How TO: CEL/MIL Eliminator!
- Thread starter acidbug
- Start date
I just tried this on my 1.8L ES and instead of fixing it I've thrown a P1135 CEL. Which, from what I can understand from this thread, means that by splicing the heater wires together has created a low voltage situation in which the ECU thinks there's something physically wrong with the O2 sensor. I'm using the same 1M resistor, but I'm using a 50V (still a 1uf) electrolyitic cap, is anyone using a metal-film 250V cap instead and having success? they're both 1uf, but the metal film was 250V, and +/- 10% variance and the electrolytic was 20%
ok, question.. I just bought my spicy orange. I dont have a header on my but I did throw a code of the o2 sensor warm up circuit. Can I disconnect it and the light will eventually go off if I dont use the obdII scanner to erase it or should I just go with the non fouler setup or do the resistor setup and this is for the 2nd o2 sensor instead of the first (correct me if wrong).. PLEASE HELP!!!!!!!!
i have to say the non-fouler work for my car with the header, but after i boostd it it did not work. i had 2days to get it fixed before the emissions suspended my lic.. so i did the the how to stated and i passed. have to say thanks acidbag for the how-to. wilson
beerbucket
Member
Hi folks,
I've just had the MIL come on in my 99 Miata, and have read this thread with interest. I have a few questions, some info and a suggestion...
Q1. Is it legal to put your car through emissions with this installed?
I borrowed my friends OBDII scanner to get the code (usual, P0421) and was reading the manual with interest. It has a good description of how the O2 sensors figure out how the catalytic converter is performing:
" The computer checks the efficiency of the catalytic converter by monitoring the two oxygen sensors that are utilized in the system, one before (upstream) and the other located after (downstream) the converter. If the catalytic converter loses its ability to store oxygen, the downstream oxygen sensor signal voltage waveform becomes almost identical to the upstream oxygen sensor signal, and the monitor will fail the test."
So, in other words.. the computer compares upstream voltage to downstream voltage, and if downstream isn't smaller than upstream, the MIL comes on.
It seems to me that the mod here just attenuates the downstream voltage enough to make the computer think that the cataytic converter has done its job well.
Q2. Has anyone tried this mod without the cap?
A 1M resistor will surely attenuate the signal enough on its own! What could the cap be for? If nobody else has tried it, I will. It would be a much nicer mod, too: an inline resistor, all heatshrinked up.
Finally, just so I'm sure to get this right:
Q3. It's the O2 sensor *after* the catalyst (downstream) that gets the mod, right?
Any comments are appreciated!
I've just had the MIL come on in my 99 Miata, and have read this thread with interest. I have a few questions, some info and a suggestion...
Q1. Is it legal to put your car through emissions with this installed?
I borrowed my friends OBDII scanner to get the code (usual, P0421) and was reading the manual with interest. It has a good description of how the O2 sensors figure out how the catalytic converter is performing:
" The computer checks the efficiency of the catalytic converter by monitoring the two oxygen sensors that are utilized in the system, one before (upstream) and the other located after (downstream) the converter. If the catalytic converter loses its ability to store oxygen, the downstream oxygen sensor signal voltage waveform becomes almost identical to the upstream oxygen sensor signal, and the monitor will fail the test."
So, in other words.. the computer compares upstream voltage to downstream voltage, and if downstream isn't smaller than upstream, the MIL comes on.
It seems to me that the mod here just attenuates the downstream voltage enough to make the computer think that the cataytic converter has done its job well.
Q2. Has anyone tried this mod without the cap?
A 1M resistor will surely attenuate the signal enough on its own! What could the cap be for? If nobody else has tried it, I will. It would be a much nicer mod, too: an inline resistor, all heatshrinked up.
Finally, just so I'm sure to get this right:
Q3. It's the O2 sensor *after* the catalyst (downstream) that gets the mod, right?
Any comments are appreciated!
Anyways...this thread is much better, its the one that I did... Click Here
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- 2003 Mazdaspeed Protege
Will this work if you run an electric exhaust cut-out right before the 2nd O2 sensor. I'm in the process of having someone make one for me and I was wondering what I needed to do. Thanks.
