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O2 sensors don't really give consistently wrong readings when they die, they give no readings at all or jump all over the place randomly. So I still think it's just reversed injector wires/positions, but I suppose you can unplug the front O2 and see pretty quickly.
I in plugged it and it idles now going to buy a new front o2 sensor I’ve also noticed every time It give a different reading thanks for all the help tell you if the new sensor works but I did make the mistake of putting the injectors backwards in the beginning
Hey guys i replaced the sensor let it learn and took it on a 20 min drive. During this drive it was idling for the first 17 min but it started dying .My MAF is still reading quite low and it is still switching between closed loop fault when idling and closed loop when driving not sure why this is and it never goes in to open loop just open loop fault but i noticed no issue when doing so. The car was also pulling no fuel from the long term trim the most it would pull was 0.8. do you think that the dying in the end will smooth out with time or what do you guys think
Hey guys im very confused now the car feels alot smoother now and idles more often but is very random it will only idle unless it pulls 14% of fuel on idle and deceleration and other wise it pulls no fuel is this normal i just feel like after the first drive of learning it refuse to idle i did strip the thread when taking the o2 sensor off it was ceased and when i chased the threads it was side ways and there is a tiny leak next to the o2 sensor i know that this could cause the idle but the doesnt explain why the car will not idle otherwise please help
Oh NO! how bad did it cross thread? What do you mean a small leak next to the O2 sensor? like a crack or rusted exhaust pipe? Sorry to hear it was stuck. does it still have a leak? Reason why i ask is because Wide bands are very good at sensing O2 it could be throwing it off at idle. Any other exhaust leaks? manifold or anything before the upstream O2 sensor? Keep in mind we want to rule out the easy checks first then go deeper as we verify the majors. Then we can go to the minors. These things do take time and lots of testing to prove or disprove probable cause. We will get it you'll see. LOKI?
Oh NO! how bad did it cross thread? What do you mean a small leak next to the O2 sensor? like a crack or rusted exhaust pipe? Sorry to hear it was stuck. does it still have a leak? Reason why i ask is because Wide bands are very good at sensing O2 it could be throwing it off at idle. Any other exhaust leaks? manifold or anything before the upstream O2 sensor? Keep in mind we want to rule out the easy checks first then go deeper as we verify the majors. Then we can go to the minors. These things do take time and lots of testing to prove or disprove probable cause. We will get it you'll see. LOKI?
it will idle but a little idle hunt if I give it the time to learn but my battery kept falling off so it kept forgetting so I fixed the issue with the battery but now I need to let it learn is it normal for the LTFT being at -14 to -20 at idle and decel AND WILL NOT IDLE OTHERWISE when just driving it will go to zero or adding any throttle the leak is still there is by the threads of the o2 sensor so I am going to try to tap it again and hope it doesn’t go sideways there is no other leak before the o2 sensor
Last edited by omar10910; Jan 28, 2025 at 12:14 PM.
after letting it learn again today it was idling nicely and again by the end of the drive it stopped idling and i have a p1688 that i have to fix now ive been dealing with this for a while now i might just buy a new one its been on and off i also noticed that even though its pulling the 22.7% at idle its still dying so im just very confused now what could be this on and off that it will be idling in the drive and then stop could it be a stuck valve and if it was due to the exhaust leak would it not be reading it as lean and adding fuel? same with vaccum leak please help
Oil metering pump switch working? I heard guys take it off manually cleaning it and putting it back on so the switch works. Ok so yes you are correct that if the O2 sensor is reading too much O2 it will add fuel to the LTFT. Hey question is there a way you can try something? start the car, open the hood and grab a can of carb cleaner. When its starts acting up spray some carb cleaner in the intake somehow so is not to disconnect the MAF in the process. ( maybe sneak the spray tube in a vacuum line?) Its time to get down and dirty. This is all assuming compression is good when Hot and you said it starts hot so no worries. IF the idle smooths out with some added fuel with carb cleaner then its actually starving for fuel. If it gets worse then we know its Too rich. Other way to do it is locate your Fuel pump relay and start it and do the same with but instead of the carb cleaner, pull the fuel pump relay or fuse momentarily and see if that idle smooths out for a second. We need to give the engine what it wants. So lets ignore the sensor readings in this test. We are going by how it idles with manually giving or taking away fuel...
