A word of caution. Do not clear codes on the scangauge while the engine is running. It works MOST of the time but I have seen far too many instances where it leaves the processor in an unknown state which can be a pain to clear. Only clear codes while the engine is stopped and the ECM is otherwise not busy.
Home made MIL eliminators and/or O2 Sensor spacers?
- Thread starter Xcentric
- Start date
BlackICE
GT Owner
bonehead
GT Owner
You're not the only one. 'Burning out' the 02 sensors should trigger a CEL, not eliminate it.
That would certianly poison the 4 sensors but would just set the CEL permanently. Or if reset it would just come back within 3 drive cycles. Besides, the foreward 2 sensors are important for the ECU to auto adjust fuel trims. Running without them long term would eventually lead to the fuel mix trending rich or lean without compensation. Would not recommend this option for long term use.
+1. Was this something that coincidentally happened? Or did you know in advance it would work?
Is lead additive not the same? IDK if that is still sold.
Coincidence - After about 300-500 miles with the FRPP Rear Exit Headers, the CEL came on and stayed. Then, in July, 2007, I went to Miller Motorsports Park in Tooele, Utah, for the combined SAAC32 and SVTOA convention. Since I had no cats, I fueled at the track 3 times with 110 octane leaded gasoline (about 12-14 gallons each time) when tracking the car. After the 2nd fillup, The CEL went out. The Ford Racing trailer was there, and Denis Breitenbach was with them. I asked them about it, and they said that the leaded gas was the culprit. Upon returning home, I purchased new sensors and stored them away. I noticed no change in the performance of the car.
By the way, lead substitute is still available, as I've been using it in my old Mustang for years. I get it at O'Reilly Auto Parts.
BlackICE
GT Owner
That can't be a good thing. I know people who never learn from their mistakes. I tell them their lives are open loop. Blank stare is the typical response.
PL510*Jeff
Well-known member
Spoken like a Floridian…..lots of blank stares during the winter season. Scary isn't it.
SMOKDU
GT Owner
- Dec 17, 2011
- 412
I used to run leaded race gas with my Bigstuff3 and my 02s lasted about 3000 miles. When I ran C16 they would only last 2 weeks. My tune was dead on and in open loop the whole time so I never really needed them unless I wanted to see A/F numbers. Ruining leaded fuel wrecks the 02s and might give false numbers to the ECU causing the wrong A/F to be shared with the ECU .This would turn on a cel light only after the 02 was not reading because of the lead clogging the 02s. The rear 02's just measure the cat efficiency I believe and do not control anything with closed loop in the ECU. The CEL is telling you the exhaust temp after the cat is out of its normal heat range and turns on the CEL light. If your light went off after race gas it might have been a different code that was on or you heated up the 02s enough to fake the ECU in thinking you had cats. Maybe a lean code or misfire code was fixed. just a thought. Using leaded fuel will clog the front 02s that effects the tune. Get a tune and turn off the rear 02s. ? BTW we fixed the bad 02s by running them in our daily drivers for a month with just welding a extra bung in the exhsaust and let them burn clean. But we went though many 02s and we were cheap.
Thx Mark (smokdu)
Ps it this was not long enough the answer to the drive Cycle if anyone want to know is. The car goes into a ready statice and even if the light is turned off it needs to go thru a drive cycle key on and off mode that turns off the ready codes. Our new scanners shows us if someone turned off the light before they want to trade the car so we can see what Code was eliminated. We also do emission testing and there software tells us also if the car has not gone thru its drive cycle . The light can be off and you will fail. Also the ECU will never learn to just turn off lights.
Thx Mark (smokdu)
Ps it this was not long enough the answer to the drive Cycle if anyone want to know is. The car goes into a ready statice and even if the light is turned off it needs to go thru a drive cycle key on and off mode that turns off the ready codes. Our new scanners shows us if someone turned off the light before they want to trade the car so we can see what Code was eliminated. We also do emission testing and there software tells us also if the car has not gone thru its drive cycle . The light can be off and you will fail. Also the ECU will never learn to just turn off lights.
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First, the O2 sensors do not measure temperature. They meassure air/fuel ratio with a wide voltage swing right at the stociometric point.
With the rear O2 sensors turned off, the CEL light will never be set for cats missing. The OBD Emmissions check will show all tests ready except for the cat converter check. Emissions tests allow one NotReady code and still pass. Even in CA. Its an EPA reg. It used to be 2 NR codes but was changed a few years ago. One of the few emissions laws that were changed retroactively to older cars. Visual check is another problem altogether.
With the rear O2 sensors turned off, the CEL light will never be set for cats missing. The OBD Emmissions check will show all tests ready except for the cat converter check. Emissions tests allow one NotReady code and still pass. Even in CA. Its an EPA reg. It used to be 2 NR codes but was changed a few years ago. One of the few emissions laws that were changed retroactively to older cars. Visual check is another problem altogether.
The first time I saw "MIL Eliminators," I thought it was a way to get rid of your mother-in-law.
SMOKDU
GT Owner
- Dec 17, 2011
- 412
I agree. I was just pointing out we can see if the car is ready to test and we can see if someone knows of a problem and just cleared the code. It is worth checking this if you are buying a car so 3 miles down the road the cel light does not come on for a major problem.
DakotaGT
GT Owner
Update: No CEL and no stored codes in 5 or 6 tanks of gas.
The 1st CEL was after about one tank. The 2nd after about two tanks. None since. I did nothing except clear the codes. I'm thinking that no codes in well over 1,000 miles means it's not likely to happen again. We'll see.
It must be closed loop and has learned that I don't give a sh!t. :lol
The 1st CEL was after about one tank. The 2nd after about two tanks. None since. I did nothing except clear the codes. I'm thinking that no codes in well over 1,000 miles means it's not likely to happen again. We'll see.
It must be closed loop and has learned that I don't give a sh!t. :lol