pbook4g5

Yes I meant downstream O2 sensors.

I did some reading to confirm and I learned something new. Just a Cat checker. Awesome. Explains the price difference, too.

BukvaMan

It was posted a while ago by Turbonut...


Second O2 sensor and STFT (long)
What is the purpose of the post cat Oxygen sensor?

Catalyst efficiency monitor?

That's only a portion of its function

REAR FUEL TRIM

a.. The Post-cat O2S has been used since 1988 to control fuel trim (to
some extent)
a.. Toyota and Saab
b.. Used to fine-tune the A/F ratio to maximize catalyst efficiency
c.. Will also compensate for a degraded Catalyst
d.. Every manufacture today uses the rear O2S to trim fuel today


The post cat O2S is a fuel control input. Toyota and Saab have used the
post-cat O2 to control the fuel trim since 1988; Before OBD-II. This sensor is used to fine-tune the air-fuel ratio to maximize catalyst efficiency. It can also adjust the air fuel ratio to compensate for a degraded Catalyst. If you were to measure the actual amount of time the post-cat O2 is used during the running of the catalyst monitor (maybe once per trip) and compare that to the amount of time the post-cat O2 is used fine tune the air-fuel ratio (almost always in closed loop), you will see that this sensors major function is fuel control. Every vehicle manufacture today uses the rear O2S for fuel correction; even if it is undocumented.

pbook4g5

OK, so I guess I was correct in my thinking before hand. Back and forth. Its on the internet so I bet both things are right...

bauermd

iTrader: (1)

GREAT information to know... I got into a little argument today when ordering the oxygen sensor at autozone. The Denso one they wanted to sell me didnt even reach the connector(it said on their computer it was for front downstream) but they continued to try and sell it to me. So I took them to the car and tried to show them. After this I just ordered the ONLY one out of almost 25 in their system for my year, that said "rear downstream". It was 79.99 and is a bosch. It was really odd because today my engine light was off the entire day and the car ran like a dream. I even had the A/C on full blast in stop and go traffic. It seems as the problem is more intermittent now that the weather is cooling down. I pulled the code today and it was P0137. Circuit Low Voltage Bank 1 Sensor 2. I have to wait until the 18th to receive this sensor as it was a "special order" item. I most likely will have to jack the car up and attack this from underneath because it will destroy my knuckles trying it from the engine bay.

I always thought the downstream didnt have any effect on fuel trim, but Turbonut has a pretty good article I see.

Again, thanks EVERYONE for their input and I will post when the new sensor is installed!

screaminz28

iTrader: (1)

I agree it may be used for some SLIGHT modification to fuel trim, but you can disable the secondary o2s in Hondata (I just did mine) and closed loop still works. If you disable the primary, it will run open loop all the time.

I disabled my secondary o2s just to eliminate the code because I've had one for a circuit low voltage, then catalyst efficiency, then it didn't see it at all. In none of those instances did it affect driveability.

bauermd

iTrader: (1)

Yea when you tune out your secondary O2s your ecu is no longer taking input from that sensor. That is a little different from lets say, pulling it out and just not using it. If that makes any sense.

I had my downstreams in my mustang tuned out.

The only reason I am pointing my problems to my downstream O2 is because that is the ONLY code my car is throwing right now. When the engine light goes off, the car runs completely fine. So they have to be related... Car runs 100% fine when the light is not on. The second the light comes on, back to running like a pile of expired dog shit.

bauermd

iTrader: (1)

New O2 showed up this morning. I will be letting the car cool off and attempting to gain access to it in order to change it.

My question is, can you clean O2 sensors? I have done some searching and around 3 out of ever 4th thing I bring up, they state you just submerge the sensor into gasoline and let sit for a few hours and then let dry.

This does not sound safe to me, but I thought maybe I would give it a try on the bad one before I replace. Just to see what happens. Any thoughts?

bauermd

iTrader: (1)

So, I replaced the rear downstream this morning. Funny thing was the old one was loose when I was trying to take it out. I just took it out with my hand.... anyway here is the side-by-side of the two. It is definitely seen better days but I do not know what a "dirty" O2 sensor looks like.



