Throttle lag for engine braking

dawater · Jul 28, 2007

Anyone ever noticed that when you are going down a hill, and you gear it down, the throttle is on some kind of "cruise control" for 3-4 seconds before you actually get to start using engine braking? Any hand held tuners that will help this? How about the more advanced laptop tuners like the Sniper or similar? I have the cheap SCT tuner, and it didn't do anything for it. It did help the throttle response on acceleration. Not sure if the 96-04 Mustangs did this or not, since this is my first Mustang.

shooterm1 · Jul 28, 2007

You drive an Automatic obviously .....

red05bullitgt · Jul 28, 2007

dawater said:
Anyone ever noticed that when you are going down a hill, and you gear it down, the throttle is on some kind of "cruise control" for 3-4 seconds before you actually get to start using engine braking? Any hand held tuners that will help this? How about the more advanced laptop tuners like the Sniper or similar? I have the cheap SCT tuner, and it didn't do anything for it. It did help the throttle response on acceleration. Not sure if the 96-04 Mustangs did this or not, since this is my first Mustang.

The reason for you're throttle lag ! is because you more than likely, own the preloaded 9415 SCT canned tuner ? If you either upgrade to Bamachip's or Brenspeed's, mail order custom tunes ? I guarantee, you'll no longer have any throttle lag issues..However, before your able to upload an LL3 custom tune file, into the programmer ? you'll also be required to re-format your 9415 tuner, from a preloaded tuner.. into a standard 9400 custom tuner, in which you'll also need to go into the SCT website, and then download their live load 3 software, prior to re-formatting your device ! I would also recommend, that you contact SCT tech support and have them walk you through, each step during the re-formatting process as well..Anyway, best of luck to you..

dawater · Jul 28, 2007

shooterm1 said:
You drive an Automatic obviously .....

No, its a 5 speed manual... It just seems to take a while before the electronic throttle drops back down when you let off, when engine braking. I want the throttle to close exactly when I let off the gas. It feels like its on cruise control for 3 seconds or so, even when revved up to 3k or more.

It may because of the canned tune. I got it from rpmoutlet.com (a mistake, don't ever buy from them. They (to their own admission) owe me money, but wont respond to my emails and you can't call them for customer service). I may have to try Bamachips or Brenspeed, but I'm sure it won't be cheap.

I wish I knew for sure that it would fix it.

red05bullitgt · Jul 29, 2007

Dawater. I already pointed all that out, in my previous reply ! Therefore, I recommend that you read it over, again..

dawater · Jul 29, 2007

Yeah, I read it. I was mostly agreeing with you in the start of my second paragraph. But, your post wasn't specific enough for me to be sure that it will fix it. I did email Brenspeed about it--thanks for the suggestion. When most people talk about the throttle lag on these cars, its on acceleration, not deceleration. My lag on acceleration is gone with the tune, and I hate to spend more $$ without being 100% sure.

I'd like to know if the sniper (or other laptop tuning software) will give you control over this decel throttle lag. I'm not sure that I want to do another canned (or custom email order) tune. I come from the do-it-yourself HPTuners world of GM V8's where you have complete control over hundreds of parameters.

I guess I'll wait for Brenspeed's email reply and do some more googlin meanwhile.

Anybody out there tuning their S197 via laptop?

homebrewer · Jul 29, 2007

I also hate the lag time for the engine to return to idle. I'm still running a stock tune for the moment, but it's very annoying. Say for instance, I punch it in first, all the way to the redline. Once I let off the gas and drop it into neutral, it will take a solid 6 to 9 seconds for the engine to return to idle.

I'm under the impression that a tune will fix this, both on accel, and decel. Soon enough I'll find out personally.... I can't wait to order an intake/tune.

Swordsman · Aug 1, 2007

I'm pretty new to the forum and don't actually own a Mustang yet, but this all sounds pretty strange! Why would Ford not deal with these odd throttle issues up front? I've seen posts all over the place about it, so it must be a really common problem...? You shouldn't have to do an aftermarket tune just to get your throttle to perform normally.

Why is everyone going to an electronic throttle, anyway? Seems more trouble than it's worth.

~SM

red05bullitgt · Aug 1, 2007

dawater said:
Yeah, I read it. I was mostly agreeing with you in the start of my second paragraph. But, your post wasn't specific enough for me to be sure that it will fix it. I did email Brenspeed about it--thanks for the suggestion. When most people talk about the throttle lag on these cars, its on acceleration, not deceleration. My lag on acceleration is gone with the tune, and I hate to spend more $$ without being 100% sure.

I'd like to know if the sniper (or other laptop tuning software) will give you control over this decel throttle lag. I'm not sure that I want to do another canned (or custom email order) tune. I come from the do-it-yourself HPTuners world of GM V8's where you have complete control over hundreds of parameters.

