Boosted11

iTrader: (11)

I need some advice on the afr readings i'm getting on my 87 t2. Definetly new at tuning, and just starting to get into it. I've always just driven my t2 stock, but now its time to climb the ladder.

My car has been running extremely rich. I get about 200km to a tank all city driving, roughly 100miles..... Bad isn't it? I decided to grab a wideband, and see where i'm at.

Mods:
Ported wastegate
Racing Beat REV TII exhaust
Racing Beat fuel cut controller

I recently bought a plx wideband, and installed it last night. The ratios I got so far, go as follows:

Idle:
Low of 14.2, High of 15. 750rpm.

50km/hr cruise:
Mostly stays at about 12. 2500rpm, 3rd gear.

Didn't log this to well by eye, but under boost is roughly 11.2.

Evidently the idle is outrageously rich, and I do know turbos run very rich at idle but is this reading normal? I'm pretty sure the 50km/h cruise is about right.

Aaron Cake

iTrader: (1)

The idle is rather lean. Though if you have the airpump installed, that would explain it.

At cruise, 12:1 is crazy rich. It should hover around 14.7 if the O2 sensor is working.

arghx

iTrader: (3)

you are too rich under cruise. is this the stock ECU? you may have a bad stock O2 sensor... you did keep the stock O2 sensor in there didn't you? You didn't just install the wideband in the stock O2 bung? If you did, it will burn out the sensor very quickly due to the heat of the rotary exhaust. The wideband needs to be installed in a new bung at the back of the downpipe but before the cat.

dean23

for a new tuner i will say this: idle afr does NOT affect mileage. get that idea out of your head if it is there. like aaron said, the cruise afr's are way too rich. i keep mine btween 14-14.7 and get around 20 mpg on the highway. not the best, but i am running a large streetport and full 3" exhaust, so im pretty happy with that. as far as under boost, try to keep at around 12.5-13 under low boost, (0 - 4 psi for me) and around 12 above that if you want to keep it safe. after that its timming adjustmens, but i woulnt recommend adjusting that until you have a proper egt monitoring system.

Boosted11

iTrader: (11)

Yes this is the stock ecu. Stock o2 sensor was just replaced recently, although it's possible that I have damaged the end of the wiring a few times. Wideband bung was installed at the very end of the downpipe.

Like I said i'm new at this. I assumed that going red on the wideband meant going rich so the higher the afr the more rich it would be, I guess im wrong. Now that explains alot. Under boost is around 12 which is bad, and at around 5k rpm 7psi I get as rich as 10.5! I've always thought that at the top end my car has been gutless.

I have no airpump. What would exactly explain this lean mixture, when I have done hardly any mods to the car? Besides the o2 sensor?

Aaron Cake

iTrader: (1)

Sounds like your O2 sensor is working fine. I forgot that with a narrowband, it will hunt around a little.

Frostycrowd

iTrader: (9)

Idle AFR does affect gas mileage. If you get 20 mpg but sit in traffic for 20 mins running tons of fuel its going to drop significantly.

Boosted11

iTrader: (11)

So I guess after o2 sensor, the next step would be timing? If that doesn't do it, I'll get my rtek 2.1 earlier for the soon to come bnr stage 3.

Aaron Cake

iTrader: (1)

Timing just doesn't change.

OK, I'm all screwed up here...My answers don't make any sense now that I've read them.

The idle is quite lean, which is also uneffected by the O2 sensor. It's ignored at idle.

Your cruise ratio is very rich, which SHOULD be effected by the O2 sensor. Is the sensor working and connected?

Something is wrong here. It sounds like the ECT may be faulty or disconnected.

dean23

frostycrowd, i gues i shoud have worded my respense better. an if your leaving your car on while sitting in traffic for 20 mins, you are an *******. and you generally do not group tuning your idle mixture with fuel economy.

to the OP, how are you planning on tuning with the ecu? piggy back? or are you just amused with the gauge.

Frostycrowd

iTrader: (9)

I have noticed slightly less fuel consumption by cleaning up a rich idle. When moving light to light in heavy traffic it is unpractical to turn the car off and on.

I understand uou not grouping fuel economy with idle. Just really depends on commuting situations.

Boosted11

iTrader: (11)

The weird thing about the idle, is the exhaust mixture smells incredibly rich. I guess the o2 sensor must be getting more adapted because the idle is about 12.5 now. Or I just messed up when writing down the recorded #'s at the first post.

