Engine braking

[Christ]

If you have a manual, try keying off while braking down a hill. You won't lose p/s or brakes. If auto, try interrupting the injector circuit, and sitting them off manually while decelerating. If you don't physically feel a difference in engine drag, you're already in dfco.

Your LED may be lying, also. If you wired it to check for power, there's a good chance that it is. Most injection systems pulse/switch the ground side of the circuit (ecm input), with a constant power feed, often from some kind of distribution center.

[justjohn]

Okay, I'm back after reading up a little on DFCO. So it looks like it only engages over 2500 rpm for most vehicles, higher for some. So if you have to shoot for 4k rpm after your downshift to insure DFCO surely that's going to be at least a little more wear and tear on the clutch, right? I don't know about you guys, but I only give it enough throttle to keep from killing it when I change gears. (A little paranoid about burning out the clutch - if that wasn't obvious yet.)

My new burning question is, how do I find out when my car goes into and drops out of DFCO?

[Joenavy85]

Originally Posted by Christ

Most injection systems pulse/switch the ground side of the circuit (ecm input), with a constant power feed, often from some kind of distribution center.

as in they make the voltage bypass the injector? that would make no difference, since my LED is wired in parallel with the injector (to both wire leads, not just the power lead and then to ground)

[Christ]

Engine speed isn't what burn you're clutch out, torque application does. If you're really that concerned, learn to rev match before shifting.

[Christ]

Originally Posted by Joenavy85

as in they make the voltage bypass the injector? that would make no difference, since my LED is wired in parallel with the injector (to both wire leads, not just the power lead and then to ground)

No, they have a constant single circuit, but it's pulsed on/off on the outlet side of the injector, which is connected to the ecm. I shouldn't have called it a ground, its a (-) though.

[justjohn]

Originally Posted by Christ

Engine speed isn't what burn you're clutch out, torque application does. If you're really that concerned, learn to rev match before shifting.

So you're saying over-revving the engine by downshifting isn't actually straining the clutch, it's only like if you stay on the gas while upshifting?

[Joenavy85]

i have the LED wired in parallel right at the plug where the wiring harness plugs into the injector, so unless the injector is controlling itself then anytime there is current flow through the injector there is current through the LED

[SentraSE-R]

DFCO is implemented very differently on my two main drivers, FWIW. My 2002 Nissan Sentra SE-R had to be >2500 rpm to enter DFCO. My 2006 Scion xB only has to be >1500 rpm. In effect, the Scion enters DFCO at any speed >35 mph in top gear, while the SE-R only did it >65 mph in top gear. To add insult to injury, once the SE-R was in open loop, it took 4 minutes of engine-on time for it to re-enter closed loop again, negating any benefits from entering DFCO in the first place.

The xB, OTOH, is a DFCO sweetheart. Exiting DFCO, or EOC, it happily resumes closed loop operation immediately.

[Christ]

Yep. That pretty much sums it up. Don't "ride" the clutch, don't apply throttle until the clutch is almost fully engaged. Under normal use, the clutch and components can last the life of the car. If I was near it, It'd show you a picture of a clutch used in my first truck that was changed for the first time at 377,000 miles. The sole use for the truck before I bought it was nothing other than towing a 40foot goose neck RV around the country. I had full service records when I bought the truck, dealer serviced, but only items which failed inspection/testing were ever replaced (scheduled maintenance... Hah!). The transmission hadn't been removed from the truck, proof that the clutch hasn't been altered. I changed it when I installed a new transmission with shorter gears, because the splines were wrong for the new trans. It still had the OEM wear indicator grooves, close to 2mm deep - lots of life left.

[Christ]

Originally Posted by Joenavy85

i have the LED wired in parallel right at the plug where the wiring harness plugs into the injector, so unless the injector is controlling itself then anytime there is current flow through the injector there is current through the LED

So your LED blinks about 1000 times a min?