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Old 05-22-2008, 07:07 PM   #1
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my pulse and glide findings

Well, my scangauge was a bit misleading. I worked my you know what off pulsing all over for a tankful, and got about the same as always despite the scangauge saying otherwise. for my car, and the techniques I used, its not work the effort. I just keep getting 34mpg tanks no matter what I seem to do. I guess I'll have to live with that. Not so bad, just not as much as I would have liked, but I did get the less efficient model. So leaving the car idle while gliding doesn't seem to work very well with a '02 Civic Si, at least not for me.
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Old 05-22-2008, 07:26 PM   #2
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Does the Scangauge read correctly if you drive "normally"?

Is it staying open loop?
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Old 05-22-2008, 09:04 PM   #3
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It takes a while to really learn P+G. I'd reccomend that you keep trying for another tank or two and try to improve your technique. With some practice you should be able to recognize gliding opporitunities further ahead of time, and be able to glide longer distances.
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Old 05-23-2008, 03:44 AM   #4
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It might be worth trying to diagnose what's going wrong.

I think in another thread I saw you say you shift at 4000 rpm. Try cutting that in half, or more.

How's your tire pressure?

What does a typical P&G cycle look like, as far as max and min speed? What's your typical top speed, in general? Do you often need to come to a complete stop?

How much do you typically open the throttle? As fume said, is SG indicating open loop? Try this: open the throttle as much as you can, without inducing open loop. Shift early (2000 rpm or less). Keep revs low. Is this what you're already doing? If not, try it and let us know what happened.
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Old 05-23-2008, 06:39 AM   #5
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Originally Posted by monroe74 View Post
It might be worth trying to diagnose what's going wrong.

I think in another thread I saw you say you shift at 4000 rpm. Try cutting that in half, or more.

How's your tire pressure?

What does a typical P&G cycle look like, as far as max and min speed? What's your typical top speed, in general? Do you often need to come to a complete stop?

How much do you typically open the throttle? As fume said, is SG indicating open loop? Try this: open the throttle as much as you can, without inducing open loop. Shift early (2000 rpm or less). Keep revs low. Is this what you're already doing? If not, try it and let us know what happened.
I concur with Monroe and the others. Keep at it. It took me the better part of a month to figure it out with my Camry. I also have a "check engine" light that comes on every now and then, I need to get that checked out - could be something wrong that is impacting my MPG.
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Old 05-23-2008, 10:11 AM   #6
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My first P&G tank was also disappointing. Tonight I'll know how my second is doing, but it looks like it will be good.
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Old 05-23-2008, 03:18 PM   #7
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Originally Posted by fumesucker View Post
Does the Scangauge read correctly if you drive "normally"?

Is it staying open loop?
Yes! I believe its a somewhat slow polling rate, and doesn't always catch my pulses, so it makes the MPG #'s go up, quite a bit. With my crappy pulsing, and gliding, it missed about 1.4 gallons. Otherwise when I drive nice, it seems really close. No on the open loop thing. and other have suggested shifting lower, yes I usually do that, but its an Si civic, so if I try to keep the revs below 2k, I can only go 40 mph. Not good on the highway. I love the car, and am very happy with the 34 mpg I am getting. EPA old #'s say 26 average. So its not doing bad at all!
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Old 05-23-2008, 03:30 PM   #8
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if I try to keep the revs below 2k, I can only go 40 mph
I didn't mean keep it below 2k in top gear. I meant mainly in the lower gears. Somewhere I think you said you were shifting at 4k. But you're right, the mileage you're getting isn't bad.
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Old 05-23-2008, 04:41 PM   #9
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Well, the results of my second P&G tank are in. 34mpg! New record for me!

I didn't P&G on the highway, and I think that helped. With my weaksauce low top gear I lose a lot at 3000rpm on the highway, but I lose more trying to rev-match 3000 rpm repeatedly (due in part to the car's peculiarities, and in part to the fact that I suck at rev-matching).

On the highway, I did P&DFCO -- just on and off the gas pedal, leaving it in gear. Generally my P&DFCO cycles were ~10mph. It doesn't save engine frictional losses, but it does save pumping losses and prevents having to feed fuel just to make the engine keep up with the car.
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Old 05-23-2008, 05:21 PM   #10
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34mpg!
That's great. Congratulations.

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On the highway, I did P&DFCO -- just on and off the gas pedal, leaving it in gear. Generally my P&DFCO cycles were ~10mph. It doesn't save engine frictional losses, but it does save pumping losses and prevents having to feed fuel just to make the engine keep up with the car.
When you're in DFCO, you're not just paying for engine friction. You're also getting unwanted engine braking because the motor is acting as an air pump. So it would be great if you could do real coasting instead. Or maybe that will only work for you at lower speeds. Or maybe you can just try it on a long downhill grade, where the long glide will justify the effort of getting it in and out of neutral.
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