Appears I am running a bit rich?

bauermd

iTrader: (1)

I have came to the conclusion that I am f**ked.
**No engine codes / Car starts completely fine / Idles completely fine**
Just after 15-20 minutes of driving, when hitting the throttle at ANY rpm, it bogs down for a moment, then slowly starts to accelerate. I can feel a slight surge around 3k rpm kind of like its getting the right amount of fuel.

Will ONLY happen when the car is warmed up and driving for a while.

Things ive changed :
Spark Plugs
Timing belt kit
Oil pump / seal
Tranny fluid
rear downstream O2 (got rid of CEL)

Any other suggestions before it goes over a cliff?

BukvaMan

Give it some time for the ecu to adjust to the new sensors. I hope you replaced them both. Mine took 2-3 days from being worse then ever before to where i couldnt recognise my car "good".

I have complained about this for years (same exact problem you describe) and i finally dont have to anymore.

mzilvar

iTrader: (3)

have you tried resetting the ECM by doing the battery disconnect? Leave it off for like 10 minutes and then when it's reconnected let the car idle with all the accessories off for like 10 minutes

pbook4g5

MAP sensor. Change it. Someone mentioned it in this thread, and while if it were bad it should throw a code, maybe its just on the edge of being lazy (I don't know if thats possible).

But, seeing as your this far in, thats one of the only things left. This is a 6 speed, right?

EDIT: I see its an automatic, so there goes my theory of the master cylinder losing pressure under certain situations.

Hmmmm.... did you ever replace the APP?

FamilyGuy

It may not. Mine were seized too and took me nearly an hour to get one bolt out, little by little, with a breaker bar. The f*cker fought me the whole way out. Both front calipers were seized on my car. Acutech fixed it for me (local shop).


OP - maybe this will help with your lack of power issue? - https://acurazine.com/forums/3g-tl-2004-2008-93/those-lack-power-surging-hot-weather-859713/

v8eatr

When you put it in manual mode when its doing it and your taking off from a stop does the gear indicator say 1?

bauermd

iTrader: (1)

So a little update for everyone. I have reset the ECU by disconnecting battery multiple times, and went ahead and did it again for probably the 15th time or so yesterday evening. Then it hit me...FamilyGuy mentioned the battery may be the culprit. The battery is a Duralast Gold purchased brand new from AutoZone in this past December so it has less than 10 months on it. I remember the battery was giving me trouble a few months ago and it died after the car sat for 2 days but never gave me any trouble after that.

I read the attached link and he mentioned my symptoms and how the battery is most likely the case if I have no related CELs and so fourth. This all made sense after reading that post and how to the car will only do it after sitting in traffic or turning on the A/C.

So I just said to my self "Well, I've done just about everything else, why not try this". I went to Sears (Which turned out to be the WORST experience ever) and purchased a new DieHard Platinum from them for the sale price of 169.99$. Mind you the car was doing this loss of power thing the entire way to Sears. After purchasing a 10mm craftsman wrench from them as well because they did not want to lend me one, nor did i want to pay 25$ for someone to undo 2 tiny bolts and waste 5 minutes of their lives at my expense, I replaced the Duralast with the new one. The new battery is MUCH smaller in size, so it was an odd fit for the battery tie-down but I got it to work. The problem went away instantly. I did not want to rely on it being away for good because the battery was cold and just came off the shelf, but I have driven the car 200 miles since with no issues. A/C on, 90 degrees today and was stuck in a 6 mile backup and the car ran completely fine.

Never in my life would I of pointed out a battery for being the culprit here, but like i've mentioned multiple times I am always learning as with the rest of us.

Thanks everyone for their inputs on this issue, and now i Just have to get my car to stop wobbling when hitting the brakes!!

bauermd

iTrader: (1)

aaaaaang the problem is back after a little over a week. No engine lights again. On the bright side I know a wonderful cliff near by that I could accidentally leave it in drive when I get out at..

Also, just got 2 brand new michelin pilot super sports installed for 150$ out the door because my front left blew out going 70 after hitting a road construction bump with no warning signs or anything. Good thing the rim was fine, and I didn't damage the pressure sensor either. Allstate covered the tow too.

pbook4g5

Did you ever change the MAP sensor?

