Trans Control
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Senior Member
Joined: Feb 2002
Posts: 1,002
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From: Newark,CA
Trans Control
I am posting this under computer chips rather than in the transmission forum because I am sure the answer is computer related.
I have noticed that when I lift off the throttle, particularly on the freeway, that at first my truck barely slows but after about five seconds it is almost like I turned off the ignition. The exhaust note significantly changes and I can feel more decelleration.
Can anyone explain this and can I change it?
I have noticed that when I lift off the throttle, particularly on the freeway, that at first my truck barely slows but after about five seconds it is almost like I turned off the ignition. The exhaust note significantly changes and I can feel more decelleration.
Can anyone explain this and can I change it?
Former Sponsor
Joined: Mar 1998
Posts: 13,385
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From: Virginia
Hi Mad,
Sounds like normal torque converter lock/unlock characteristic under deceleration, and is supposed to happen. When you come off the gas for long enough (and it doesn't take long), the TQ will unlock, providing more compression braking, also more torque multiplication for better acceleration when you put your foot back on the gas, before it locks back up again.
That's not something you really want to change in the powertrain program, as it can easily have a negative impact on TQ lock/unlock in other situations if approached casually. Of course just about anything can be done given enough trial & error R&D, so I suppose that could be adjusted in custom programming, but I wouldn't.
If you want to give us a call we can go over that a bit more with you, but I think what you are describing is just the perfectly normal TQ lock/unlock cycle under those conditions.
There are a few people who are **** about this (and all of us vehicle-nuts are **** about something!) and will install a manual switch tied into the circuit/wire controlling current sent to TQ for lockup to achieve more manual control over this. That's fine for them, me personally I'm not a fan of that either, to each his or her own, of course, the TQ lockup doesn't bother us, & is generally well suited to the characteristics of these vehicles & their uses.
Sounds like normal torque converter lock/unlock characteristic under deceleration, and is supposed to happen. When you come off the gas for long enough (and it doesn't take long), the TQ will unlock, providing more compression braking, also more torque multiplication for better acceleration when you put your foot back on the gas, before it locks back up again.
That's not something you really want to change in the powertrain program, as it can easily have a negative impact on TQ lock/unlock in other situations if approached casually. Of course just about anything can be done given enough trial & error R&D, so I suppose that could be adjusted in custom programming, but I wouldn't.
If you want to give us a call we can go over that a bit more with you, but I think what you are describing is just the perfectly normal TQ lock/unlock cycle under those conditions.
There are a few people who are **** about this (and all of us vehicle-nuts are **** about something!) and will install a manual switch tied into the circuit/wire controlling current sent to TQ for lockup to achieve more manual control over this. That's fine for them, me personally I'm not a fan of that either, to each his or her own, of course, the TQ lockup doesn't bother us, & is generally well suited to the characteristics of these vehicles & their uses.
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Senior Member
Joined: Feb 2002
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From: Newark,CA
Mike,
Your response is interesting, though I am not sure it is accurate. However, I will investigate further now that I have a possibility to prove or negate.
As far as the converter lockup goes, just call me ****.
I have been driving a Typhoon for the past nine years and the first thing I did was put a manual over ride on the converter. I'll grant you that a turbocharged engine is more sensitive but at 30 mph in fourth lockup (1400rpm) when you gave it a little gas virtually nothing happened until the converter unlocked and flashed, giving boost and suddenly that little gas became too much. As a matter of fact, I drove around town in third, unlocked so that there was always plenty with just a nudge of the pedal.
My F-150 is almost as bad, I already drive it out of OD but I am still going to figure out how to manually over ride the lockup so that I don't have to make a downshift or whatever when I want to pass or change lanes at 30 mph.
Your response is interesting, though I am not sure it is accurate. However, I will investigate further now that I have a possibility to prove or negate.
As far as the converter lockup goes, just call me ****.
I have been driving a Typhoon for the past nine years and the first thing I did was put a manual over ride on the converter. I'll grant you that a turbocharged engine is more sensitive but at 30 mph in fourth lockup (1400rpm) when you gave it a little gas virtually nothing happened until the converter unlocked and flashed, giving boost and suddenly that little gas became too much. As a matter of fact, I drove around town in third, unlocked so that there was always plenty with just a nudge of the pedal.
My F-150 is almost as bad, I already drive it out of OD but I am still going to figure out how to manually over ride the lockup so that I don't have to make a downshift or whatever when I want to pass or change lanes at 30 mph.