Open Loop/Closed Loop

[JockoT]

Originally Posted by trollbait

Never thought to monitor temperature and loop together

I have just been playing with all the things the ScanGauge can display, just to see if anything is of use to me!

[R.I.D.E.]

I'll check the next time to see when my ultragauge shows closed loop from a cold start. I would be it's probably fairly fast, probably a heated 02 sensor. I have done so much EOC on some local routes I don't reach operating temperature in 5 miles.

[JockoT]

Driving slightly different today, as I took Mrs Jocko to work. Noticed that as soon as Closed Loop is active, so too is DFCO, but only at slightly higher rpm. When in Closed loop at 1500 rpm with a warm engine DFCO is operative, however with a cold engine it drops out below 2000 rpm.
Today I was revving a bit freer and changing up at a slightly higher speed, which meant that in turn I was coasting in gear from a slightly higher speed. Fuel figure for the morning 4 miles was a bit better too.
Honda Jazz has a very small throttle movement. While monitoring the Throttle Position Sensor (which reads from 12 with foot off to 85 at full throttle) I observed that it reaches full throttle (85) long before the pedal reaches the metal. I have always found the throttle very finicky and this explains why. The "drive by wire" throttle has a very small range. I think it would benefit from being driven without shoes.

[trollbait]

Throttle by wire doesn't have to be limited to controlling just the throttle. The TPS readings and physical pedal position from my Sonic are similar to what you experience. I have found that continuing to depress the pedal past the point where the TPS maxes out leads to increasing boost pressure from the turbo.

Posters on a Sonic forum describe the accelerator as a torque demand pedal. How far it is pushed tells the car's computer how much torque you want, and it adjusts things to provide it.

[JockoT]

On the Jazz the throttle is only connected to the TPS, nothing else. That means that the ECM only uses the TPS signal. It doesn't have a turbo so requires no further input.

[trollbait]

I thought TPS is just monitoring the throttle, or whatever that is in diesels, not the pedal. So the the ECM could be monitoring something else to see how far the pedal is depressed in a throttle by wire system.

I didn't know that it was still possible to get a turbo without a turbo. The few personal vehicles options we have got them.

[JockoT]

The throttle pedal is connected to the throttle pedal sensor by a Bowden cable. As you push down the pedal it changes the resistance of the sensor. That signal goes to the ECM, which controls the position of the throttle flap by a motor mounted on the throttle body.
The GD version of the Honda Jazz is not available with a turbo. It has a 1.2 or 1.3 litre normally aspirated engine. Mine is a 2006 1.2i-DSi.