GT Stall Prevention?

[hiccup]

Well sorry mlc stang but this non feature works on a hill too with my PP Gt. As I release brake on a hill and just begin to roll back I come off the clutch a hair and the rpms still rise to get me moving before I have to give it gas. Now if I come off the clutch fast enough it will stall. For some reason this auto throttle is there and its cool to have on my performance pack Gt

Sponsored

 

[ManBearPig]

MLC Stang is right, it isn't any specific feature, the car just has a computer set min RPM, it tries to maintain that RPM. When you let the clutch out it simply opens the throttle a tad to keep its idle RPM.

So, while it isn't a direct feature it works as anti stall.

This makes sense. The PCM probably just doesn't like to see RPM below a set value so if it is able to make minor throttle inputs to keep idle steady it does seem to. Again, I feel certain that if you really drive poorly the car would stall, But I don't want to find out bad enough to try.

 

[JohnD]

Well sorry mlc stang but this non feature works on a hill too with my PP Gt. As I release brake on a hill and just begin to roll back I come off the clutch a hair and the rpms still rise to get me moving before I have to give it gas. Now if I come off the clutch fast enough it will stall. For some reason this auto throttle is there and its cool to have on my performance pack Gt

But it's also got the hill start assist thing built into it, unless you disabled it. Personally, I could do without all this wizardry just fine. I learned to drive at age 16 on a 1964 Plymouth Valiant with a 273 V8 and a 4 speed with Hurst shifter, posi rear end and buckets. It was my Mom's car! Driving a manual is kinda second nature, even at my senior citizen age.

 

[jasonstang]

All fuel injection engines with electronic throttle body would try to maintain the normal idle speed by adding more throttle opening electronically so yes when you let off the clutch slowly and the rpm starts to drop, the engine sees a load and would open up the throttle body to maintain the normal idle speed.
Of course you can still stall it by letting out the clutch too fast. Nothing new this feature has been in all cars for the last 10 - 15 years since the introduction of electronic throttle body.

 

[Boosted5.0_NY]

All fuel injection engines with electronic throttle body would try to maintain the normal idle speed by adding more throttle opening electronically so yes when you let off the clutch slowly and the rpm starts to drop, the engine sees a load and would open up the throttle body to maintain the normal idle speed.
Of course you can still stall it by letting out the clutch too fast. Nothing new this feature has been in all cars for the last 10 - 15 years since the introduction of electronic throttle body.

And that is what I've been saying. It's not a feature, just normal design in all manual cars for a number of years now.

 

[TheReaper]

I noticed by accident that these (GT if it matters) cars seem to have some sort of computer wizardry that prevents the car from stalling. Once I discovered this I noticed that you can engage the clutch without any throttle and even with the parking brake on, the RPM will only drop so far, and then actually rises back up even if the clutch is engaged even further. Now I don't like to make a habit of just burning up a clutch needlessly so I didn't experiment much but now I'm curious. First...is this normal for these cars? And second...how is it achieved? Considering the throttle is computer controlled, does the pcm just signal to feed more throttle when it detects the RPM dropping below X value? Lastly....can this be disabled? I've got the hill assist turned off, wondering if this is something that can be disabled, too?
Thanks

My 2007 GT would do this, never tried with the brake on.

 

[hiccup]

No hill assist enabled on my Gt. Been driving a stick off and on for 40 years of my life. Good info guys!

 

[MadCow]

What you people are describing sounds more clutch related than computer. Maybe the car has a mechanism to keep the clutch from fully engaging in certain instances. Cause if the driveline is gonna stall the engine theres nothing the computer can do about it. It could try to raise the RPM, but somethings got to give. Either the clutch will slip, the brakes will slip, the driveline will break, or the engine will stall.

 

[hiccup]

No its not a slipping clutch. What we are saying here is that its not required to press the gas pedal to get rolling from a dead stop. What we do is let out the clutch just a hair and push it back down. The engine computer senses the slight load and raises the rpm. As its doing this we let out on the clutch as we normally do and off we roll then press the gas and go! ..and I thought all this time it was just something that my Gt did lol.

 

[OSBRanger]

I'm driving an auto and looking to go stick within the next couple years. I wanted to clarify something; When you're in N and you engage the clutch and shift into 1st, can you let off the clutch easliy, without the brakes and without your foot on the gas, and make the car move forward by itself. It seems from what you guys are saying this can be done.

 

[soldier989]

I'm driving an auto and looking to go stick within the next couple years. I wanted to clarify something; When you're in N and you engage the clutch and shift into 1st, can you let off the clutch easliy, without the brakes and without your foot on the gas, and make the car move forward by itself. It seems from what you guys are saying this can be done.

Yes, this is what they're describing. I'd have to say that this is one of the easiest manuals I've ever driven (probably driven about 30). You can still stall them, but the car does a good job helping prevent that.

 

[Keith_PDX]

And that is what I've been saying. It's not a feature, just normal design in all manual cars for a number of years now.

Matt Farah talks about this in his first episode of How to Drive a Manual. It's something Ford does to help prevent stalls. I noticed it on my test drive. It's definitely more pronounced than just standard FI trying to maintain idle. If you watch Episode 1.5, he specifically changes cars to a Mazda 2 just to demonstrate the difference.


FYI, if you're trying to teach someone new to manuals how to drive, I highly recommend having them watch all three videos a few times before their first practice behind the wheels. Worked wonders in my case teaching a new driver.

Cheers
Keith

 

[MadCow]

No its not a slipping clutch. What we are saying here is that its not required to press the gas pedal to get rolling from a dead stop. What we do is let out the clutch just a hair and push it back down. The engine computer senses the slight load and raises the rpm. As its doing this we let out on the clutch as we normally do and off we roll then press the gas and go! ..and I thought all this time it was just something that my Gt did lol.

Here are some quotes

Once I discovered this I noticed that you can engage the clutch without any throttle and even with the parking brake on, the RPM will only drop so far, and then actually rises back up...

if you can place the car in gear, with the emergency brake engaged, and release the clutch without stalling - you probably have a problem with your clutch.

The original post and a few others are talking about letting the clutch out with the car in gear and the parking brake on. That doesn't seem to indicate the OP was referring to the car moving and I am not the only person who read it this way. But to the point. If you are referring to the ability to slowly release the clutch at idle and move the car, this isn't a feature. Its literally how every manual trans ever has worked. Even ones with carbs and no computer. ICEs have to idle and they are making power at idle even if it's only a little. If the power at idle is enough to move the load of the vehicle it simply won't stall. This is why your transmission has gears.

 

[Norm Peterson]

Yes it's that way on purpose. It will only happen from a stop. The PCM will detect an increase in load at low or no throttle from a stop and open the throttle a little to allow you to launch.

Not just from a stop, though that's probably when it's most noticeable.

"Stall-saver" routines have been incorporated into EFI systems since the days of idle air motors on much simpler speed-density systems. Even on aftermarket S-D systems.

Nominally, the reason is to keep large suddenly applied load demands on the engine from stalling the engine when at a full stop. Such as from shifting an AT into gear, A/C cycling or adding to the alternator demand (rear window defogger, seat heaters, headlights, etc.).


Norm

 

[Norm Peterson]

I'm driving an auto and looking to go stick within the next couple years. I wanted to clarify something; When you're in N and you engage the clutch and shift into 1st, can you let off the clutch easliy, without the brakes and without your foot on the gas, and make the car move forward by itself. It seems from what you guys are saying this can be done.

Entirely possible . . . and pretty easy once you've gotten accustomed to where the clutch begins to grab and have developed a feel for how fast you can feed the rest of the engagement in.


Norm

Sponsored