You might have a bigger exhaust leak at the exhaust manifold, but thr thing is, any exhaust leak would be pretty apparent by sound and visible exhaust...
What about the jet air nozzles? Are those routed to the intake correctly? They're at the bottom of the LIM and are specifically there for idle stabilization.
You might have a bigger exhaust leak at the exhaust manifold, but thr thing is, any exhaust leak would be pretty apparent by sound and visible exhaust...
What about the jet air nozzles? Are those routed to the intake correctly? They're at the bottom of the LIM and are specifically there for idle stabilization.
the jet air nozzles are connected but I will double check to see if they are leaking there is no other leak in the exhaust manifold but there is a leak in between the header and the mid pipe the gasket broke I don't think it would affect the 02 sensor also there is the leak by the thread I know that can affect it but would it not be adding fuel due to the extra oxygen not cutting it?
Oh! Well. A leak at the header can definitely affect it. You're sucking in fresh air between exhaust pulses try to at least temporarily seal it and see what that gives you
after doing this it seems to be catching its self as its dying when a give it a spray and yes compression is good so it is leaning its self out
Ok so, im seing a trend here. Ive done some research and the rx8 has a "learn" function and that has a fuel table correction and applies it to the main table. So when you have a exhaust leak the table is adding fuel to reach a target AFR BUT when you fix a leak or get a working O2 sensor it needs to relearn. if it doesnt it will bass the O2 readings off the "saved" map so if it reads that richer then it will pull fuel. The main thing KAM stores are things like fuel trims etc. It's useful to reset KAM when you have lean/rich codes where the fuel trims have been able to reach 25%. It takes a while even after repair for the fuel trims to go back to proper levels, if you clear the KAM it will reset them to 0%.
How do you reset KAM? Two easy ways, disconnect the battery and leave it like that for at least 10 minutes, sometimes longer. To expedite the process disconnect the battery and hold down the brake pedal, itll drain the KA power quicker. This will allow all codes to clear and KAM to clear.
After some research, at this time, it seems pulling the Room Fuse on the interior fusebox will also clear only the KAM. Not 100% sure yet, but pretty close.
Ok so, im seing a trend here. Ive done some research and the rx8 has a "learn" function and that has a fuel table correction and applies it to the main table. So when you have a exhaust leak the table is adding fuel to reach a target AFR BUT when you fix a leak or get a working O2 sensor it needs to relearn. if it doesnt it will bass the O2 readings off the "saved" map so if it reads that richer then it will pull fuel. The main thing KAM stores are things like fuel trims etc. It's useful to reset KAM when you have lean/rich codes where the fuel trims have been able to reach 25%. It takes a while even after repair for the fuel trims to go back to proper levels, if you clear the KAM it will reset them to 0%.
How do you reset KAM? Two easy ways, disconnect the battery and leave it like that for at least 10 minutes, sometimes longer. To expedite the process disconnect the battery and hold down the brake pedal, itll drain the KA power quicker. This will allow all codes to clear and KAM to clear.
After some research, at this time, it seems pulling the Room Fuse on the interior fusebox will also clear only the KAM. Not 100% sure yet, but pretty close.
You're describing long term and short term trim. Long term is learned, short term corrects the fuel dosing based on O2 sensor signal at the moment. Learning trims doesn't take particularly long, it should adjust to changes within a drive cycle or two.
While you're pulling the battery to reset trims, not a bad idea to reset NVRAM as well: press the brake pedal 20 times in 8 seconds with the key in "ON" but not running. The oil pressure needle should do a sweep.
Is the header gasket leak near the siamese port or one of the outer ports? If it's one of the outer ones, it would offset one rotor's O2 reading vs. the other, which would be very confusing to the ECU as the AFR it read would oscillate and never settle.
That aside, I still think something here is miswired and firing out of order, confusing the ECU. Spark plugs, ignition coil harness, injectors, maybe wrong vacuum routing. It makes no sense for it to pull fuel while also reading lower than actual airflow, and I don't think it's the O2 sensor without a code.
When you say spraying starter fluid helps it not stall, does that mean you have the accordeon off and you're spraying into the throttle body? So the MAF isn't reading anything useful?
