o2 Sensor Problem? PLZ HELP

[Generation1JeY]

Ok i'm not sure what is going on with my car, but i'm leaning towards a messed up o2 sensor.

Alright a couple weeks ago i installed my full 3" rnr o2 eliminator exhaust. Before i had the exhaust on there i had my mbc set at 15 psi and everything was fine, i had zero fuel-cut, i had no complaints whatsoever ok. Then i install my exhaust, after i installed my exhaust i noticed increase in power, throttle response, spool-up time, all that, unfortionately it made me creep a little bit so i had to turn my boost down so it would stay at 15/16psi.

Ok so everything is good, then maybe a week later (a few days ago) my idle started to get messed up, it would fluctuate and pulse from 400-1200RPM. Also my car would keep dying and bogging, say i was driving in third gear and i saw a red light ahead, if i put the clutch in and just let the rpms fall, they would fall all the way to 400 and the car would eventually die. That didnt happen ALL the time, but it happened enough times to get very annoying. Also i got my CEL, so i reset my ecu, and it went away then it came back the next day, then it went away again. With the idle and the cel i've always hear its an o2 sensor.

Then the biggest problem of all i noticed a few days ago as well. My cars power seriously just DIES at about 4000-4500RPM. Like my turbo will spool up all fine, then when it spools up all the way and i start to hit my full power band, my car will just stop accelerating and it feels kinda like i'm runnin a t-25 turbo cause its like the turbo just drops off. Also i keep hitting SEROIUS fuel cut, i keep checking my boost gauge and i'm only at 15 psi and i've always ran that and have zero problems with fuel cut. but seriously i'l try and do some 2nd gear pulls and after the turbo spools all the way my car just stops accelerating and just revs and makes very bad noises and sounds like its about to just explode. I'm wondering would the o2 sensor be responsible for all this?

Also i'm using a ridiculous amount of gas when i do hard pulls so i must be running extremely rich cause maybe the computer is getting the wrong signals from the o2 sensor or something?

Any help is appreciated, i'm just hoping its my o2 sensor so i can just go pick up another one i hope theres nothing seriously wrong with my baby.

Thx

 

[flytalon93]

Its hard to tell exactly whats wrong with your car, but it is definitely pulling your timing. Too bad you weren't able to pull the code from the ECU before you cleared it. I just don't see how bolting on an exhaust would mess up your O2 sensor on a 1g. When was the last time it was replaced? As far as your creep, did you port out the O2 housing and manifold yet?

Edit: I just reread your post and noticed you got the O2 elimimator. Where exactly is the O2 now? I don't have an O2 eliminator so I wouldn't know.

 

[Generation1JeY]

the o2 sensor is in the exact same place it was before on the stock o2 housing, its right on the beginning of the downpipe.

The creep issue is already resolved i got it steady at 15 psi so i'm all good with that. The only thing i'm trying to understand is whats wrong with my power and my idle and why the car is bogging and whats with the CEL.

Also i noticed right when i got off the freeway last night that my car almost stalled, and u know how when u do all the check lights come on, well like the car stalled but then it came back up, but the lights stayed on. And they keep staying on, the engine coolant light, the brake light, and the battery light stay on ALL THE TIME, even when i reset the ecu they still stay on whether my lights are on or anything. Even when the parking brake is all the way down the light is still on so there is something seriously wrong with some sort of electrical device or something.

Any more help would be great.

 

[flytalon93]

Pull the ECU and check for cap leakage.

 

[psychlow]

I've got $10 on a boost leak.

Pressurize your system per instructions on the VFAQ and cap your system back up wherever it leaks.

 

[Generation1JeY]

I've got $10 on a boost leak.

Pressurize your system per instructions on the VFAQ and cap your system back up wherever it leaks.

u can paypal me the money dude cause i dont see how it could be a boost leak. Its at moderately high rpms when my power just sorta drops off, i'm still maintaining full boost but i'm just not accelerating as fast as i should and i keep hitting fuel cut.

