Pronounced Driving Mode Differences?

[pilotgore]

When the car is off and you push the clutch in as if to start it (but without actually hitting the start button) do you hear a mechanical actuating sound coming from underneath the car? The exhaust valves cycle that way each time. That will tell you if the exhaust valves themselves are not working or if it is some kind of communication issue between the mode selector and the valves.

As far as differences in suspension and steering settings on normal vs sport, there should be a noticeable difference in steering stiffness and a more nuanced increase in suspension stiffness. I can notice it on certain bumps along roads that I normally take to and from work.

+1 on hearing the valves cycling at startup. If you don’t hear cycling, did you confirm the harness is actually plugged into the flapper valve motors? Less likely, but it’s possible the last owner had a defeat device plugged in for keeping the car quiet on track (certain tracks have DB limits.)

On the suspension front, I can’t really tell a difference on the street. All of my cars have stiff suspension, so maybe that’s desensitized me to the mode changes on the mustang. The stiffness settings only really became apparently to me at track attack while doing the slalom circuit and changing between modes. The difference in body role and steering feel became very apparent.

As to your question about the position of the valves, my car’s in storage for the winter so I can’t say for sure. To the best of my memory though, when the valves are closed, they appear fully or 90% closed. When open, they appeared fully open.

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[BierGut]

There is nothing about this problem that sounds like a stock GT350. As @galaxy said, there's an error message on the dash if the valves aren't moving and your ability to switch drive modes is disabled. Your car doesn't do that. Not only that, but the shocks should change settings too, and the car should get a stiffer ride in Sport and even stiffer in Track. The dashboard is saying the right things, but the car isn't actually responding. Very strange, and very hard to do.

At this point, you need to find out what's going on. So, first, go to this Ford website: https://www.etis.ford.com/vehicleSelection.do and enter your VIN. It'll tell you exactly what the car was built as. Once we're sure you've actually got a GT350, we can start to figure out what's going on from there. There are products in the aftermarket that will disable both the MagneRide suspension and the exhaust sound valves. Could be your car has them for some reason.

What type of aftermarket products might do this? Are you suggesting tuning mods?

 

[pilotgore]

What type of aftermarket products might do this? Are you suggesting tuning mods?

This is one of the devices some owners use to keep the valves closed, and the system fooled into thinking its operating normally: https://www.grimmspeed.com/exhaust-...MI7c2Yubnf7gIVSr3ACh2rTw-EEAQYASABEgJVA_D_BwE

 

[sox3]

This is one of the devices some owners use to keep the valves closed, and the system fooled into thinking its operating normally: https://www.grimmspeed.com/exhaust-...MI7c2Yubnf7gIVSr3ACh2rTw-EEAQYASABEgJVA_D_BwE

Installed tge grimmspeed on my friends R to keep valves open all the time. Can be used to keep them shut as well if wanted. No fault message will show on dash.

 

[BierGut]

+1 on hearing the valves cycling at startup. If you don’t hear cycling, did you confirm the harness is actually plugged into the flapper valve motors? Less likely, but it’s possible the last owner had a defeat device plugged in for keeping the car quiet on track (certain tracks have DB limits.)

On the suspension front, I can’t really tell a difference on the street. All of my cars have stiff suspension, so maybe that’s desensitized me to the mode changes on the mustang. The stiffness settings only really became apparently to me at track attack while doing the slalom circuit and changing between modes. The difference in body role and steering feel became very apparent.

As to your question about the position of the valves, my car’s in storage for the winter so I can’t say for sure. To the best of my memory though, when the valves are closed, they appear fully or 90% closed. When open, they appeared fully open.

Okay -- when the clutch is depressed before ignition, the valves DO cycle. (But the switch has no effect on sound once started)

The driving modes while idling can be called up EXCEPT for drag. I get a message in the drag mode saying it is not available.

If I had to guess -- I believe the exhaust valve SETTING is open as it's fairly loud and raspy, but I've verified the valves are ONLY OPEN about 5-7 millimeters. I can move them with a screwdriver. They move somewhat freely, but with some force and snap back into their static position once pressure is released.

Given it's winter, roads are covered in snow and salt I cannot test the suspension while driving. In a few hours at lunch I will try the "push down" test. I'll change modes and see if the car feels any different while I push down or hop on the threshold. This should tell me if the dampers are going from one stiffness to another. (I predict they are not) Like I previously mentioned, I couldn't tell a difference in stiffness while driving between all the modes. I would also not consider the damping as stiff. Coming from a 2015 Z/28, the GT350 felt much softer.

At any rate -- certainly sounds like this puppy has to go back to the dealer for some diagnosis. But I do want to hear thoughts and opinions, as I am not how certain I can rely on dealer for expert work.

 

[BierGut]

This is one of the devices some owners use to keep the valves closed, and the system fooled into thinking its operating normally: https://www.grimmspeed.com/exhaust-...MI7c2Yubnf7gIVSr3ACh2rTw-EEAQYASABEgJVA_D_BwE

Thank you for this. Once of the first questions I had for the salesman at the dealer was please ask the previous owner whether he installed something like this. Of course, I've not heard back. I will continue to press the issue.

If indeed my new to me GT350 has something like this installed and the car was loud all the time, I would not have an issue with it -- but I would like to know.

 

[pilotgore]

Okay -- when the clutch is depressed before ignition, the valves DO cycle. (But the switch has no effect on sound once started)

The driving modes while idling can be called up EXCEPT for drag. I get a message in the drag mode saying it is not available.

If I had to guess -- I believe the exhaust valve SETTING is open as it's fairly loud and raspy, but I've verified the valves are ONLY OPEN about 5-7 millimeters. I can move them with a screwdriver. They move somewhat freely, but with some force and snap back into their static position once pressure is released.

