whats up with the bad mileage?

[Yo'J]

Alright! Got data! 26.5 mpg with140 main, 2/3s highway driving.

 

150 main is too big! She runs steady in the rich on cruise, very steady! I'll bet the 145 would be perfect as the 140 left me off the scale lean. The power difference is huge! Well sort of...it just doesn't have that dry feeling any more, like it needed monostat7 or something! I wont get a good reading on mileage for a little bit, she needs to be driven and I'll be in town for the next week at least. You know 5 stops in two miles there and 4 stops in 3 miles home. I'll make sure everything is tight and steady, then drop in the 145.

 

She still bogs/fuel starves at WOT around corners like on ramps, maybe worse now:grin: ! And of course the other problems that are currently showing up!

[Yo'J]

O.K. 140 main jet back in for the last few days. I've noticed a few things. The gauge jumps from off the scale lean to rich all the time at 30-40 cruise. One trip down the highway only does so good. So I guessing(I know I do a lot of that), that I was reading this thing wrong. The weber should just sip the gas when needed right? Meaning when it is off the scale its just not reading a lean condition, its a reading a coasting condition,i.e. no throttle. Should an engine stay in the stoich during most driving situations like slow acceleration? If so I would need to go with a 135 main or smaller, then I would not be running so rich when I am at cruise. If that is true, then would I want to match that secondary as well? Am I trying to stay stoich at WOT as well?

[GeneralDisorder]

O.K. 140 main jet back in for the last few days. I've noticed a few things. The gauge jumps from off the scale lean to rich all the time at 30-40 cruise. One trip down the highway only does so good. So I guessing(I know I do a lot of that)' date=' that I was reading this thing wrong. The weber should just sip the gas when needed right? Meaning when it is off the scale its just not reading a lean condition, its a reading a coasting condition,i.e. no throttle. Should an engine stay in the stoich during most driving situations like slow acceleration? If so I would need to go with a 135 main or smaller, then I would not be running so rich when I am at cruise. If that is true, then would I want to match that secondary as well? Am I trying to stay stoich at WOT as well?[/quote']

 

Ok - so yesterday I installed my wideband/controller on my Weberized '83 hatch.

 

So here's what I found.

 

1. It likes to idle rich. I can adjust it to 14.7 or so, but it really doesn't like it. It likes around 13.0 or 13.5 but is still a bit rough. When I first booted it up my "intuition" had it tuned to 11.5 or so. That's where it likes to idle smooth.

 

2. Part throttle cruise is off the scale lean. That's OK because you're really not making any power - very light load on the engine means it can handle the lean condition without damage. It's also great for mileage. I may need to calibrate my sensor again but flat & level freeway at 50 to 55 MPH is over 16:1 on my meter. For that matter so is 60 or 65 MPH, but the engine RPM is higher so fuel consumption would still be greater. I think my calibration is a little off though so it may be 15.5 or so in reality. I'll know for sure when I calibrate again.

 

3. A slight amount of throttle will pull it right into the stoich area of 14 to 15, and a bit more will quickly pull it down to 13.5 or less.

 

4. Under closed throttle (even a little bit of deceleration) it goes slightly richer than if you leave the throttle cracked just a bit. So if you stay just slightly on the gas going down a hill on the freeway you can keep the engine leaner than if you let off and decelerate. On a slight downhill I might pickup 5 MPH or so doing it this way, but it doesn't go rich. I would like to try hooking up the AAV from the Hitachi, or another closed throttle coasting vacuum release valve just to see what kind of difference it would make in this scenario.

 

5. I can say without reserve that just in the 30 miles I've driven with my wideband I could easily make back the investment in the thing in fuel savings. Not only from tuning, but from watching it as I drive - it's both a good reminder to slow down and not accelerate like a madman all the time, and it's a challenge to keep the thing as lean as possible by watching the gauge. It sounds steep at $260 (for mine), but when you consider the cost of a tank of fuel these days - I'm shelling out $45 to fill my hatch and it's always less than 10 gallons! If I save just one gallon of gas per tank by having it there to show me what I'm doing wrong while I drive then at current gas prices it will pay for itself in just over a year.

 

GD

[daeron]

5. I can say without reserve that just in the 30 miles I've driven with my wideband I could easily make back the investment in the thing in fuel savings. Not only from tuning, but from watching it as I drive - it's both a good reminder to slow down and not accelerate like a madman all the time, and it's a challenge to keep the thing as lean as possible by watching the gauge. It sounds steep at $260 (for mine), but when you consider the cost of a tank of fuel these days - I'm shelling out $45 to fill my hatch and it's always less than 10 gallons! If I save just one gallon of gas per tank by having it there to show me what I'm doing wrong while I drive then at current gas prices it will pay for itself in just over a year.

 

GD

 

Sold, at least on the narrowband front. Delivering pizzas burns through 5 gallons a night. If I can save 2 gallons a week then the rest of the year (at only $4/gallon) is well over $200. If I pull even 1/4 those savings just thru the "reminder" feature....