RX-7 loving driver

On my a/f gauge when I 'am stepping on the gas its says its running rich. When I stop it goes to lean or sometimes it doesnt get a reading. It also sometimes moves up to stoich then back to lean, then back to stoich. When I first installed the gauge it always read rich all the time, it never moved, until one time I took the car up to 120mph, that is when it started doing this. Is this normal? Should I be concered? What can I do to fix it?

skunks

that is exactly what you are soppose to see. the only thing is that you should take your car to a dyno and use a wide band O2 sensor so that u know how your car is really running. the stock O2 sensor is not really that good/accurate and might be hashed already!

RX-7 loving driver

Thanks. So it should be fine then. I just got worried cause when I first got it it always was on rich and it would never change.

skunks

another thing you may want to check is if your connection of the wire is a good one, when mines acted up, it was because i only had a thread of a wire connection to the sender. make sure your connection is good.

By the way, you only get a relativly good reading if your at WOT. but again, the stock O2 sensor is not that good, you should get to a wideband O2 sensor if possible.

coop

I have a couple questions about that O2 sensor while we are on the topic...
What is a wide band o2 sensor? How much do they cost? Does it replace the stock sensor?
Thanks
-Dave

skunks

ok heres the deal, wide band O2 sensors are O2 sensors which accuratly measure how much O2 there is under all rpms unlike the stock one which is not terribly accurate and can only tell you stuff when your at WOT. a wideband O2 sensor does not replace the stock one unless you got tons of money, it cost about a grand and only last for about 600 hours (thats good enuf for most tuning). you also need to use a computer program to analyze the results. most dyno shops have this and charge about 40 bucks for an hour of use.

coop

Ok, so is there any good replacement for the stock O2 sensor? Maybe one that is a little more accurate?
Thanks
-Dave

skunks

im sorry, i dont know of any more accurate O2 sensors, the only thing you can do is to replace it more often, about 20000-40000 miles i think is how much they are worth, what i do know is that the stock one is fricken expensive, go to rx7.com and buy the 40 dollar boshe one which works the same as the one from mazda except its 150-200 dollars cheaper!!!

skunks

forgot to mention, you gotta let the stock one warm up before it will give u kinda accurate info, think of it this way, don't totally trust you a/f meter cuz it wont give you that type of info, just rely on it to tell you if your kinda in the rich or kinda in the lean. BTW: you want to be in the rich!!! detonation will kill your FD!!!

RX-7 loving driver

How do you make it run a little richer? What can you do to change it?

skunks

what you can do is to use a piggyback computer like superafc from apex to turn up the injectors a little or you could replace the CPU, go with a powerfc or haltec if your loaded with money. the last alternative i can think of is getting your cpu reprogramed by someone like M2 or someone like that. i personnaly like the superafc from apex cuz it have a look looking vaccume tube display which is relativly cheap if you know where to get it from. should be about $300 or so. good luck, by the way, dont turn your injectors above 85% dutycycle cuz your gonna burn out your injectors and run lean and then detonate and then you can kiss your engine goodbye!!!

to check your duty cycle your gonna need hks ipm which is 300 bucks or a powerFc, 1300 bucks!