civic vx coasting

[jmf]

does the vx shut off fuel to the engine when coasting?
i know some engines shut off the injectors when coasting, and use less gas in gear than nuetral.
thanks
justin

[theholycow]

No engine shuts off fuel while coasting, but most modern engines do shut off fuel while engine braking. Coasting is when you're in neutral, engine braking is when you're in gear and the throttle is closed. Even if you're not losing very much speed, it's still called engine braking.

When the fuel is shut off during engine braking, that's called DFCO -- Deceleration Fuel Cut Off. Some vehicles do it more readily than others -- my VW does it immediately under certain conditions, while my GMC requires 8 seconds of engine braking before DFCO kicks in.

I would be very surprised if the VX doesn't DFCO aggressively.

[aalb1]

Originally Posted by theholycow

I would be very surprised if the VX doesn't DFCO aggressively.

This statement is accurate. The majority of Civic ECU are programed to shut off the injectors as soon as they see 0% throttle and are above 900-1250 rpms. The RPM range varies from ECU to ECU but I believe the VX is on the lower end of the spectrum.

Have fun implementing this when you're going down big hills!

[theholycow]

Now that you mentioned those RPM numbers, it reminds me of reports from other users...the RPM threshold is raised when accessories are in use, I think up to 1350 with headlights and A/C both running.

[jmf]

engine braking was what i ment. sorry.

thanks for the answers
justin