Recently bought a Mach 1. Love it, but one thing bugs me. When you let your foot off the throttle in neutral or with the clutch disengaged the revs fall slowly - not as you'd expect in an engine with 10:1 compression. I suspect it's either a function of the engine management sytsem or a physical damper on the throttle butterfly itself. It makes smooth upshifts hard work. Anyone know how to restore some "snap" to the throttle response? If it's a damper can it be removed / disabled? If it's the EMS do any of the aftermarket chips change it? Thanks,
Mach 1 throttle behaviour
Feb 04, 2004
4 Replies
It's a function of the ECM and it's to prevent eccessive engine braking. I would imagine that you could change the program with some kind of software, but it would just be for cool points.
Marc
It is done to keep emissions down. If the throttle would shut fast it would cause a vacuum downstream. This vacuum pulls in all fuel that was collected on the walls of the intake (it vaporizes I think) and this causes a blip of bad emissions. By slowly dropping the revs you won't have this happen. Only way to 'fix' it is to change the ecu programming. Remove NO-SPAM from email address when replying
** Recently bought a Mach 1. Love it, but one thing bugs me. When you let your
** foot off the throttle in neutral or with the clutch disengaged the revs fall
** slowly - not as you'd expect in an engine with 10:1 compression.
** I suspect it's either a function of the engine management sytsem or a
** physical damper on the throttle butterfly itself.
** It makes smooth upshifts hard work. Anyone know how to restore some "snap"
** to the throttle response?
** If it's a damper can it be removed / disabled? If it's the EMS do any of the
** aftermarket chips change it?
Some of this is due to ECM programming to lower emissions. A dirty MAF element will make the problem worse. This can also cause preignition problems. Try removing the MAF element and cleaning it with a blast of CRC chlorine-free electrical contact cleaner spray.
Regards,
-JD
--------------------------------- JD's Locally-Famous Mustang Page: http:/207.13.104.8/users/jdadams---------------------------------
Your best bet is to learn to live with it. Cars these days do it--especially manual trans cars. It keeps hydrocarbon emissions down. My 2000 GT does it, my Audi does it, and I've just gotten used to it. In time, the smooth upshifts will be a no brainer--and you may learn to use it to your advantage.
Enjoy
Vic
2kGT 5m blk suspension upgrades
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