2019 Mustang GT

[brentonm74]

Hey guys. I have a bricked 2019 Mustang.This all started in March and the car has been at the dealership ever since.

So it all began with a random misfire code. It's started in cylinder 3, then there were codes for multiple cylinder misfire. I was cruising on the highway and passing a vehicle the car started sputtering and the check engine light began blinking and then went out. The issue resolvedm. I got home and parked it. The next morning, I went out to started it so the tow truck could take it to the shop and had was streaming from the right side tailpipe.

1st diagnosis was the car needed a new motor after being bore scoped there was a claim of damage to cylinder 3. I had a second opinion done and then Ford said there was no damage.

So here is the list of fixes so far and still there is a misfire detected.

3 Fuel injectors for cylinder 3, 5, and 8
4 o2 sensors, all we're replaced
New spark plugs
New intake manifold since it was determined the IMRC might have been bad.
New PCM unit

Nothing has worked so far. Ford has no idea what could be causing this issue. I told them from the start there is something electrical going on but they haven't figured it out yet. It's been frustrating not having my car.

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[shogun32]

started it so the tow truck could take it to the shop and had was streaming from the right side tailpipe.

you mean 'gas' was streaming I assume? Sounds like engine+harness replacement time. That much gas flowing around washes oil off the cylinders, dilutes the oil which leads to scoring, bearing damage and all kinds of other things. Otherwise break out the oscilloscope and confirm the injector pulse is being signaled correctly and the injector is behaving to match.

If I had to guess it's the Port Injector(s) getting bad signal (the voltage doesn't drop low enough to turn OFF) and so they dribble fuel into the intake constantly - caused by a short or bad ground. Below a certain RPM the engine uses just DI. I think you can yank the PI set and drape them over the engine and run the RPM up to where they are supposed to turn on and see them in action. Have a fire bottle handy!

 

[brentonm74]

you mean 'gas' was streaming I assume? Sounds like engine+harness replacement time. That much gas flowing around washes oil off the cylinders, dilutes the oil which leads to scoring, bearing damage and all kinds of other things. Otherwise break out the oscilloscope and confirm the injector pulse is being signaled correctly and the injector is behaving to match.

If I had to guess it's the Port Injector(s) getting bad signal (the voltage doesn't drop low enough to turn OFF) and so they dribble fuel in the intake constantly. A short or bad ground.

When I say streaming on the initial start, it kept cranking and it flooded but it was only on the right side. I got the car back after the initial repair. The dealership replaced injectors (2) and all the spark plugs and concluded it was fixed. I drove it 1 day and the issues were still present so I dropped it back off. Fords top engineers have been studying my car and they haven't nailed it down yet. The engine was damaged was the first thing they suspected but my car is new with 15k miles so after 2 investigations they took that off the list. I suspect an electrical issue.

 

[brentonm74]

When I say streaming on the initial start, it kept cranking and it flooded but it was only on the right side. I got the car back after the initial repair. The dealership replaced injectors (2) and all the spark plugs and concluded it was fixed. I drove it 1 day and the issues were still present so I dropped it back off. Fords top engineers have been studying my car and they haven't nailed it down yet. The engine was damaged was the first thing they suspected but my car is new with 15k miles so after 2 investigations they took that off the list. I suspect an electrical issue.

Also. They did check oil but no fuel was in the oil, it went through the manifold and out the pipe. All the issues seem to be on the right side. Only upgrades to my car is the CAI.

 

[shogun32]

Fords top engineers have been studying my car and they haven't nailed it down yet.

if they haven't confirmed correct signal to each injector at the various states, then they are play-acting. Did they put the car on a dyno and check? Or did they bring a PCM simulator that fooled it into thinking an engine was running and check the injector signals?

If the engine harness is sufficiently modular they may be able to replace just half of it.

 

[brentonm74]

if they haven't confirmed correct signal to each injector at the various states, then they are play-acting. Did they put the car on a dyno and check? Or did they bring a PCM simulator that fooled it into thinking an engine was running and check the injector signals?

If the engine harness is sufficiently modular they may be able to replace just half of it.

So when I was out there yesterday, they replaced the PCM with a brand new PCM.it was programmed for my car. I had to bring my spare key. As far as a dyno, no they just have it in the shop stale.

 

[shogun32]

As far as a dyno, no they just have it in the shop stale.

no oscilloscope, no diagnosis. sounds like they need to go back to Diagnostics School.

 

[brentonm74]

no oscilloscope, no diagnosis. sounds like they need to go back to Diagnostics School.

Same thing I said. I have worked on S550 program since 2014 and I have never seen techs and fellow engineers misdiagnose this many times. I offered them advice on what it could be, something electrical since day one. They keep trying other stuff and haven't found it yet so I don't know when ill get my car back. I feel like getting it out and taking it to another dealership

 

[shogun32]

If Lemon law applies you can pull out that hammer. And/or get a CSR involved.

 

[brentonm74]

I'm going to see what todays diagnose is and plan my next steps. Mach 1 might be in my future

 

[brentonm74]

I'm going to see what todays diagnose is and plan my next steps. Mach 1 might be in my future

Found out the issue.my CAI was throwing off the air/fuel ratio.

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