lean AND rich??
 

hello, my car has been running lean ever since i bought it (i have a a/f ratio gauge, it idles at about 20-21) but when i check the spark plugs, they are black like they are running rich.

my car:

i have a streetport, and i just got done doing a silicon hose job. When i first started the car after the job, it ran perfectly with a a/f ratio of 14.7 and idled perfectly. however, the 2nd time i started it up my idle went rough and i had some afterburn noises, and after it was heated up fully, my idle would die for a sec and then recover like little falls and jumps on the rpm gauge. oh btw, there is kind of a light squeaky noise when i floor it fast or when im at high rpm during a small drive. My car's warm up system is was fine during that first start up too, but after i did the 2nd startup and since, it goes to 3k but then stops at 2k and doesn't go down unless i unplug the blue solenoid in which my idle gets a little better, but my a/f ratio goes to about 14.2 (idk what this is or if it matters)! adn then the idle just stays at like 1500 after i plug it back in.

i do not use this car daily, i am working on it, so it sits in the garage. idk if they would help but its just info haha. Now, BEFORE the hose job, my car still was running lean but the afterburn noises were alot worse and it wanted to die when i would drive it then stop somewhere.

could someone please help my diagnose this problem?

if you need anymore info just ask! idk what this is and i've been searching for a good month. and i need my car soon cuz i need to get a job for summer :/

Damaged O2 sensor? 21 AFR at idle is a bit hard to believe..

Especially considering that afr is right at the edge of flammability.

What KIND of A/F ratio gauge? And What KIND of O2 sensor...

If that sensor is stock or has less than four wires and if you paid less than $150 for that gauge, you've got a Narrow band gauge, which I think are useless.

Air Pump is probably dumping into the O2 sensor at idle.

The exhaust is probably mixing with the pumped air, giving you the lean readings. However, your combustion mixture could be rich.

^^ Another good possibility, but 21 seems a bit high? and isnt port air dumped into the cat?

yup the afr is about 21 at idle, but i have a fuel controller so i bumped it down to like 18. idk what kind of o2 sensor or gauge cuz it was on the car when i got it (same with the fuel controller). So i will go check out the 02 sensor right now and see what i find.

Port Air is dumped into the exhaust PORTS which are located.....................prior to the 02 sensor. Then it goes on to the catalytic converter.

There's been no mention as to if the airpump or ACV is still on the car.

Most 02 controllers have the manufacturers name on it.

hmm. So the air in the cat is Split air?

Most of the air supplied to the cats comes from the port path (exhaust ports -> DP -> cat). The split air path does go directly to the main cat, but it barely flows at all until you're in 5th gear. You can pass the sniffer part of a smog test w/out the split air pipe. This is on US-spec cars. J-specs have the split air path open more often (no split air solenoid).

But back to the original topic, 20:1 is what a wideband reads when there is zero fuel going in and you're in decel. I would think you'd see #s somewhere in the high teens if the air pump was dumping air into the exhaust.

Like 88 said above.

The air goes to the exhaust ports sleeve area to mix with the exhaust gasses. The way understand this. this is to get the exhaust gasses to read close to 14.7afr prior to reaching the converter. As THE BOOK mentions, the converter is most effiecient when the gasses entering it are in the 14.7 afr range.

Once the car is in motion, fully warmed up and being driven down the street, the 02 sensor and its feedback to the ECU make the car go into closed loop. Closed loop means afr in the range of 14.7afr. So at this point there is no real need for the airpump/ACV/air to the exhaust. Right? Right.

Split air does not do that much in life in my very humble opinion. There are times when have been driving over 120 seconds steadily, when all the airpump air goes overboard into the right front fenders silencer. See what I mean? Yes.

And the Split Air Solenoid on the ACV activates when fifth gear is selected, adding a bit more volume to the air in the split air pipe, but if you ever really look at it, when your in fifth gear, the relief valve in the ACV is fully open to relive the air pump air to the silencer in the right front fender.......................so I ask myself, just how much air can really get into the split air pipe via the Split air solenoid. What with little to no pressure to send it to the split air pipe (remember the relief valve is fully open to the silencer in the fender).

I know the jpg attached is talking about the 02 sensor and closed loop, but the same OBJECTIVE is being obtained at idle and low speeds , by the ACV and its control solenoids (relief, switching solenoids) by adding fresh air to the exhaust ports on the engine.

