Getting 8.5 mpg need help

[Scottydoggs]

for sure all gas is not the same, i found that out real fast.

frigging 93 just hit 315 here. im not to happy about that.

 

[HiHoeSilver]

for sure all gas is not the same, i found that out real fast.

frigging 93 just hit 315 here. im not to happy about that.

Wow. I pay 3.25 for 89. The 93 is 3.90

 

[Scottydoggs]

Wow. I pay 3.25 for 89. The 93 is 3.90

it was down to 240 ish all winter, then they added a 22 cent tax, now summers here and of course gas went up as always. for NJ being such a hell hole we still have pretty low gas prices and we cant pump our own gas, so full service at that price.

so a 60 cent gain is a kinda a hit. this just makes me drive my regal more sadly. im tuned to use meth injection. glad i got 14 gallons sitting here, ill kill a gallon over 2 weeks time just driving to work, and the only place to buy it is at the track. i run 93 im the hoe too. but the hoe drinks it faster. so little hot rod it is......14 gallons just cost me 42 bucks. that will last me a month roughly.

 

[BlueCollarTahoe]

Compared to your left bank of cylinders, the right was further away from ideal. Just take another reading like you did last time.

I had no perceptible power loss, no flashing CELs, no misfires, etc. when my cats started throwing codes. When we took off the right one, we could see it was falling apart. My mileage has been steadily improving since.

okay cool so heres an update. i hooked up the ancel and the torque pro with the bluetooth adaptor to compare and the numbers were the same. i took a bunch of screenshots from when i left work, highway driving..car off..then at idle again. i found a table of whats considered the various loads to diagnose the fuel trims properly so tomrroow i have those numbers in the proper loads.




now thats not my car that was some caer they used but now i see whats the different load amounts and can get that. but i did notice something...at idle after i parked for the night
STFT1: -0.78
LTF1: 7.8
LTFT2: 9.4
STFT2: -2.3%


arent these numbers supposed to be as close to 0 as possible at idle?


earlier in the day after the highway driving:
LTFT1:0.8%
LTFT2: 0.8%
STFT2: 2.3%

also ive gotten a PO455 CODE on and off...i replaced all the compnents and the gas cap in the evap system and still get it once in a while. saw this in the Emissions rediness s/DTC table:

Evaporative system: incomplete
02 Sensor incomplete

the rest of them ) misfire/fuel systemm compnenets, catalist) said complete or not availble. now i know if i got a large leak somewhere then yea the evap system may not be complete but the 02 sensor being incomplete? or are they connected? i also have 1/4 gas tank today i think ir ead somewhere the tank needs to be 3/4 or full for the evap system to work properly not too sure about that tho.

 

[Scottydoggs]

evap and the o2 can take a while to become "ready". like days even.

your trims really dont seem all that bad, they come with a lean ass tune stock. mine was +8 all the time before i tuned it.

when on a cold start the trims are not true. the engine is running off pre set settings till it warms up, then it runs off the sensors. and then trims are really what they say.

we no longer have a choke, so the pcm adds fuel to make it run when cold, so you get that high idle as well. why the trims got neg numbers on the cold start.

 

[swathdiver]

The one thing I see compared to last time is that his right bank is a little off from his left. So was mine when the cat was on. Haven't really monitored it since that last posting. Heck, haven't drove it in weeks.

 

[BlueCollarTahoe]

well may turn out just to be city driving getting me....but i will post all the trim numbers monday hopefully. been a long couple days.

 

[sonic_the_hedgeh]

so for a while i been getting more or less 8 mpg. when i fill the tank it usuallt says around 208 210 estimated miles. last tank i got 218 before i chickened out and filled up. i run all terrains on the factory 17. nothing crazy. i think this is low. i took it to my shop the guy the said the computer was all messed up and reprogrammed it. it worked some i was getting another 1/4 tank more or less. but even for city driving it still feels low. where do i start to figure this out? is this just the truck or is something wrong?

I would try seafoam intake cleaner. Safe to use and it could help.

Sent from my SM-G935W8 using Tapatalk

 

[BlueCollarTahoe]

I would try seafoam intake cleaner. Safe to use and it could help.

Sent from my SM-G935W8 using Tapatalk

have done it before didnt make a difference.

 

[BlueCollarTahoe]

UPDATEs with fuel trims:

idle with car at op temp:
STFT1: 0.00
LTF1: 4.69
STFT2: -0.78
LTFT2: 8.59


25 MPH:

STFT1: -3.12
LTF1: 8.59
STFT2: 4.69
LTFT2: 11.72


45 MPH:
STFT1: -3.12
LTF1: 9.38
STFT2: 2.34
LTFT2: 11.72


65 MPH:
STFT1: -4.69
LTF1: 11.72
STFT2: 1.56
LTFT2: 14.06


then noticeed crusing around 50 mph:

STFT1: -6.25
LTF1: 17.19
sTFT2: -3.12
fTFT2: 17.97


now i been having on and off an evap code, PO455 and ive changed all the hardware in the system ( the canister/vapor things the one in the engine bay and he one next to the canister)


i looked in he vehicle test results on torque pro and sawe that i got a NOT OK on the lean to rich sensor thereshold
min:32878
current 32771



any ideas where to look from this info?