brandonfpv

I do have an OBD scanner that has a live monitor feature. What should I look for? There’s like 10 pages lol also there’s a “realtime curve” which shows me useful things like engine load and rpms.

Which by the way I’m at 600 rpms parked and like 500 lowest in drive or reverse(I find it goes lower in reverse, maybe placebo) and engine load is around 31-35% idle. So maybe a little low on rpms because headlights flicker but.. well everything flickers. It’s probably a little low. I do have Amazon led lights in, as previously mentioned. The lights itself don’t bother me, but it could be a telltale sign of something right? I have cleaned my iacv. I know one thing at a time, but this isn’t ancillary so…😂

car is technically safe but the red hot catalytic converter makes for a nice smell.. probably a mix of formaldehyde and singed insulation. Definitely can’t put my daughter in it, as of now..

P.s i havent seen the radiator fans go on once yet but I’ll worry about that later. Oh and the code is p1133 not sure if that helps.

Margate330

Awesome, now we can get some work done, looks like you are getting there.

Please post up your fuel trims using live data, like to see the actual numbers

You will see bank 1 and bank 2 fuel trims.
Need "long term" aka LTFT
and "short term" aka STFT.

Example:
Bank 1, LTFT 0%, STFT 3%
Bank 2, LTFT 2% STFT 0.4%

Extras, like to see the MAF value too plz.
Note- car should be fully warmed up at idle and in Park and all accessories off, to be meaningful.

Ps- I don't know that P code off top of my head so I will look it up when I have time or if someone has the info, please post it up for us.

brandonfpv

ok ok, gotcha. Well apparently the code is regarding hO2s sensor bank 1 upstream. Someone fact check me. I’m going to check spark plugs asap just because I haven’t yet (No tool).
Does the ecu adjust the fuel trims of each bank?

But I agree, I think the wheels are in motion. The smooth driving today just made me want to burst out crying.. until computer starts pushing out fuel. The burning smell and red hot cat is scary. Way less scary than before but we know what is happening inside lol. I don’t know why I thought this would fix the issue, it definitely has made it road safe but I think once this misfire is resolved I will have a powerfully running 1st gen RX (which is a huge flex btw)

edit: I think I’m going to just buy the sensor. Like you have said they go bad typically. If it doesn’t work I’ll return the part. How difficult is it to swap the bank 1 sensor 1?

brandonfpv

Alright guys I have performed some tests. I didn’t really know what to look for but I filmed some videos. This is with the car warm driving. Tried to include rpms in one video but it was dangerous lol. It appeared that Short/long term fuel trim for bank 1 was a little more stagnant if that makes sense? But bank 2 was moving quite rapidly. I’m not sure guys hope the video helps . Nvm I can’t post the video I want it’s too large I will edit it later but here’s idling at a red light

maxSteel

I think this is the video:

Margate330

Awesome video, enjoyed it friend.

maxSteel

He explains things really well. I learned a lot

Margate330

Hi Brandon, I saw your fuel trims and they are horrendous. lol

One of the good things about reading the fuel trims is zeroing in if it's a problem that affects both banks or just one bank.
Why this is so important is it narrows down the point if attack.

Ok, from your video:

Bank 1: LTFT= 50.0%, STFT= 19.5%, Total is +69.5% extra fuel added, Wowsers! haha
Bank 2: LTFT= -17.2%, STFT= 18.0, Total is +0.8%(within spec)

These numbers don't mean much for us if the car is not fully warned up at idle in Park. Changes in RPM's or speed moves the fuel trims all over the place so that's why we need to see the engine in a baseline condition- idle, warmed up, in Park, AC off.

PS- I haven't looked into it but can a dead A/F sensor cause the ecm to increase the fuel supply to the point of glowing catalytic converter? Of course I'm assuming a proper working exhaust with NO exhaust leaks between the engine and the Cats

brandonfpv

im really hoping this is the case because I am replacing the o2 sensor today. The mechanic I am working with is telling me that if we do replace this, we will most likely run into a cat code . Well here’s the fuel trims with the car warmed up in park idling, no accessories.

