Deceleration springs, disassembly

[DeloreanJapan]

Short answer, Yes.
Long answer, a while back an owner had an aftermarket exhaust and he wanted it to sound louder. We spent the day playing around with the decel springs. During our experimentation we tried all different springs. We finally settled on some cut down springs from retractable pens. The decel plates/springs are only necessary for the 5-speed, you do not need them for an automatic. BTW, when they built the Deloreans, the engines were all set up exactly alike no matter if they went into automatics or 5-speeds. Typically the vacuum advance, mechanical advance, timing, idle speed, and fuel systems are set up just a bit differently but not in Deloreans! You need the decel valves in a 5-speed because, in 5-speeds, the motor is tightly coupled to the transmission, if you downshift, the motor's RPM's go up a lot. If you do that with a closed throttle, the engine acts like a brake and you slow down fast. In an automatic the torque converter allows the motor to slip so you don't have that huge braking effect. Same if you suddenly lift your foot off the throttle at high speed, you get a large braking effect from the motor. The decel valves allow air to get into the motor reducing the braking effect. If you get backfires you fry the very thin wire of the decel springs. On some cars I have seen them so bad they can't hold the tiny valves shut tight so you can't control the idle.

Hi David . in another words , if you blocked this whole for the decel spring , the engien will get more braking force when off the gas pedal?
I have an Auto trans, Wish the Engine brake force can be more strong ,to reduce foot brake buring the moutian downhill run.

[David T]

Hi David . in another words , if you blocked this whole for the decel spring , the engien will get more braking force when off the gas pedal?
I have an Auto trans, Wish the Engine brake force can be more strong ,to reduce foot brake buring the moutian downhill run.

You can experiment with them and try blocking them shut but I don't think you will get much braking force in an automatic.

[82DMC12]

if you want to experiment with blocking off the decel springs you can seal them closed with a hot glue gun. I did this while troubleshooting an idle issue last year. No, I did not drive the car like this though...

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