I mean does anyone know of something that could just change ur fuel cut all of a sudden? Something that makes ur CEL turn on and off, something that makes random lights turn on on ur dash, something that messes up ur idle and makes u bog and stall, something that kils all ur top end power?

Suddenly the leaky caps sound like the winning culprit. I'll be checking those tommorrow and i'll get back to u, if it is those and my ecu is toast i really am going to kill myself, because i have the replacement caps sitting right here on my desk i'm just too lazy too change them, that and also i'm not the best soldnerer. is that even a word?

 

[psychlow]

u can paypal me the money dude cause i dont see how it could be a boost leak. Its at moderately high rpms when my power just sorta drops off, i'm still maintaining full boost but i'm just not accelerating as fast as i should and i keep hitting fuel cut.

Exactly. Now, I'll explain why I said that:

Also i'm using a ridiculous amount of gas when i do hard pulls so i must be running extremely rich ...

A boost leak will cause this. Why? The MAF is metering X air as it enters the turbo. Then it makes its way up the intake pipe and leaks some amount of air (Y) off. Thus, you actually get X-Y air to the engine, which means you run pig rich because the ECU was expecting more air.

Then the biggest problem of all i noticed a few days ago as well. My cars power seriously just DIES at about 4000-4500RPM.

The above causes this. The faster you spin that turbo, the more air your MAF is reading, and the more air you're leaking into your engine compartment. You become pig rich, and your car becomes slow.

Now, what is fuel cut caused by?

Fuel cut is when the ECU is reading a certain amount of airflow that the ECU wouldn't normally see at a certain barometric pressure and a certain temperature.

The reason FC exists is in case your wastegate get stuck shut, and suddenly you get 20PSI of air in at WOT. This would explode your engine. Now, the ECU doesn't have any way of seeing there's x psi of air in the system. So, instead it relies on MAF data. You only see 15PSI on your boost gauge because that's all that's making it to the engine. But the MAF is reading much, much more air coming in that leaks out of the system.

Another reason I believe it is a boost leak is because you mentioned that your turbo was creeping. When that happens, it tends to break loose seals that previously held tight at 15PSI, but can't hold at 17PSI.

All in all, you end up with extremely poor gas mileage, a rough running motor with fuel cut at WOT, and a check engine light because your poor O2 sensor can't figure out what's going on and why the A/F is so rich.

I can tell you for a fact, with 100% certainty, that the O2 sensor is not your problem in this situation. O2 sensors do not affect WOT fuel maps. Your ECU goes into open loop operation above a certain throttle percentage, meaning that it relies on its own internal maps and doesn't even reference the O2 sensor.

If you DO have a bad O2 sensor, it may, in fact, affect your idling woes. But, check for leaks first. If your leak is bad enough, at engine vacuum you'll be drawing unmetered air into the engine and running lean.

 

[Generation1JeY]

thx psychlow for helping me out i appreciate it, when this rain stops boost leak will be the first thing i check, but i also have an update on how ####ed up my car is.

On the way to school this morning my car was just how it was yesterday when i told u guys about how the power was gone and all that. Well i drive my car home afterschool, and every single thing that could be wrong is wrong. When i start it up my starter makes a weird sound like it doesnt have much power, also everything in my car has little to no power, my windshield wipers on the highest setting are barely moving, my ac doesnt work, my blinkers blink really fast, my headlights dont work, the automatic seatbelts move extremely slow, and i every single engine light is randomly going on and off, my antilock brake light keeps coming on and off, cel on and off, radiator, brake, oil, battery, everything.

Now to the engine, my car is idling at about 2500RPMS, and as of right now my car is undrivable, on the way home i could barely get the car to acceleterate, example: i'll be sitting at the light with it in first gear and my foot on the clutch, its idling at about 2500RPMS, the light turns green, i slowly let off the clutch and give it gas and all the engine does is bog. It can barely leave and even when i get it moving its just going puttt putt puttt and barely moving.