BukvaMan

Do me a favor, go to your fusebox under the hood and unplug any fuse that is VSA related and then plug them back in. Im just curious how your car will behave afterwards...

nfnsquared

Just to rule it out, I'd get the battery tested and also check the connections to make sure they are tight.

Maybe you have a parasitic draw that's killing your batteries?

JustinZ

did you ever get around to replacing the APP sensor?

bauermd

iTrader: (1)

The problem is now worse then ever... Battery is only a week old so I will get it tested along with the alternator. No engine lights and no hard starts or anything. It is bogging down really bad now to where I'm scared to merge into the interstate because it doesn't want to pick up speed barely at all. I have to completely floor it. The entire sound of the engine and exhaust sound changed as well. Wish someone was close enough to see and feel it first hand.

pbook4g5

Are you going to respond to any of the questions we've asked?

Has the APP sensor been changed yet? MAP sensor?

We can only help if you provide us with the answers we've requested... otherwise, we can't help.

bauermd

iTrader: (1)

No, the APP and MAP sensors have not been changed. I have read many forums regarding these and they all seem to have thrown a CEL. I mean I can go ahead and fork over the money for them both just to "test" my luck but so far my luck isn't the greatest. The problem is more intermittent now as it comes and goes multiple times during the same trip. I really do appreciate all of the help though.

Yikes

Hmmm, an odd problem indeed.

I wonder about your timing. After your reset your ECU and changed your battery, it seemed fine. However, your ECU is capable of retarding timing.

You said the problem was there before you got your t-belt changed. I wonder if your timing is off a tooth or two and the tech just slapped a new belt on it without ensuring that everything was a-okay. It may not sound like much, but being off by one tooth will cause a lot of problems.

Don't throw anymore money at the car to replace sensors that probably aren't even bad.

nfnsquared

If it was off a tooth, it wouldn't be intermittent....

pbook4g5

Have you hooked up an OBD II reader to it to monitor short term and long term fuel trims and monitor some real time data?

For the price of the APP and Map sensors, I don't think you'd be much in the hole if they didn't work.

And FWIW, I've heard of many people who have noticeable differences after changing the APP with no CELs prior, so.... yeah. I don't know.

bauermd

iTrader: (1)

https://www.youtube.com/watch?v=eySF...ature=youtu.be

I am trying to upload a video.. the car will normally go really smooth through the RPMS, the RPMs kind of hesitate and the car has almost zero acceleration when the problem is happening. Kind of hard to hear but the exhaust is ALOT deeper when the problem is accuring and almost bogs down like 50-100 RPM at the touch of the throttle.

I will most likely start looking into replacing the APP and MAP as-well. Just is bizarre some days the problem is EXTREMELY bad like the car almost doesnt want to move and some days is 100% fine.

BukvaMan

If you dont mind please just remove the Vsa fuses temporarly under the hood. I believe its a 30 and 40 amp. It will reset it... Im just curious if it will do anything.

bauermd

iTrader: (1)

I will try that today. Just a note, I have never had any problems with the VSA module or the lights coming on or anything but I'm willing to try anything at this point.

BukvaMan

The VSA modulator has the ability to cut power if needed... If something is wrong with it then it could cause a lot of issues.

Just give it a try... Unplug all VSA related fuses and the plug them back in...

You might be in for a surprise ...

bauermd

iTrader: (1)

I understand that but why would the modulator only do it when it wants to? The car runs fine some days like there was never any problem and some days it acts like it has a 1.1L lawnmower engine.

Ill try and locate the fuses. Should I have the keys in or on or car running or anything to do this? Or just open hood and pull and replace?

pbook4g5

I think you need to take a look at the throttle cable hooked up to the APP. I bet there is some slack in it, which would cause the issue(s) you seem to be having. Pull the cover off and look at it and see if the cable is tight.

bauermd

iTrader: (1)

My thought is if it was a slack throttle cable the condition would be static as in it doesn't change. The problem doesn't happen all the time which is why I haven't taken a look at some things that I would have normally. One being the throttle cable.