-Rob
-Rob
Help me please how exactly do you connect the capacitor
I have just one question. Maybe im just retarded and don't know how to follow instructions but does it matter what kind of 1uF capicitor to use? i got one of those round ones and not the flat ones as shown in a pic later on in this thread.
Also what do you mean by "Grap your 1uF capactiro and solder it into the wire that you unsheathed/exposed & than solder it on the connector side as show on the Pic!" I cant see anything in the pic. How exactly do i connect the capacitor????? What i really don't understand is where do i solder it on the "connector side?"
I did the resistor part already because those instructions are very clear but i still get a CEL. I wasn't lucky enough as another poster that just did this and "it worked"
Help me please.
Never mind.... Where was the schematic yesterday when i tried this mod??? Im fricken Retarded
I have just one question. Maybe im just retarded and don't know how to follow instructions but does it matter what kind of 1uF capicitor to use? i got one of those round ones and not the flat ones as shown in a pic later on in this thread.
Also what do you mean by "Grap your 1uF capactiro and solder it into the wire that you unsheathed/exposed & than solder it on the connector side as show on the Pic!" I cant see anything in the pic. How exactly do i connect the capacitor????? What i really don't understand is where do i solder it on the "connector side?"
I did the resistor part already because those instructions are very clear but i still get a CEL. I wasn't lucky enough as another poster that just did this and "it worked"
Help me please.
acidbbg said:
Never mind.... Where was the schematic yesterday when i tried this mod??? Im fricken Retarded
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- 92 & 16 Meyatas
glad you figured it out! i did this mod 2 yrs ago, no problems!!
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- ‘19 CX-5 GTR Tu
Wow..I am suprised to see this thread still going strong after many years...Glad to see it has saved many people's a$$'s.
I wonder if this trick will work for the MSP3/6 guys..
The only car i tested this trick on was the 2.0L mazda engine.
Maybe i will try the trick out when i upgrade the exhaust but than again..the msp3/6's use a wideband o2..
-C
I wonder if this trick will work for the MSP3/6 guys..
The only car i tested this trick on was the 2.0L mazda engine.
Maybe i will try the trick out when i upgrade the exhaust but than again..the msp3/6's use a wideband o2..
-C
Darn CEL just won't stop
Well i did everything as stated in the How-to and my CEL still comes on. but atleast it took 60Miles instead of 25Miles to come back on. Does it matter what type of capacitor used? I used the electrolytic Capacitor but in another post i noticed they used a different type of capacitor. I also figured maybe it's an exhaust leak so i changed all the piping under my car and re-welded all the welds though i haven't reset the computer since i did the CEL eliminator.
Capacitor????
I took three classes in electronics so i know that my soldering is ok and i also tested for continuity and everything checks out.
Well i did everything as stated in the How-to and my CEL still comes on. but atleast it took 60Miles instead of 25Miles to come back on. Does it matter what type of capacitor used? I used the electrolytic Capacitor but in another post i noticed they used a different type of capacitor. I also figured maybe it's an exhaust leak so i changed all the piping under my car and re-welded all the welds though i haven't reset the computer since i did the CEL eliminator.
Capacitor????
I took three classes in electronics so i know that my soldering is ok and i also tested for continuity and everything checks out.
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- 92 & 16 Meyatas
i did the same mod almost 3 yrs ago, no issues, works like a charm? maybe recheck everything?(shrug)
Couldn't get this to work on my 1.8L. I eventually just gave up and made a non-fouler fix. Been over 10k miles on it with no CEL.
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- 92 & 16 Meyatas
ya, the non fouler is a great mechanical fix for many!!
I have been reading all of the post about the MIL to keep the CEL from coming in. It seems all of the post refer to the "protege". I have a 1999 626 and my wiring colors on the 2nd O2 sensor are, grey, white, white, and black. The is only one Cat. Will the same method work on my car. If so how which wire do I hook the resistor and capacitor to. I just need to get an inspection sticker.