OH yeah. Let it be known to the thread owner that the wideband sensors/controllers show a lean mixture for the first minute or so on engine startup. The sensor has to get up to operating temperature in order to send a accurate afr signal.

Air is not added to the exhaust system to make the O2 sensor read 14.7:1. It is added to the system so there will be enough oxygen present to burn off the remaining particulates in the exhaust system that were the result of incomplete combustion. These can't be burned off without the presence of oxygen. A 13B can not pass emissions at low speeds without an airpump for this very reason. It could at higher speeds but that's not where most emissions tests take place anyways.

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Nowhere above did I even mention air was added to the exhaust ports to make the 02 sensor read 14.7 afr. It's NOT the 02 sensor that matters at idle in any way shape or form. We all know closed loop only occurs at driving speeds and rpm over approx 1500 rpm and the 02 has no play at any speed under that. You can Trick the ECU to go into closed loop in the driveway, but that's another matter. Not a normal thing.

I wrote that the air is added to the exhaust gasses to make the afr mixture read closer to 14.7 afr BECAUSE that is the reading/mixuture the catalytic converter works at best. See jpg in my other post.

A normal half ass good idling RX has a AFR of approx 13-13.5 afr at idle if you disable the airpump. When you put the airpump/ACV back into the system the afr will read in the 14-16afr range due to the Port Air.

I DID write above that once the car is moving and actually being driven down the road, the 02 sensor and ECU working together go into closed loop and the afr in closed loop is approx 14.7 afr , and again if you read the jpg attached above it indicates that is the afr the converter works best at.

Air is NOT always injected into the exhaust Ports. After steady driving for approx 120 seconds, the relief solenoid de-energizes and causes the relief valve in the ACV to open and dump the air into the silencer, so when that happens there ain't no damn air going into the converter. Been there seen it too many times.

Not sure why the hostile attitude. I didn't claim air always goes into the exhaust. It depends on many things and can be sent to the exhaust ports, to the cat, to both, or to neither. I did however contribute and explain why air is injected into the exhaust system which is something no one else said. It is there to supply the needed oxygen to help the remaining elements to burn off.

Now saying that, the air is not injected because the cat works most efficiently at 14.7:1. That's not true and your pdf doesn't even say that although you somehow are interpreting it that way which is wrong! The cat works best above a certain temperature, not a/f ratio. The hotter the better. The downside is we have to balance that heat with cat life as too much heat will kill it quickly. Not enough heat and it won't do it's job effectively.

The 14.7:1 afr has NOTHING to do with the cat. It has everything to do with being the theoretical ratio (using gasoline) at which the engine burns up all the available fuel and air resulting in the lowest emissions. Now we know that's in a perfect world and since we don't live in one, there are some leftovers. That is however where most of it is burned up. The remaining amounts that aren't burned up go out the exhaust. The cat's job is to heat up and provide a large surface area over which to allow these leftover emissions to finish burning up and hence convert into less noxious emissions. However depending on several variables, it may or may not need help from excess oxygen to do so. Adding air through an airpump supplies this oxygen when necessary. Depending on the exhaust velocity it may be more benefical to either supply it to the exhaust ports or farther down in the cat itself. At other times it isn't needed. The more efficient your combustion, the less you'll need an air pump. Most cars today only use an electric airpump to clean up emissions immediately after the engine is started and nowhere else. That's because an engine runs rich until warm (it needs to) which means the odds of unburned gasses going out the tailpipe is higher and will hence need more air to help burn it off in the cat.

No. I'm sticking with the idea that the air is sent to the exhaust ports when the car isn't in closed loop, to obtain a afr of close to 14.7afr which the converter can more easily do its job.

When in closed loop the port air isn't needed because the ECU/02 sensor re controlling the afr close to 14.7afr without the need for addional air.

It's similar to having a setting a 750 rpm idle with the BAC nulled out, then when the BAC is put back in the system it does not have to work as hard to recover from loads put on the engine.