You're describing long term and short term trim. Long term is learned, short term corrects the fuel dosing based on O2 sensor signal at the moment. Learning trims doesn't take particularly long, it should adjust to changes within a drive cycle or two.
While you're pulling the battery to reset trims, not a bad idea to reset NVRAM as well: press the brake pedal 20 times in 8 seconds with the key in "ON" but not running. The oil pressure needle should do a sweep.
Is the header gasket leak near the siamese port or one of the outer ports? If it's one of the outer ones, it would offset one rotor's O2 reading vs. the other, which would be very confusing to the ECU as the AFR it read would oscillate and never settle.
That aside, I still think something here is miswired and firing out of order, confusing the ECU. Spark plugs, ignition coil harness, injectors, maybe wrong vacuum routing. It makes no sense for it to pull fuel while also reading lower than actual airflow, and I don't think it's the O2 sensor without a code.
When you say spraying starter fluid helps it not stall, does that mean you have the accordeon off and you're spraying into the throttle body? So the MAF isn't reading anything useful?
the header leak is not from the header to engine its the gasket in between the mid pipe and the header broke and I never replaced it I will also fix the leak by the o2 sensor ive just been a little busy I will try to get to it today I will look over every thing the injectors and the coils make sure its all wired correctly I'm sure primary injectors are correct I never looked over the secondary I probably should have but oh well I'm also sure the coil wires are correct and I was spraying the carb cleaner from where the filter would be I just lifted the whole box and opened it to spray I will make sure there are no leaks and I will see again thanks for all your guys help
I was thinking about vacuum and I remember that I put on my 2005 intake manifold because I wanted to rule out the intake manifold having a leak but it had an extra vacuum line on the back where the oil goes down I don't know if that could affect it I also know that the 2 ports on the side of the LIM were connected and put to the accordion tube right now I have it capped them off individually
I'm having a hard time understanding the last post. Nothing on the LIM should be capped off, there's really only the jet air line, which you really need to be connected to vacuum.
Spraying carb cleaner on the MAF isn't the best idea, can ruin it. That's why there are special maf cleaners.
I'm having a hard time understanding the last post. Nothing on the LIM should be capped off, there's really only the jet air line, which you really need to be connected to vacuum.
Spraying carb cleaner on the MAF isn't the best idea, can ruin it. That's why there are special maf cleaners.
no it looks different there is another intake line where I circled
Oh those. Yes, this was a fix for frothy dipstick problems 2006+. Routs to the oil fill neck but fine if capped off. Forgot about those. As I recall, what you have circled doesn't route to the intake, just straight to those 2 diagnostic ports on the LIM. If it's all capped on both ends that's fine too for now.
alright I was just wondering do you think it could be the issue of switching from the 2006 and up manifold to a 2004-2005 I don't know what year the engine but I know its above 2006
If the manifold is from the same type of engine, it should be fine. Meaning, if you have a 6 port, with a 6 port LIM, it's fine. I suppose you couldn't really attach it otherwise.
Yes it is LTFT and STFT, and learned is also from the O2 sensor Just (stored data table over time). I was saying this problem needs to have a clean slate whenever we make a change to 8 weather it be new parts or fixing leaks, so is not to chase our tails with a learned Table. So yes reset the ECU when ever you make a change that way we start from a LTFT that is 0. Newer intake manifold should not be a problem as long as the ECU has the correct data from the MAF and the 02 sensor and there is not a vacuum leak.
If the manifold is from the same type of engine, it should be fine. Meaning, if you have a 6 port, with a 6 port LIM, it's fine. I suppose you couldn't really attach it otherwise.
yeas it is both 6 port I will try Dust8's suggestion
hey guys I know its been a while but I'm back I was busy working on my friends rx8 I was putting in an engine for him and his idles perfectly I'm going to be using his for a base "map" to see what this should be reading at certain rpm I've so far fixed my exhaust leak and I'm planing to go tear down the UIM to get to those injectors I believe that's what it must be because I feel as if I've exhausted all other options it may be a leaking or clogged injector I'll make sure that the wiring harness is on correctly this is my last option. I remember that I broke a piece of the (APV) motor while putting in the engine I broke that little grey piece off of it do you think that this could be the issue I'm just cover all bases at this point Thank you for all of your time on helping me with this I really appreciate it.