check this out guys I looked at the video and the short fuel trim bank 1 gradually increases:

https://share.icloud.com/photos/087O...sDFJGP8fmyVMVQ

Just watched that fuel trim video. I think it’s a vacuum leak. lol. Gonna check fuel trims again

edit: maf value is like 11-14 g/sec at idle. I have to test it again though rpms were at like 1000 ish

brandonfpv

Update: upon closer inspection you are right margate, my fuel trims are horrendous. bank 1 is always maxed out, long-term fuel trim, being at 50 something and short term usually 20 Sometimes zero. What the heck ..
Oh and I can’t get the o2 sensor off. I tried pb blaster. I don’t want to pay the mechanic, he didn’t put it on because he doesn’t want to charge me. I want to just see if this helps the issue. Should I use a blowtorch? I heard butane can’t be used but that’s all I have.

brandonfpv

Alright well I’m stumped. I’m going to hold on to the o2 sensor but I now don’t think that will help. The car wouldn’t run with a fully dead o2 sensor would it? Either way, I did a hard reset on the ecu with the battery and drove and idled fine, fuel trims were extremely low resulting it great fuel economy, and my catalytic converter didn’t glow red. I know it is a computer related issue. The mechanics tried telling me it could be mechanical and bank one is too difficult for them to test with their equipment, as he mentioned testing compression and fuel pressure/injection. Referred me to someone else. Not going to any more mechanics. I think I can do this. My solution to smooth driving was to shut the car down every 5-10 mins and turn it back on. Sounds stupid but didn’t give the ecu enough time maybe? I’m not sure. I don’t care but I’m getting both excited and annoyed. sorry if I’m being annoying this is so hard.

Margate330

Notice your engine load is below 20%, major improvement.

This video looks like a cold start or like you said- a battery unhook reset.

BTW, It's normal on a cold start for the fuel trims to go negative while engine is warming up.
It's also normal with a battery unhook reset for fuel trims to start negative sometimes while it learns the new fuel trims.

If you do have a major vacuum leak on one bank I would think it would throw lean codes for that bank but if multiple problems exist, maybe the ecm is confused.

An idea, can try unhooking the battery for a few mins to do an ecm reset and then hook it up and let it idle in park until it warns up a little and let us know the first codes that pop up.

PS- the "CL" in your video confirms you are in "closed loop" and the ecm is using the AF sensors to regulate fuel. If it doesn't say "CL:" it is not in closed loop and the ecm is using a default fuel map or something- the best I understand- it until the AF sensors warm up enoughh to go into closed loop.

Anyone else have ideas, please post!
That's all I have for now.

brandonfpv

That was not a cold start, that was warm and I idled for 20 mins last night with no code. This is what is making this so difficult. When I drive around I notice my fuel trims increase heavy on bank 1. They behave normal when I release the throttle, after I press the throttle really hard to burn the fuel that it is pushing out. it helps, then I let off the throttle and fuel trims return to normal. But it keeps trying to increase. Today I’m trying to get an inspection. Car ran fine to the gas station. They said I’d have to wait an hour for the inspection guy. As I’m waiting IN IDLE, fuel trims bank 1 start to go 30-40-50%. I do my little solutions like pressing on the gas and nothing helps. Now the fuel trim with the engine off but vehicle on reads:

SHORTFT1(%): 0.0
LONGFT1(%): 52.3
SHORTFT2(%): 0.0
LONGFT2(%): -11.7

Freeze frame shows that the engine is at idle when this happened. 740 rpm’s. I don’t want to reset it because I need to pass inspection, I believe since this is a ‘99 I can get away with a lean code. Oh and lean code is what popped up of course directly after the fuel trims started increasing. So annoying how it will drive perfectly fine until something wants to mess it up.

But okay I hear you. So everything was technically running as normal last night. Of course when I want to inspect it..

EDIT: Margate you are helping me realize what’s going on. When it goes from “CL” to “OL drive”
The fuel trims change for the better. When it is in CL is when it begins to fail. What is OL drive? Overload?

maxSteel

Open Loop vs Closed Loop. From https://shomespeed.com/blogs/how-to-...vs-closed-loop

"Open loop is when the ECU is not referring to the O2 sensor for feedback. Meaning that the O2 sensor might as well not be there, because the ECU is not using it to modify its timing and fuel maps"

brandonfpv

Oh great so I can almost guarantee it’s a sensor issue. But before I pay someone to help me take the sensor off.. (because i can’t and don’t want to strip it).. does this sound accurate? I mean all things are pointing to the sensor, including p1133. I did get a p1153 code yesterday but it went away and that was my first and only time seeing that.

listen I’m probably going to switch the sensor anyway. Just want to know if it is even worth doing.