You go ahead and stick with your idea.

well i took off my o2 sensor and its a single wire. it is covered in white stuff so its running lean right? and i was inspecting the wire that the o2 sensor was connected to and the guy who had the car before was a dumbass cuz there was 3 wire connectors keeping the wire together. i wonder if the breaks in the wire might change what my o2 sensor is reading because of the added resistance in the wire??

i don't know jack squat about o2 sensors, and the whole exhaust ports thing im actually not all that familiar with, i've never really looked into the rx7 emissions stuff. so im going to try to test or replace the 02 sensor...but i'd appreciate it if somone could simplify the whole exhaust thing that was being talked about.

thanks

david

That doesn't make any sense. A wideband O2 sensor will always have more than one wire; they're heated. It sounds like you're looking at the stock narrowband sensor near the exhaust manifold or turbo. If you have a gauge in the car that gives you AFR numbers (not little LEDs), you have a wideband O2 sensor somewhere else in your exhaust.

Also, white/light tan build up on an 02 sensor is normal. 90% of driving is done around 14.7 AFR. You can't jump to the conclusion that you're running lean based on its color. Same goes for reading spark plugs. Unless it's a dedicated track/drag car, there's a whole lot of "lean" condition driving to create light colored deposits.

lol whoops ok i guess i took out the wrong sensor. like i said before i don't know anything about o2 sensors. sooo i guess i'll take out the other one XD

took out my wideband o2 sensor and it seemed perfectly fine when i tested it but im replacing my stock one cuz it looks like it might be bad when i tested it...i'll probably be getting it in about a week and then i'll put it in and post what happens

in the meantime if anyone has an idea of what could be the problem if its not the o2 sensor feel free to comment...

Does your car have the stock airpump and the ACV on it?

What is the name brand on your oxygen sensors display? Or the name on the wideband unit/controller?

it is a innovate motorsports wideband sensor and apexi fuel controller. and i have the stock airpump and acv.

nobody has addressed whether or not unplugging that blue solenoid connect is supposed to richen my car. the high idle issue has been fixed somewhat because i found my fast idle cam was off, and i fixed it. now it just idles a little higher than normal (like 1200-1100) but still has all the other problems :/

IF your car is a 91na like I read in another thread by you, then if you remove the Blue plug from the Relief solenoid on the left side of the engine, you will THEN read the real afr the engine is running at. The airpump air will not go to the exhaust ports now but get dumped into the silencer in the right front fender.

IF you put the Blue relief solenoid plug back on, then the air from the air pump will again be mixed with the gases from the engine and give a false reading of the afr being burnt in the engine.

You know where the 02 sensor is. So you realize if the airpump air is dumped into the piping prior to the 02 sensor your going to get a false afr reading. Right? Right. IF no air pump air is dumped into that piping, then your going to read only the exhaust gasses and the afr reading will be the real thing.

On a normal car the afr will be in the low 13afr. If the airpump air is dumped into that pipe the reading will go up into the 15-16afr readings because of the exhaust gas being diluted with airpump air.

so something is dumping too much air into the exhaust if the reading is only supposed to be around 16? would this be an acv malfunction or an airpump problem?

I'm really just saying that with the airpump and ACV working on a stock car, the afr reading at idle is a worthless reading more or less, because it does not represent the real afr being produced by the engine management system.

When your driving the car and smash the gas pedal, then the afr reading is meaningful because there is no airpump air being mixed into the exhaust gases at all (due to how the Relief/Switching solenoids work in conjunction with the ACV).

IF this is a non turbo car you can eliminate the effects of the airpump by just reaching over to the left side of the engine bay and disconnecting the Blue connector on the Relief solenoid. That act causes no vacuum being sent to the relief diaphragm (sp) inside the ACV which in turn causes the airpump air to be dumped into the right fender area instead of the exhaust ports.

Try that sometime in the drive way. Get the engine up to temperature and read your afr gauge. Then while still idling go pull the Blue elect plug off the solenoid. Then read the gauge again. It should read in the 13afr range now, proving what I just wrote is correct.

Turbo cars don't work that way, BUT if you had a turbo car, you go to the ACV itself, and pull the vacuum hose off that sticks straight up (and plug the vacuum hose with something to prevent vacuum leaks) the same result will happen as pulling off the Blue connector on the non turbo car.

High afr numbers at idle on a car with a functional ACV/airpump is nothing to be alarmed about. Normal as apple pie and ice cream.

JUST IN CASE: The airpump air has nothing at all to do with the actual running of the engine. As in NO effect on the air/fuel mixture inside the rotor chambers at all. None at all. The airpump air just gets mixed into the exhaust gasses After the combustion inside the engine to aid the catalytic converters performance.

