Decelerating in gear. (manual T)


Asked by Oct 16, 2015 at 08:33 PM

Question type: General

when you leave the car and release the gas pedal is the "breaking" you feel form the engine, due to the throttle plate closing and creating vacuum in a sense and making it harder for the engine to suck air in correct? (also mechanical friction?)  if im on the right track when you u do this is gasoline still being injected, and the coils still firing?

7 Answers


Gas still enters the engine and the coils still fire in the same amount they would at idle in neutral....its compression and mechanical friction slowing the car


If you have a OBD2 system under full deceleration the injectors do turn off, you can watch this with a live data scanner, but the coils still fire as an emission monitor program. HTH

1 out of 1 people think this is helpful.

Ok awesome thanks guys! :) I have heard that before that it's compression but how is that?? Cuz ur not giving gas anymore..? So it the compression vs the piston in a sense..? Also what is HTH?


HTH, Hope This Helps. Compression is the air that is trapped when the piston comes up to TDC on the firing stroke of the piston. Got to: p=How+an+engine+works&fr=ymyy-t- 999&fr2=p%3Amy%2Cm%3Asb

1 out of 1 people think this is helpful.

thanks guys muchly is it in an automatic transmission is it the same???

1 out of 1 people think this is helpful.

Yep. the difference is in the way the power is transmitted, standards are via the clutch, automatics via the torque converter. Now you can get all involved with different torque curves, cam duration and lifts in standard transmission engine VS automatic transmission engines but thats getting way ahead of ourselves.

1 out of 1 people think this is helpful.

Lol ok thanks boss! :D

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