BukvaMan

With the car off, just pull them out for couple of seconds and then back in...heat could generate more resistance in the wire and could be creating partial loose connection and because of that mess with the ecu ...

BukvaMan

I think im the only guy who knows exactly what you're hoing trough...
Mine is fixed! Ive been telling you about the downstream 02 sensor and it did help in my case but the more i look at it its pointing me to the VSA Modulator.

Whenever that problem appears I take out those fuses and plug them back in and it goes away.

The difference is that the car feels so much lighter. Well because of that increases low end power. Another reason why i think something is up with it is that whenever the car is warm and im braking to a stop my rpms dip so much that car almost stalls out. ( not extreme but still very annoying). After fuses out and back in, it doesnt happen at all.

Go figure.....

bauermd

iTrader: (1)

What fuses are they? My RPMs do the same thing.. not REAL bad but they do drop under like 500 and it jumps back up everytime I stop.

BukvaMan

if you follow the diagram on the fuse cover you'll see them in the middle i believe, I think two 40 amp and one 30 amp

bauermd

iTrader: (1)

Alright I took them both out for around 5-7 minutes without touching the battery and placed them back in and took the car for a 10-15 minute drive. The problem wasnt as bad as it was a few days ago but like I mentioned, some days the problem isnt there at all. It is definitely still present though. If I am at a complete stop and push the gas, the exhaust sounds like its bogging down for a split second then it decides to go slowly and the higher I get into RPM the more "pickup" the car has. I know its a honda and I shouldn't expect much from the low-end but the car hasn't always done this. Also it gets so bad sometimes where I almost have to completely floor the car to get it to go anywhere. No CELs or related engine codes at all.

Someone had mentioned a possible vacuum leak somewhere along the line which in my eyes makes a little sense but the car starts fine and idles completely fine. Maybe it gets bad sometimes to where the ECU is trying to adjust for the leak after the car has ran for a little while? But still doesn't explain why it does it sometimes and not others.

Also, I drove the car around 600 miles total last week (Fiance was in town) and I noticed that the car does it ALOT more around town when im doing a lot of stopping and going. It also will do it HORRIBLY, then it will all of sudden go away.

BukvaMan

I dont know man .... Ive had the car since 05 ( brand new ) I put so much time and effort into it then I could never get myself to sell it. But Ive been thinking about it many many times.... Its still in an amazing condition considering its almost 10 years old... not even 60 000 miles on it.

Even tough I can live with the way it drives now it still drives lazy in comparison to anything I have driven lately. I know its faster then some of them but it doesnt feel that way and its nowhere near as fun... maybe because its an honda i dont know....what i know it will my last acura or honda. I know some of the germans are not as reliable but whatever brakes can be fixed, this on the other hand is a freaking mystery...

I have changed abut everything one can change.

IAT Sensor
Knock Sensor
Coolant Temperature Sensor
Map Sensor
App Sensor
02 Sensors (upstream and downstrem)
All Spark Plugs and Ignition Coils
EGR Valve
All New plenum and throttle body gaskets
Brand New Die Hard Platinum Battery
and more...

One thing i have not changed is the Throttle body... maybe you can give it a try...

I changed the transmission fluid to redline (3rd and 4th gear pressure switches)

Exhaust modification ....

A lot of it improved things to a certain extend but never fixed the root of the main problem...

the VSA seems to be the closest though...

bauermd

iTrader: (1)

Exactly. I don't want to get too far into the moneypit with no results. There are no engine lights so the dealership pretty much wont even take it anymore. i have thought about local Honda shops but I can't find any in my area worth going to.

My though is if it was a sensor it would throw codes or run really rough or something.

I might to start looking for a slight vacuum leak here in the next few days but I work 12 hours a day everyday till tuesday.

Things i've changed:
-Sparkplugs
-Timing belt kit WITH oil pump and seals
-Belt tensioner with new belt
-Downstream O2's(which got rid of CEL)
-Transmission with OEM fluid (Car shifts completely fine)
-Coolant bypass

I am still hesitant to change the APP or MAP.... Maybe someone in the area would let me use their known good ones for a day or so?