I guess I'll wait for Brenspeed's email reply and do some more googlin meanwhile.

Anybody out there tuning their S197 via laptop?

If you're referring to throttle lag decel, also known as a hanging idle, during deceleration ? Then yes ! both Brenspeed and Bamachip tunes, will fix it.. So you can be sure, that once you upgrade to either a Bamachip's, or Brenspeed tune ! you'll no longer have, any further decel issues..And perhaps, if you had referred to your lag issue, as throttle lag deceleration, in the first place ? My post, would've been more specific, to begin with..That being said, I was referring to both throttle lag accel, and decel

05xgt · Aug 1, 2007

no one has however adressed wheather or not a more controlable programing software is available or not, be it laptop or otherwise.

shooterm1 · Aug 2, 2007

05xgt said:
no one has however adressed wheather or not a more controlable programing software is available or not, be it laptop or otherwise.

I've asked the same question here over and over and been told - no - , just as many times.

and I dont get it!

these so-called "Tuner" guys all know how to fix the code, but they all want to sell you their complete package(s) instead.

Its like wanting to get a room for the night and all you can get is an offer to sell you a four bedroom house!

Frank S · Aug 2, 2007

Swordsman said:
I'm pretty new to the forum and don't actually own a Mustang yet, but this all sounds pretty strange! Why would Ford not deal with these odd throttle issues up front? I've seen posts all over the place about it, so it must be a really common problem...? You shouldn't have to do an aftermarket tune just to get your throttle to perform normally.

Why is everyone going to an electronic throttle, anyway? Seems more trouble than it's worth.

~SM

I haven't kept up with modern anti-smog technical developments, but my memory of the time when the absence of compression braking first became apparent and universal is that the reason was the old fashioned way created inordinate amounts of the most noxious substances the machine was capable of emitting.

High vacuum in the intake tract sucked fuel that had no way to burn, as well as potentially pulling oil past the rings and valve guide seal. Or something.

Swordsman · Aug 2, 2007

Frank S said:
I haven't kept up with modern anti-smog technical developments, but my memory of the time when the absence of compression braking first became apparent and universal is that the reason was the old fashioned way created inordinate amounts of the most noxious substances the machine was capable of emitting.

High vacuum in the intake tract sucked fuel that had no way to burn, as well as potentially pulling oil past the rings and valve guide seal. Or something.

Ah, so it may be that the "lag" is actually intentional, then. Hunh. Interesting.

~SM

Frank S · Aug 4, 2007

Swordsman said:
Ah, so it may be that the "lag" is actually intentional, then. Hunh. Interesting.

~SM

Leads to a supposition that eliminating the 'lag' may jeopardize affirmative results in (for example) California's routine biannual smog check inspection.

homebrewer · Aug 5, 2007

I'm sure that the lag is intentional from Ford, in response to emissions requirements. It is annoying, but it can be dealt with.

As far as engine braking goes though... the only time that I use it would be in going down a relatively steep hill. If you're just slowing down on a flat surface, I wouldn't bother. The only real reason to downshift and use the engine as a brake (on the street) would be when going down hill and trying to maintain a constant speed. If you're on flat roads, and engine braking, just remember that brake parts are much cheaper than a new clutch

grendal · Aug 7, 2007

Frank S said:
I haven't kept up with modern anti-smog technical developments, but my memory of the time when the absence of compression braking first became apparent and universal is that the reason was the old fashioned way created inordinate amounts of the most noxious substances the machine was capable of emitting.

High vacuum in the intake tract sucked fuel that had no way to burn, as well as potentially pulling oil past the rings and valve guide seal. Or something.

I can sorta see that potential on a carbed vehicle or an older FI design, but that doesn't make much sense for a fuel injected vehicle. It can't "suck" fuel that hasn't been sprayed from the injectors yet For that matter, if the engine is maintaining RPM's, then in fact fuel AND spark are being used, so again, doesn't add up that it would help with emissions. If anything it would hurt mileage.

I wonder if what some people are seeing is simply the result of a heavy flywheel?

-Michael

dawater · Aug 9, 2007

Yeah, I knew it was intentional. Good to know that we can get rid of it. It may have something to do with emissions, but how does GM do it? I believe its called decel fuel cutoff on LS1's, and its what causes them to pop when you let off. I believe It completely shuts off the fuel on decel.

I got an email back from brenspeed and they confirmed that they get rid of it.

dawater · Aug 9, 2007

Interesting idea, but I doubt it since my GTO was completely different. It probably had a lot more spinning mass than the 4.6. I can't imagine the flywheel is that much different.

If it is, I may get a lighter flywheel...

It just feels like this thing is on cruise control some times. I spent a long time getting rid of that effect when jetting the carb on my dirt bike..

grendal said:
....

I wonder if what some people are seeing is simply the result of a heavy flywheel?

-Michael

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