clear on this if you have or not.

Sent from my SM-G998U using Tapatalk

 

[rotorydial777]

Yes, MAF has been replaced.

 

[Jack F]

I have tested all the pins and cannot locate and shorts. I get a closed loop fault fuel error on live data.

Might want to translate this from gibberish into English. DTCs would help you as well.

 

[rotorydial777]

P2197 with a closed loop fuel system error. The pcm is new and the harness has been tested from pin to O2 sensors, MAF, throttle body. O2 sensors, MAF, throttle body have all been replaced. Still undrivable without unplugging the maf. Any support or suggestions will be helpful.

 

[teeje]

I know you're trying your best there but we need some.more info. What does it do when it's plugged in? How does it run when plugged in? What pcm did you replace it with? What year? What year is yours? Was the pcm it came from manual or auto? Is yours auto or manual? Check the SJB make sure its clean,

Check the harness for the o2 sensors
Check fuel pressure
Check the FRPS, see if it is leaking or bad
A simple test would be to take the vacuum line off of the frps and see if you smell gas. If you do, the diaphragm inside is bad and the sensor needs replaced. Some slight vapor smell is OK.

The harness going to to o2 sensors is very sensitive. If you get any shorts or anything or a bad connection, it will cause issues.
Sent from my SM-G998U using Tapatalk

 

[rotorydial777]

The car will start and staff with the maf plugged in. The maf harness had a break which has been repaired. The PCM is an exact clone of my original from Flagship 1. If I attempt to drive with the maf plugged in I will almost immediately stall or go into rough idle with no throttle response. I am not getting DTC's when attempting to drive and I go into stall/safe mode. I can restart the car after a stall and limp off the street in order to unplug the maf. I replaced both O2 sensors and checked continuity through the harness and didn't find any problems. I downloaded the shop manual and started going through possible solutions. I am thinking it has to be something relatively simple but can be a number things. If was not sure if there is a weak point that the group would say start here because it's a common issue. Thanks again

 

[rotorydial777]

I will check your recommendations. It's an 07 GT w/automatic.

 

[teeje]

No common issue that I can think of. The only common issues I can think of that entail wiring is the SJB getting water in it, and the fpdm in the trunk getting water in it.

Sent from my SM-G998U using Tapatalk

 

[rotorydial777]

Teeje,
The fpdm visibly displays signs of water intrusion. I haven't had an opportunity to test but is next on my list. Fuel pressure is reading anywhere between 39-51psi during rough idle per live data from my scanner which should rule out the frps. I also changed the fuel filter when I recently changed the plugs and coils. Thanks for the support.

 

[BAD3VLV]

Have you visually checked to see if the throttle blades are opening like they are supposed to? Did you do an idle relearn after installing new throttle body?

 

[07gts197]

These are the exact symptoms my old 02 Gt had when the maf and filter came off in the fenderwell. It would idle but as soon as I’d hit the gas it would stall because the increase in airflow wasn’t detected from the maf.


Sent from my iPhone using Tapatalk

 

[Juice]

These are the exact symptoms my old 02 Gt had when the maf and filter came off in the fenderwell. It would idle but as soon as I’d hit the gas it would stall because the increase in airflow wasn’t detected from the maf.


Sent from my iPhone using Tapatalk

Agreed, sounds like a huge vacuum leak between the maf and throttle body.
When the MAF is unplugged, it forces the pcm to run off the SD (speed density) map (failed MAF) Live data should show this as a super lean condition (w/maf plugged in) and adaptive adding a ton of correction.

So, can you confirm live data STFTs while idling with maf plugged in?

 

[Juice]

Dumb question: the MAF sensor is not in backward by chance?

 

[DiMora]

Teeje,
The fpdm visibly displays signs of water intrusion. I haven't had an opportunity to test but is next on my list. Fuel pressure is reading anywhere between 39-51psi during rough idle per live data from my scanner which should rule out the frps. I also changed the fuel filter when I recently changed the plugs and coils. Thanks for the support.

The fuel rail pressure needs to be exactly 39. I would replace the FRPS....it should NOT be fluctuating at all.

The ECU uses Pulse Width Modulation to "pulse" the fuel pump top keep the pressure at 39.

The FRPS tells the pump to pulse faster or slower as needed (fuel pump duty cycle) to keep that 39. If you are seeing fuel rail pressure outside of that 39 target (I would say 38-40 should be about all the fluctuation you will see) then either your FRPS, fuel pump driver module from the trunk (FPDM), or the fuel pump itself is shot. Also replace the fuel filter which is under the car on the driver side pretty much under the driver's side door area.

Thread from when my FRPS died:

https://www.s197forum.com/threads/stang-ran-rough-then-died-and-would-not-start-edit-solved.133995/

 

[Damanikc94]

Hey I'm sorry for jumping on the thread so late, but I just bought an 05 GT and I'm having the same issue as you, rotorydial777. Did you ever find the problem? I'm literally losing my mind on this.