HELP ???
12-05-2007, 12:36 PM
#1
1st Gear Member
Thread Starter
Join Date: Jul 2007
Location: wyandotte, M.I
Posts: 94
HELP ???
ok i posted these befor and i did wat every one said to do but my car still runs like crap. i got a o/r mid pipe and cat backs put on like 3weeks ago and CEL comes on. i took it to autozone and they said that the air/fule ratio wasnt good. now my question is could it be that i have to get the MIL eliminators so that my car would run the way itshould and to turn off the CEL? could it be makeing the computer make my car run like crap??
12-05-2007, 03:51 PM
#6
6th Gear Member
Join Date: May 2006
Location: Ohio
Posts: 6,448
RE: HELP ???
Just so you know the rear O2s have nothing at all to do with the air/fuel ratio of the engine. They only check to see if the cats are working.
I hear this all the time so I'm going to explain how your engine and sensors work.
Air is drawn in threw the MAF which measures the amount of air coming into the engine. The IAT senses the temp of the incoming air. The TPS tells the computer how far the throttle blade is open. The ECT tells the computer what the engine temp is. Now the computer takes all of this information from all of these sensors and decides what the PW of the injectors should be inorder to get a 14.7:1 air/fuel ratio. Once the air/fuel charge is burned and expelled from the combustion chamber thru the exhaust it passes by the upstream O2 sensors which reads the amount of O2 left in the exhaust gas. The computer compares that reading to its initial reading and adjust the PW of the injectors. Next the air passes by the down stream O2 sensors and reads the amount of O2 left in the exhaust. The computer compares the downstream to the upstream. If the O2 levels in the down stream match or are not within limits of the upstream the computer triggers the check engine light. The cats absorb O2 and use it to burn all the bad crap in the gasses the the cali hippies whine about. The cats need the O2 inorder to do that so if the downstream sensor sees that no O2 is being absorbed by the cat the computer knows that the cat is not working which is why the check engine light comes on.
The rear O2s have nothing at all to do with the function of the engine.
To the OP what code are you getting? You could have an exhaust leak which will throw off the upstream O2s reading and F up your A/F ratio.
I hear this all the time so I'm going to explain how your engine and sensors work.
Air is drawn in threw the MAF which measures the amount of air coming into the engine. The IAT senses the temp of the incoming air. The TPS tells the computer how far the throttle blade is open. The ECT tells the computer what the engine temp is. Now the computer takes all of this information from all of these sensors and decides what the PW of the injectors should be inorder to get a 14.7:1 air/fuel ratio. Once the air/fuel charge is burned and expelled from the combustion chamber thru the exhaust it passes by the upstream O2 sensors which reads the amount of O2 left in the exhaust gas. The computer compares that reading to its initial reading and adjust the PW of the injectors. Next the air passes by the down stream O2 sensors and reads the amount of O2 left in the exhaust. The computer compares the downstream to the upstream. If the O2 levels in the down stream match or are not within limits of the upstream the computer triggers the check engine light. The cats absorb O2 and use it to burn all the bad crap in the gasses the the cali hippies whine about. The cats need the O2 inorder to do that so if the downstream sensor sees that no O2 is being absorbed by the cat the computer knows that the cat is not working which is why the check engine light comes on.
The rear O2s have nothing at all to do with the function of the engine.
To the OP what code are you getting? You could have an exhaust leak which will throw off the upstream O2s reading and F up your A/F ratio.