So I replace the sensor with a brand new Denso Universal. I know all the wiring, etc. was done right. I reset the ECU. Everything's good...for about a week. Then the same stupid light comes back on P0133.

I clean the TB, clean all the sensors in the intake manifold, etc. with throttle body cleaner. Then I reset the light because I figure it could have been some other sensor fault that was constantly making the car run a certain way. Noope...light came back on in about a day.

This whole time, my gas mileage is shitty. Like 25-26MPG with 75% highway driving (at 70mph, cruise control set).

I call the sparkplugs.com. They graciously ship me out a new sensor with minimal fuss. Great customer service. I take out my old sensor. Totally char broiled. I go as far as to test and replace a MAP sensor also. I put in my new O2 sensor. It was all good. The car seemed to be running better. The engine light stayed off for a while. TODAY MY FREAKING CEL CAME BACK ON AGAIN FOR P0133!!!!!!!!

WTF?!! I'm gonna give my car a face so I can punch it in the face!!

Anyone have this happen? Anyone have any input? What the freak? I was thinking it may be a faulty FPR or something. Since it's mechanical and the ECU doesnt monitor it. It says on the autozone code sheet that one of the causes may be a fuel system running too rich or too lean.

I figure this to mean that if the fuel system was running too much either way, the O2 sensor would just appear to have slow response. Which is why the FPR makes sense...since the fuel injectors may not be able to lean out enough with the FPR raising fuel pressure.

But I'm not sure of this theory.

Things you should know if you're trying to help:

I have replaced my spark plugs, wires and distributor with OEM or OEM spec replacements.

The car came with I/H/E. The header is an OBX header. The intake/exhaust are probably some Ebay kung fu racing combo. The air filter is clean. The header puts the O2 at factory position. The exhaust is being replaced with a world sport soon.

The distributor requires me to put it almost all the way advanced for it to be in time. I'm guessing a stretched or skipped timing belt is the culprit. I will replace the T belt/water pump when Illinois is not a frozen wasteland.

Someone told me that there was some TSB on this or something. What would the TSB be under? They said something about the ECU's driver being too sensitive.

Here are pics of my O2 sensor (The 1st denso universal I put in). It only had about 2-3k miles on it. CHAR BROILED!!!!!

The car has 106k on it. Doesn't burn oil. Doesn't burn/lose coolant. Exhaust smells pretty normal. Maybe a little rich...but not really. I might take it to my friend at the Honda stealership. Have him get the fuel table information...but I'm not sure what the freak I should be looking for. It's obviously running rich. I have no clue why.

Modified by B serious at 4:36 PM 3/3/2008

"Give me the ball, alligator"

I think so too. Barbecued O2 like that seems like there is fuel burning inside the manifold, as well as poisoning the sensor which is usually how they get slow. LOL at the face thing, too.

"A Bugatti Veyron is so fast, that you could let a McLaren F1 accelerate to 120 mph, and then start the Bugatti, the Veyron would beat the McLaren to 200 mph"

Manifold pressure should not be confused with the volume of air that a turbo can flow.

Yeah...I had that theory as well. I'll probably just buy the stupid T belt and water pump and do it in april. My S2000 comes out of storage in april, so I'll have another car to drive for a day if need be. I wanted to do the clutch as well....so maybe i'll just take the entire engine/trans out of the car. That whole operation might take a whole day...or day and a half depending on if I work alone or not.

"Give me the ball, alligator"

I have the same problem right now. 3 o2 sensors later and its still the same shit. Barbecued o2=(. The code first appeared when I got a del sol edelbrock header installed on my em1, so fitment wasn't right. After that, code didn't stopped coming even though i went back to my stock header.

It's the most annoying shit ever especially when don't have the shit to work on ur own car. Sometimes I just drive my car with the [freak]ing CEL on. I wish my car had a face too.

I think I'm gonna get a new ecu from somewhere, although my car is still warrantied through honda. The thing that I'm not sure about is if I need to get my car to full stock set up before going to honda to get the warranty through the bulletin. What I have on the car right now that is not stock is short ram and aftermarket exhaust catback.

So how's it goin with ur em1? Got any updates?

Modified by Jawlz at 9:46 PM 5/9/2008

If your fuel pressure regulator was the culprit, it shouldn't affect the O2 sensors ability to switch (timewise). I would rule that out unless your having other fuel related problems.

Whats going on with your timing? You should check that before you do anything else. Your going to have a more difficult time pin pointing problems if the engine isn't timed corectly. Start there before you put anymore money into it.

I guess I should have updated...but the thread wasn't going anywhere.

My gas mileage was a little wack before.

I figured the fuel pressure regulator's diaphragm was worn or torn or something so the car was ALWAYS running rich no matter how much the O2 sensor told the ECU to run lean. So maybe the ECU did issue a lean command but didn't see anything change at the O2 sensor. Since the FPR is unregulated by the ECU, the O2 may have been the ECU's #1 suspect. The O2 also looked very fouled in a short amount of time. I figured it had been fuel fouled.

I hadn't really thrown any money at the car. That's not how I roll.

The reason I thought the timing was off because the car kinda gurgles a little bit..it has IHE. I changed the timing belt (it was due anyway: 107k miles) and am DAMN sure the timing is right now. The gurgle is still there....but I've heard other people who have the same header complaining about a gurgle as well. The header is of a weird design..so I figure the gurgling could def. be because of the header.

Anyway....I got a FPR at a junkyard for like $1 or something. It was probably free with my $5 motor mount replacement lol. The gas mileage went WAY up as soon as I changed the FPR. The CEL is still on but I haven't bothered resetting the ECU yet. Maybe I'll have my friend at Honda reset the light...or I'll just unplug the ECU fuse. I'm too lazy to reset my stereo.

So the CEL is still tanning my face at every drive...but I dont really care. The gas mileage is now in the 30s range and that's all I really wanted. When emissions comes around, I'll either try resetting the light (it typically stays off for a few days) or change ECUs or something else.

The header may also have a leak in it...which I'll definately assume will cause a "lazy O2" CEL to come on. It's been proven to do so ...so I feel it's a safe assumption. Again...I'll fix it when I get around to it.

As far as I'm concerened, as long as the gas mileage is in the 30s....I dont care.

"Give me the ball, alligator"

have no idea why im getting this stupid code over and over and over again... did the FPR help?