terrible gas milage
03-10-2011, 10:22 PM
#1
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terrible gas milage 2002 formula ls1 pacesetter long tubes ory n ebay muffler and mail order tune by frost. for the past few months i have been makin 18 or less mpg being as nice as i could possibly be to the car and have a 25 mile commute everyday and 18 of it is all highway cruising 70.
it has no codes showing and smells very rich when just parked. it has cut and extendd 02 sensors and im woundering if i should just buy the longer vette ones that are better but just wanted a second opinion thanks.
it has no codes showing and smells very rich when just parked. it has cut and extendd 02 sensors and im woundering if i should just buy the longer vette ones that are better but just wanted a second opinion thanks.
Last edited by SKULL; 03-10-2011 at 10:37 PM.
03-10-2011, 11:52 PM
#2
O2 sensors must not be cut or modified in any way. It's a common mistake because you ruin them. Modified O2 sensor=trash
The O2 sensor has a 1 Volt working range. If you cut the cable and elongate it you are adding resistance (Ω) to the sensor's circuit. Also, the air reference may be disturbed.
So, the millivolts signal the sensor is sending is now wrong. It won't trip DTC codes, but AFR won't be stoich anymore because the added resistance will cause the PCM to see lower millivolts than real. If the air reference of the sensor was blocked or disturbed, the signal may be even worse, leading to very low mileage.
Lower millivolts=lean, so the PCM will enrich the mixture. How much? it depends on how good are the splices of the cables. Bad unions have very high resistance.
You need new sensors. Buy a set of harness extensions, they are like $30 each, that is the correct way to elongate O2 sensors.
The O2 sensor has a 1 Volt working range. If you cut the cable and elongate it you are adding resistance (Ω) to the sensor's circuit. Also, the air reference may be disturbed.
So, the millivolts signal the sensor is sending is now wrong. It won't trip DTC codes, but AFR won't be stoich anymore because the added resistance will cause the PCM to see lower millivolts than real. If the air reference of the sensor was blocked or disturbed, the signal may be even worse, leading to very low mileage.
Lower millivolts=lean, so the PCM will enrich the mixture. How much? it depends on how good are the splices of the cables. Bad unions have very high resistance.
You need new sensors. Buy a set of harness extensions, they are like $30 each, that is the correct way to elongate O2 sensors.
03-11-2011, 01:29 PM
#3
The 02s are the fueling 'boss' at cruise and all warm idle/light throttle conditions. I'd suggest replacing those with the 13111's or some other long-leaded unit to avoid extensions if possible. Sometimes extensions work out, sometimes they cause problems.
03-11-2011, 05:40 PM
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alright ill prolly be buying some vette 02 sensors this weekend along with a borla exhaust from a guy on tech, so hopefull get this thing running right soon.
and frost im tryin to stay on justin(bad6as) to get him back down there asap to get that car finally finished and not take a year to get down there the next time lol
and i was the guy with the glasses when us 3 came down for the tune
and frost im tryin to stay on justin(bad6as) to get him back down there asap to get that car finally finished and not take a year to get down there the next time lol
and i was the guy with the glasses when us 3 came down for the tune