Lets talk Sensors..
Thread Starter
Teching In
Joined: Mar 2011
Posts: 15
Likes: 0
From: South of Atlanta GA
Lets talk Sensors.. OK, i have a not so simple question, with i am sure of it, a not so simple answer.
My car:
02 Trans Am Firehawk LS1 A4, 3.23 gears.
stock engine stock tune (tune validated by GM when they flashed my PCM).
Long tube headers, Corvette 02 sensors (longer wires) full 3 inch exhaust (unknown brand).
i get about 14-16 mpg in town, and 20-22 on highway (70-75 mph).
my question is... What sensors, aid in fuel metering... i am trying to get my MPG up, as i can definatly tell i'm running rich, (long tube headers supposedly causing it) and just want to verify what sensors are used for fueling.
The obvious to ME (Starting at front of engine):
MAF
MAP
IAT
IAC
Coolant temp
O2 (fronts)
here is my situation. cold engine, its very very very strong. feels like it has MORE horsepower than it should. when it warms up, it runs great still, very very strong, however, not as much as when its warming up. i figure its still in open loop and the sensors aren't talking as of yet. once it goes into closed loop, it seems like it loses a (very small) bit of power. yet still noticable on bottom end (1500-3000 rpms). I have replaced the following on the car trying to get the MPG's up to where i think it should be (25+ on highway).
Air filter was cleaned (its a K&N)
MAF was cleaned 6 months ago, then replaced with a new unit last week (long story on that)
02 sensors were both replaced (FRONT) about 3 months ago
Spark plug wires, MSD
Spark plugs, NGK iridium
I refuse to believe, that the headers and exhaust are causing my problems. my CATS are deleted, but again, that should not cause a low highway MPG. i have a feeling there is a sensor, that is borderline bad, not throwing a code yet, but causing an issue. Looking for your thoughts on this.
BTW only codes showing are P161 (o2 heater for rear (no cats, i don't care)) and P1133 and P1153 front o2 sensor low switch counts...
My car:
02 Trans Am Firehawk LS1 A4, 3.23 gears.
stock engine stock tune (tune validated by GM when they flashed my PCM).
Long tube headers, Corvette 02 sensors (longer wires) full 3 inch exhaust (unknown brand).
i get about 14-16 mpg in town, and 20-22 on highway (70-75 mph).
my question is... What sensors, aid in fuel metering... i am trying to get my MPG up, as i can definatly tell i'm running rich, (long tube headers supposedly causing it) and just want to verify what sensors are used for fueling.
The obvious to ME (Starting at front of engine):
MAF
MAP
IAT
IAC
Coolant temp
O2 (fronts)
here is my situation. cold engine, its very very very strong. feels like it has MORE horsepower than it should. when it warms up, it runs great still, very very strong, however, not as much as when its warming up. i figure its still in open loop and the sensors aren't talking as of yet. once it goes into closed loop, it seems like it loses a (very small) bit of power. yet still noticable on bottom end (1500-3000 rpms). I have replaced the following on the car trying to get the MPG's up to where i think it should be (25+ on highway).
Air filter was cleaned (its a K&N)
MAF was cleaned 6 months ago, then replaced with a new unit last week (long story on that)
02 sensors were both replaced (FRONT) about 3 months ago
Spark plug wires, MSD
Spark plugs, NGK iridium
I refuse to believe, that the headers and exhaust are causing my problems. my CATS are deleted, but again, that should not cause a low highway MPG. i have a feeling there is a sensor, that is borderline bad, not throwing a code yet, but causing an issue. Looking for your thoughts on this.
BTW only codes showing are P161 (o2 heater for rear (no cats, i don't care)) and P1133 and P1153 front o2 sensor low switch counts...