As of right now i can think of maybe 2 reason why this is all happening:
1. The rain, i dont know if some water got inside the engine bay and just fried some electrical device or something but my car started acting like this right when it started raining a few days ago. And i'm in san diego so it never rains here, kinda coincidence that it messes up right when it starts raining.

2. Like someone stated earlier my caps on my ecu are just leaking more and more and ruining my ECU. This one seems more logical to me because my electrical system is completely screwed also and my engine lights are all over the place and my engines performance is messed up so wouldnt the ECU be the only thing that can mess up both?

If i'm wrong or anyone has any other suggestions plz let me know. Its pooring down outside right now so all i can do is sit inside my house thinking of what can possibly be wrong with it, i cant work on it or check anything so u guys gotta help me out here. Whe it does stop raining i'll go pull the ecu and check for the leaky caps, i'll check my battery and make sure nothings wrong with it, and i'll check for boost leaks.

Until then though anyone have anymore ideas?

 

[Generation1JeY]

ok another update my battery is completely dead and my car wont turn over at all

 

[boostedinaz]

I had my PS pump leak on my FMIC pipping on my Laser and it would blow off pipes all the time. Some times it would just leak and when it did this it would do excatly what you are describing, like it has already been said before. Pressure test the car and get back to us. Once that has been ruled out, doubt it, then we can go from there.

The other thing I can see happening is that if you battery was on its last leg ti will not create enough voltage to fire the ignition. With the same problems I had above the ALT was killed due to the PS leaking. When it did that it wouldnt charge the battey and I was only seeing 12.5 volts. If I made a WOT pull it would start to mis becasue the ignition system doesnt work well unless it has enough power to due so. I would hit 5k and the car would just start to mis and not pull.

Here is you plan of attack. Take the ALT and battery to get tested and charged. Pressure test the system and make sure you have NO leaks. Once those are done take it for a spin and see what you got. I have a feeling it will be fixed.

 

[DSMeclipse4G63]

Its hard to tell exactly whats wrong with your car, but it is definitely pulling your timing. Too bad you weren't able to pull the code from the ECU before you cleared it. I just don't see how bolting on an exhaust would mess up your O2 sensor on a 1g. When was the last time it was replaced? As far as your creep, did you port out the O2 housing and manifold yet?

Edit: I just reread your post and noticed you got the O2 elimimator. Where exactly is the O2 now? I don't have an O2 eliminator so I wouldn't know.

damaged or contaminated O2 happened to me. But doesnt have the same signs your are stating gen1g.
Andrew

 

[Generation1JeY]

ok today i pulled my ecu and checked it out for the leaky caps. The big one next to the small one is leaking like a bi***, the other two seem to be fine, but that one big one leaked all over and a couple other litle metal parts aound it are black. If u dont look at it very hard it seems very doubtful that something that tiny would completely make the ecu malfunction, but i guess something that small can mess it up that much.

I'm guessing if the capacitor fluid leaked on the board and its messed up as mine is its not fixable so ill have to buy a new one.

But i'm still curious as to how my batery died from the messed up ecu? Can having a broken ecu make ur battery die or atleast make it seem like ur battery is dead by not turning the engine over at all?

I'm gonna get s'more help on this issue so that i can figure out exactly whats wrong so i dont keep letting the problem go, but any help from u guys is greatly appreciated if u have ever been on the same boat i am on right now.

 

[psychlow]

Is your power steering pump leaking at all? Has your alternator gotten wet?

If it is, and is leaking on your alternator, that could be what caused your ECU caps to leak. There is a voltage regulator in your alternator that makes certain the alternator doesn't produce too much voltage. If it gets leaked on, it'll fail, allowing voltage spikes to affect the ECU and fry it.

It sounds like a combination of things may have occurred, as in maybe the above happened, and now your alternator is dying completely.

Just a theory, though. If you still experience problems after you get a new ECU, definitely pressure test the system and check for leaks. If you still have electrical problems, do a charging system test and check your alternator's output voltage to make sure you don't fry a new ECU.