Am I on to something?
 

When a section of pipe came off my exhaust, I had to drive a lot softer to avoid being obnoxiously loud. I noticed that if I get up to speed relatively quick, then just barely add enough gas to go, the exhaust stayed pretty quiet. The trouble was, I was very gradually slowing down. Any more gas and it was a bit loud.

I ended up driving half the tank with the exhaust open, then went on the freeway up to the local drag strip. I drove faster than usual on the freeway and made a couple passes at the strip. I was going to test some intake setups and have quantified results, but something didn't sound right after the second run, so I called it a day. Haven't heard that sound since, but I didn't want to risk breaking something.

Even after all that, I got 26.4 MPG, matching my last best tank. When I got the pipe back on, I didn't concern myself with working the throttle that carefully, but the other day, I decided to try it again, bringing it up to a little above 55, then letting off te gas enough so it's decelerating at a very slow rate. I noticed the needle on the gas gauge didn't move much at all after the usual 20-mile commute to the nearby city.

I'm thinking of this as a modified "pulse and glide," since I'm using very little power to keep the car going on the "glides."

It's been a little over 200 miles this tank, and I still have just under 1/3 of my fuel left. I'm wondering if this is going to be a record tank!

So, am I on to something here, or just discovering on my own what everyone else already knew?

You're pretty much P&Ging.

I tried this technique to much benefit recently. The weather was unbearably hot, and I had to go some 200 miles at a stretch. I was forced to keep the AC on, and therefore EOC coasting was not possible. I just decided to 'micro-P&G' - get up to 80 kmph, let the car come back to 75 on DFCO, then add a gentle burst of power to push it back to 80, DFCO to 75, rinse and repeat.

I got 47, without shutting off engine at all, at a respectable speed of 80 kmph.

Since then this has become my fallback option if I cannot do EOC coasting. (the entire summer months are 'fallback', with some exceptions).

Over on CleanMPG, this is known as "Hang Time" and it's VERY effective. :)

No wonder my last 3 tanks were around 25 or better. XD

Thanks guys!

Do you have an automatic transmission?

I use my AC a good deal in hot weather too. What I've started doing is to get the car cool, make sure the recirculate button is on so I don't start miing the hotter outside air, turn off the AC button and turn up the fan speed. For my 20 mile commute, this cuts my AC usage by about 1/3 and I stay relatively comfortable the entire time.

Madison: Yes, it's a 3-speed auto, and I can barely stand it. Though I can get it to short-shift by itself if I barely touch the throttle, but I'm crawling forward with all the speed of a slug. I only do that if there's no one behind me. This tranny makes the engine spin at 3K RPM around 60 MPH.

gasstingy: I actually removed the AC compressor at the same time I removed the power steering.

hang time, haha i like that. I drive a manual and just pop it in neutral to do the same thing. Do you put it in neutral to glide when you do this on an automatic? you said 3000rpms so I gues not. If you can, I feel like shifting in to neutral on your automatic for coasting would get you even better FE, as you should coast farther if your wheels arent turning your engine.

I'm not actually coasting for this, but barely touching the gas so it's just barely slowing down, maybe a half a mile per hour every 10 seconds, and I hold that throttle position until it drops to around 50.

Interesting... Hang time, will have to try it.

Here's the post over on CleanMPG:

This says you need instrumentation for it, but I've been going by feel and ear. Except with non variable-valve-timing engines, there are mixed results as to whether this works or not. But after using this technique with two passes at a drag strip and some fast freeway driving, and still rubbing up against my best tank, I think it can still work for non-VVT/VTEC cars.

Madison: FYI, it's not pulse and glide if there's no glide. Glide = transmission in neutral.

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My bet is you simply drove more conservatively overall due to the open pipe, and your improved fuel economy isn't simply from this one tactic.

Personally, I've tried "pulse and bleed" several times in my own non-lean burn, non-hybrid, non-vvt car, and found no benefit over simply driving with load (DWL).

Sounds just like what I do a lot.

This is the method I use on my Buick to net almost 40mpg, its very odd and seems to only occur on automatic vehicles, MT it doesn't happen.

Its reverse of DWL in that you allow the car to slow (very slightly) on flat or inclines and for me was much more effective than DWL. I also would accellerate when needed on flat ground or down inclines if needed and still DWL'd as much as I could up the incline but needless to say on an auto you can't DWL up long hills the whole way.

My foot would get tired because the motions were so small, but I could maintain speed barely for tremendous distances while getting about 10mpg better FE on the guage

Something to try on an auto I guess. It doesn't really work on my dodge because the thing slows down like it has a parachute behind it.

I wish I could get the tranny to stay in high gear at lower speeds, but since it's an auto, it won't. I guess this could be a trick to get automatics to give better mileage!

I need to pick up a scangauge or something so I can actually quantify this.

...MPGuino. ScanGauge won't work in pre-ODB-II vehicles.

Interesting. I must be bleeding speed too quickly. I'll have to try this on my next long trip.

Aeromodder, you may have the same circuitry in your car as my escort has. (with lean burn)... I've only found a thing or two on the internet about it; apparently Ford called it LOC (Lean On Cruise).
Mpguino and others' wide band O2s have verified this; when the car's warm and in closed loop for a few seconds at light throttle and at speed, it re-enters open loop and increases AFR (air to fuel ratio) up to around 17:1 (If I remember correctly).
If I watch my iMPG on my MPGuino on a flat stretch while going 60-ish mph, I see numbers go between high 30s and mid 50s when this switches on and off.

My goal is to get the car aero and low engine drag enough to do this part time thing at 65-70 mph and all the time at 55-60 mph - would let me get into the 50s.

sources...
 

The Yeager's Ford Escort LX Wagon
March 2005 post

Ford Escort Owners Association

There's also an EPA bulletin mentioned about emissions and the escort's lean burn, but it's been taken offline since it was linked anywhere. I have all the emissions sniff test results; the car always performed way below regulations!

Apparently it's not a new thing; there's mention online of it being on GMs around the 90s

I'll look into that. I don't know if the Tempo's 2.3L has the same setup your 1.9L has, but I'll do some research into it.

Update: It's been 230 miles since I filled the tank, and I'm just now getting to a quarter tank. Usually I'm at the 1/6 mark or coming close to E by now! A quick estimate puts me at 27 MPG for this tank, but we'll see what the final number is when I fill it up sometime next week, probably Monday night.