Given it's winter, roads are covered in snow and salt I cannot test the suspension while driving. In a few hours at lunch I will try the "push down" test. I'll change modes and see if the car feels any different while I push down or hop on the threshold. This should tell me if the dampers are going from one stiffness to another. (I predict they are not) Like I previously mentioned, I couldn't tell a difference in stiffness while driving between all the modes. I would also not consider the damping as stiff. Coming from a 2015 Z/28, the GT350 felt much softer.

At any rate -- certainly sounds like this puppy has to go back to the dealer for some diagnosis. But I do want to hear thoughts and opinions, as I am not how certain I can rely on dealer for expert work.

Thank you for this. Once of the first questions I had for the salesman at the dealer was please ask the previous owner whether he installed something like this. Of course, I've not heard back. I will continue to press the issue.

If indeed my new to me GT350 has something like this installed and the car was loud all the time, I would not have an issue with it -- but I would like to know.

If one of these is installed, you’d be able to tell very quickly, as it plugs into the connector meant for the flapper motor. If the flapper motor/actuator has wires plugged into it, I’d say it’s a safe bet the grimspeed model is not installed.

You may want to consider setting up a camera looking into the exhaust pipe to video the valves in motion when the clutch is pressed prior to startup. I’m not sure of your mechanical background but it’s entirely possible you’re hearing the electric fuel pump Pre-pressurizing the system and mistaking that for the valves moving.

The valves should also open at wide open throttle.

Very odd about the mode selection and this problem in general. It may be worth having a Ford dealer look into it and possibly flash the pcm to the most current software. I doubt the cost would be excessive for a diagnostic (but I’ve been wrong before.)

Best of luck!

 

[BierGut]

You may want to consider setting up a camera looking into the exhaust pipe to video the valves in motion when the clutch is pressed prior to startup. I’m not sure of your mechanical background but it’s entirely possible you’re hearing the electric fuel pump Pre-pressurizing the system and mistaking that for the valves moving.

Ah yes! You might very well be spot on here, now that you mention it. My experience is all as just being a owner... I can do a break job, but not much else. I certainly have zero working knowledge of a modern cars electrical workings. I'll have my better half depress the clutch as I watch the valves. Good advice.

 

[pilotgore]

Ah yes! You might very well be spot on here, now that you mention it. My experience is all as just being a owner... I can do a break job, but not much else. I certainly have zero working knowledge of a modern cars electrical workings. I'll have my better half depress the clutch as I watch the valves. Good advice.

Keep us posted.

You may need to lock the car with the key fob, then unlock, then depress the clutch. After the valves cycle once during the Pre-start test, I think the car needs to think you’re done driving it (by closing door and locking it), before it’ll run the test again.

Like I said earlier, I’m operating off memory and may be completely wrong.

 

[Postal Bob]

from a purely sound perspective, quiet to normal is a huge difference,
normal to sport I can kind of tell the difference,
sport to track I cannot tell one bit

This is for a GT car, not a GT350. GT350's only have normal, and loud(sport) exhaust settings. Quiet mode?

 

[Point45]

This is for a GT car, not a GT350. GT350's only have normal, and loud(sport) exhaust settings. Quiet mode?

This, you should not need to go through all this trouble to see if the exhaust valves are working.

There is a significant difference in noise and there are only two modes, quiet and loud. Anything not in normal driving mode will set the exhaust to loud unless you override it with the exhaust switch.

If you can't tell when revving the engine then the valves are not working.

 

[BierGut]

This, you should not need to go through all this trouble to see if the exhaust valves are working.

There is a significant difference in noise and there are only two modes, quiet and loud. Anything not in normal driving mode will set the exhaust to loud unless you override it with the exhaust switch.

If you can't tell when revving the engine then the valves are not working.

Presumptive comment ... If one has never heard the different GT350 settings, one wouldn't necessarily know. The car is loud and raspy, is it the loud mode? How would I know? This is my very first experience with a GT350.

If it was a Z/28 or Porsche with their sport exhaust I would have some experience.

So again -- I'm working on determining whether they are open or closed. I'll know later with luck.

 

[BierGut]

Alright -- The valves are open "part way". The left bank is open 5-7mm and the right bank valve is open more than that, looks like 10-12mm.

They do not move when the clutch is depressed. They do not move when any drive mode is changed. They are not "stuck" as I can move them with a screwdriver -- they just don't actuate at any time, but remain partly open.

???

 

[pilotgore]

Alright -- The valves are open "part way". The left bank is open 5-7mm and the right bank valve is open more than that, looks like 10-12mm.

They do not move when the clutch is depressed. They do not move when any drive mode is changed. They are not "stuck" as I can move them with a screwdriver -- they just don't actuate at any time, but remain partly open.

???

Sounds like a Ford dealer is in your future.

 

[JAJ]

Alright -- The valves are open "part way". The left bank is open 5-7mm and the right bank valve is open more than that, looks like 10-12mm.

They do not move when the clutch is depressed. They do not move when any drive mode is changed. They are not "stuck" as I can move them with a screwdriver -- they just don't actuate at any time, but remain partly open.

???

Then you must have the Grimmspeed eliminators or something like it installed. The GT350 ECU considers the muffler valves an integral part of the engine airflow management system and it gets pretty grumpy when the valves aren't working. So, if your car is working okay but the valves aren't moving with the switch or the start-up sequence, then something is convincing the ECU that all's well. That's what the eliminators do. They're for people who want the valves stuck open or closed all the time.

Someone with a GT can correct me, but AFAIK, the Mustang GT muffler valves are decorative and the ECU might not care whether they're working or not. But the GT350 ECU will throw a code and it might even go to limp mode - that I'm not sure of.

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