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

 

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...