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Discussion Starter #1
Ive been calculating my fuel economy recently and ive figured it to be around 15MPG on the interstate just cruising, My car runs pig rich all the time but i cant figre out WHY? i know that MKIII's run rich but i at least expected closer to 20MPG. anyone know what could be causing my poor fuel economy? im getting tired of putting $20-$25 in the tank every couple of days.
 

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Discussion Starter #3 (Edited)
Would there be a code?? i have a digital a/f gauge(which i know is useless for tuning) it reads 1+volts at idle and buries rich under load and reads about .9?? under deceleration.
 

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A Happy Dad
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hmm, the usual boost, vac, or accordian pipe leak comes to mind

I'm getting around 23 if I keep my big toe from wiggling too much
 

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Discussion Starter #5
mdr40z said:
hmm, the usual boost, vac, or accordian pipe leak comes to mind

I'm getting around 23 if I keep my big toe from wiggling too much
well i have full hardpiping and have no leaks there anymore, my gauge reads between 20-25inhg at idle which is normal from what i gather and the accordian hose doesnt leak either so thats why im puzzled, and yeah my big toe hasnt been wiggling much, its been pretty much just cruising down the interstate at a steady 65-75mph.

i may just resort to getting a SAFC2 and pull out some fuel.
 

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i get about 20 mpg on the freeway... and useing a fuel controler, wont make any difference on the freeway. our cars dont run rich on the freeway (at least mine doesnt...)
 

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2/3 HP to the Paws
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Turn up the boost, that'll lean it out a bit. :D

Probably a vac leak or angry sensor. Check for codes, then check for TSRM spec on the o2 and AFM.

On my last MkIII, I got about 21 hwy and anywhere between 8-15 city depending on how hard I clipped the toenails on my right foot with the fan blades.
 
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I drove down the HPF last month. 1 tank of gas exactly from Seattle-ish to Portland and back, came out to 23mpg. I was impressed.
 

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Discussion Starter #11
well after racking my brain last night the only thing i could think of was that my power steering pump is on its way out and making a LOT of noise(sounds like a ford pump lol), could the parasitic(sp) drag cause this?? ive also noticed my car feels sluggish in the low rpm's to me (below 3k)
 
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When you did the tranny swap did you also swap the computer? If you are using an auto comp. with a 5-speed it could run differently due to different fuel and timing curves of the automatic. Someone correct me if i am way off base here.:)
 

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Discussion Starter #14
drjonez said:
if you're reading a straight 1V, the o2 is dead. there isn't always a code for it.....
no it reads .980- .999 under hard deceleration, and 1.??? at idle, but under any kind of load (and im talking SLIGHT hill on interstate boost gauge still reading 10inhg) it just buries the gauge rich (reads 1. off the scale)

ive unplugged the o2 sensor before and it kicked the check engine light and threw out a code.
 

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Discussion Starter #15
hitchhikkr said:
When you did the tranny swap did you also swap the computer? If you are using an auto comp. with a 5-speed it could run differently due to different fuel and timing curves of the automatic. Someone correct me if i am way off base here.:)

yeah im still running the automatic ECU, but even when it was auto. it still ran ungodly rich and sucked down fuel like a Boeing 747. However i didnt have my a/f gauge installed untill i did the tranny swap.
 

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how about a fuel computer, my emanage added about 30 miles to each tank...
 

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"DANNY TANNER!!!"
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maybe your fuel gauge/sender is playing tricks with your mind?
 

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Discussion Starter #19
derK said:
maybe your fuel gauge/sender is playing tricks with your mind?

Not possible since i filled it up drove and filled it again and divided my milage(on trip meter) by gal of fuel it took to refill it.
 
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