What the airpump air/ACV will do is confuse people as to what the engines afr really is........until they figure out what is happening if the ACV and airpump are left in place in a stock fashion.

Disabling the airpump/ACV (as in pulling the Blue connector off the relief solenoid) for Extended periods of time will do the expensive catalytic converter no good.

ahh yes, well i replaced the o2 sensor and oulled the blue plug etc. and my afr does go down to about 13-14. so you were right, thanks

but my car still sounds like it runs a little rough and has the afterburn :/ but i did notice that it seems to get a little worse when it warms up fully...

If it were a series four car, I'd suggest turning the variable resistor clockwise to richen up the IDLE mixture. But since you have a series five........no can do 'cause series five have no variable resistor.

Part of your problem MIGHT be the porting of the engine. Got me. No way to tell from here. To hard to figure out idle problems on the net.

On a series four car, if I saw a close to 14afr at idle and had a kind of funny idle, I'd richen it up with the variable resistor till it read close to 13afr for a more steady idle. Like in no more tiny missing sounds when it was at 14afr.

well, i think i'll make a video so hopefully someone can listen to what my car is doing, but im also worried that the previous owner didn't know what he was doing and might have switched a wrong vacuum line and when i did the silicon hoses, i simply reconnected a wrong line...so im going to check that out too.

oh btw, i think i have racing beat exhaust, and i also have RB headers, would the type of exhaust system just simply cause afterburn? (just a question) or would an exhaust leak cause afterburn?

The stock car had a ACV and airpump. The ACV has an internal valve called the Anti Afterburn valve. You let off the throttle and that causes that valve to inject air into the primary intake runner to prevent afterburn. That said, I've run without a ACV and experience no afterburn.........if after burn means popping in the exhaust...backfire.

Mabye it's a timing issue?

now that i think about it, the timing hasn't been checked in a while i'll re-check it today when i do a small video of my car :icon_tup:

update
 

well i put a video of my car on idle on you tube just in case anyone wanted to see what was going on

this one is normal idle with the afterburn popping:http://www.youtube.com/watch?v=uEeae6hg7Mo

this one is with the blue plug disconnected: http://www.youtube.com/watch?v=q3OxLDrugxc

the 2nd video the plug was already disconnected my friend was just showing that.

get this: today when i started my rx7 i noticed that when it wa cold, it ran pretty decently with no little pops from the exhaust! but as it warmed up, and i watched my a/f ratio gauge, i noticed that as it warmed up it got leaner! so now i need to figure out why it is doing that.

A normal RX-7 engine runs at least a full AFR richer when cold and does not run normal AFR til the water temps get over approx 120*F. As an example it might show 12afr when cold but when the water temp gets up to over 120*F it'll read lower i.e. 13afr. The afrs are just an example, not exactly what you might see if you have a wideband.

i see, but when i started my car cold and i got my a/f ratio on my gauge it hovered around 16, and as it got warmed my gauge worked its way up to its 21-22. and if i remember (idk if it was just an example) you said my a/f ratio would be around 16 with air from my exhaust ports, so why is mine so high? it runs a decent a/f ratio without the blue plug but then i get hella air when it is plugged in it seems like. and when my car had that a/f of 16 my afterburn popping was almost gone completely. is this amount of air from the air pump normal or is there something wrong? :/

Probably normal. Depends on how good the airpump is.

Just remember that airpump air has nothing to do with the real afr being spent in the rotor chambers.

Only pay attention to the afr if the blue plug is off and or the airpump is disabled. There's no air going to the exhaust ports then and therefore no air being mixed with the exhaust gasses from the rotor chambers, so the afr read under those conditions is usefull information.

Other times the afr will be a true reading, is if everything is connected up as stock and you floor the gas pedal. That is a real afr reading because the airpump air is being dumped into the right front fenders silencer (next to the washer reservoir).

ok so i will no longer pay attention to that. But now im left with why does my car get worse as it gets warmer? i think that my car is misfiring since other cars seem to do the same thing. where should i start checking if it is?

LMAO you bought that car?! a friend of mine used to have it, its cool.

um 1100rpm with no load = popping, its normal every rotary will do it

...wow small world eh?

? why would it pop under no load? my friend's s4 doesn't pop at all...