midiwall

'k... Remember that the gas gauge is a lousy indicator of how much you actually have left in the tank. The "half way" point can be +/- 2 gallons off due to the ballistics of the meter. That zone is very wide in terms of where the sensor really is in the tank.

The only valid way to figure out mileage is to fill the tank (defined as you stop pumping after the pump shuts off by itself), then driving, and filling up again. The amount you fill up with is the only real indicator of how much fuel you used.

99SR5

iTrader: (1)

ok i just bought gas at 140 miles. i might have gone to 150 but that would have been ballsy

midiwall

'k... so, how much did you put in?

99SR5

iTrader: (1)

um... like 13 gallons. i bought my new 02 sensor and hopefully the post office will bring it by again because i missed it today

fireteacher

i have a spare MAF, used..bought it off of ebay and never installed it..50 bucks and its yours

99SR5

iTrader: (1)

na its ok i cleaned my MAF. i sprayed that sucker for a while

2000t4r

I'm interested in your, can you please PM so we can work out the details.

99SR5

iTrader: (1)

so when i install it do i have to disconnect the battery or take out the EFI fuse or just throw it in.

midiwall

You should always reset the ECU when doing anything that can change the engine performance. Air filter, fuel filter, O2 sensor...

And, like we've talked about, you can reset the ECU by pulling the EFI fuse or disconnecting the battery. The upside of doing the EFI fuse is that you won't lose your radio presets and the clock will keep time.

Do either one for a minute, then hook it back up and go. Go fill the tank, reset the trip odometer and let use know how things feel the next time you fill up.

99SR5

iTrader: (1)

sweet thanks alot

99SR5

iTrader: (1)

ok well i finally installed the sinsor and i gotta say that working on a truck with an a$$ load of mud under it is a pain, but i got it in and i pulled the EFI fuse for 60 seconds and reenstalled that. anything else i should do. i didnt have torque wrench so i just got the nuts on there snug. Is that ok?

midiwall

Yeup... In fact, you can OVERtorque those bolts pretty easily - you want to be careful. If the sensor is pulled flush to the flange then you're fine.

Go fill 'er up, then check back after blowing through a tank full.

99SR5

iTrader: (1)

ok well im worried becuase i have gone about 15 miles and im between full and 3/4 full. is this normal. i disconnected the battery today for at least half an hour to see if the computer didnt reset when i just pulled the fuse

midiwall

"Normal"? Well, did it do that before? i.e., is this a new symptom? (it sounds "fast", mine usually sits in that spot at about 25-30 miles)

Remember, the fuel gauge SUCKS for figuring out usage. If you want, head to a pump, top it off, and let us know how much you put in. But, a clean reset on an ecu will generally run rich, so it may be okay.

You really just want to see how this complete tank goes.


'k, but don't pull it again. The ECU needs to adjust to things, if you keep pulling power and it keeps resetting then it won't have time to settle in.

99SR5

iTrader: (1)

oh so it will take a while to completly reset. ok ill use up that tank and let you know

midiwall

Umm, not to get tied up in semantics, but It will _reset_ in about 10 seconds when you pull the power. It will resynch/readjust/recalibrate/relearn over a period of time, at least 100 miles of _mixed_ driving (city & highway). It's the latter one that you're waiting on.

99SR5

iTrader: (1)

ok well i guess i got to start driving

midiwall

yeup. And you want a nice mix of city & highway. The ECU "maps" cover about 100 grid points from idle to high RPM no load (coasting downhill in gear) to low RPM high load (chugging up a hill), etc. You can to show the ECU a lot of variable driving in order for it to learn how to get the air/fuel mixture right across the board.

But that also says that you don't need to go looking for terrain that you don't normally drive. Just drive as you always do, and don't think about it.

See you in 200 miles or so.

gpcollen1

me thinks you did not even fill the tank up all the way...

midiwall

(based on 99SR5's comments at: https://www.yotatech.com/forums/f2/random-stall-85409/)

Ummm...

There _is_ a cut off at redline on an auto, it's ignition & not fuel, but it can defnitely show similar symptoms.

Then, given that you're complaining about poor mileage, I've gotta ask... How often do you bounce off of the rev limiter as you drive??