The o2 sensor is connected. Like i've said in a previous post, I think the wire on the end of the o2 sensor was abused last time I took the downpipe off. I'm going to try replacing that again and if its not that, than its on to the ECT.

Nice re-wording your sentence, you spelled response wrong.

I'm planning on getting an rtek 2.1. But unfortunately winter is nearing and I live in canada, so when I get the rtek the car will be in storage.

HAILERS

A turbo car idles around 13.0 to 13.5 afr. Ah heck, my na does too.The 12 whatever is a bit too rich. A leaner afr at idle causes little pooops every once and a while. On the other hand I was told on this forum that his car idled at 14.8 with no airpump. Go figure (yeah, sure).

If the 02 narrow band is working with the ECU i.e. closed loop, the afr should be 14.8 give a little on either side. Like 15.1 on the high and 14.7 on the low when CRUISING.

IF your at a steady cruise, and Your afr reads 12 or 13 whatever, then your ECU isn't going into closed loop. NOT good at all.

Closed loop can be checked out in the driveway. One LED attached to the six socket, green check connector. The pos lead to the black/white wire in the top middle. The other lead to the the socket below that one. TPS disconnected, car fully hot. Start the engine and put and hold the shifter in 2nd, 3rd or 4th. No matter as long as it's in a gear (neuter switch in any positon but neutral is what I'm implying). Rev slowly to over 1700 rpm. The LED should start constantly blinking, at revs over that figure.

Closed loop cannot be obtained over something like 3500rpm if memory serves. You ain't (have not) been in closed loop in my humble opinion.

Yeah, 10.5afr in boost seems a bit rich. Too rich imo.

With a fully HOT engine, at idle, turn the variable resistor (series four only) clockwise til the wideband reads appox 13.0 to 13.5 afr.

Driving along at a steady speed and then just barely letting up on the throttle will result in the afr going about a full point richer. NORMAL. Deisgned like that. Letting off the throttle completly results in both injectors cutting off and a reading of>>>>>>depends on the maker or the wideband. A Zeitronix reads 21afr in that conditon. Just FYI and nothing more, nothing less.

Boosted11

iTrader: (11)

^ Awesome thanks for the info Hailers, that's what I was looking for. Your always a great help on this forum. I'll check everything you stated, in a couple days.

j9fd3s

iTrader: (3)

on an s4 there is a sensor on the bottom of the radiator that switches on the closed loop/emissions. the wires for the sensor like to get pinched under the battery box.

its easy to check

mazda tuned the car very rich stock, it has to keep running with low octane fuel, etc etc. basically the stock ecu is tuned as rich as it can go without misfiring, on a stock car. which is in the 10's

the leaner you go the more things like fuel quality, coolant and oil temps matter. the hotter the engine, and worse the fuel quality, the more valid mazda's tuning strategy is.

the goal is to keep the motor together, if you use your head, its not a problem

pistones

iTrader: (5)

i have a weird scenario, with the stock ecu car idled at 13.5 no problem. now with microtech it has a hard time idling at anything leaner than 13.0.

arghx

iTrader: (3)

upgraded fuel pump and stock FPR my T2 idled at 12.5:1 or so on stock ECU. But that was with porting.

Boosted11

iTrader: (11)

I did these tests today. Went out and got a test lamp, attached the red clip to the black/white wire, and the probe parralel to the black/white wire. I assumed the 6 socket green connector was next to the leading coil and washer fluid bottle? If I connected all of this right, then the results are i'm not going into closed loop. What would be the next step, to getting closed loop?

EDIT: **** I forgot to put the car in gear, I'll go try it again. Tried again and to no avail no led flashing.

I turned the variable resistor, and idle is now 13.5afr average.

Boosted11

iTrader: (11)

This car goes into storage in a month, and need to sort this out before then. So bump it up.

Osirus9

iTrader: (10)

I have a silly question. Where is the variable resistor on the s4 turbo? I have the same car as Travis v and just bought an aem wideband. I also have an safc, so should I use that to adjust the afr at idle, or this resistor?

I've got the RB rev II exhaust as well, but I didn't know you could not use a wideband to replace your O2 sensor. where exactly do I need to have this other bung welded on?

Boosted11

iTrader: (11)

The variable resistor is near the passenger strut tower, connects to a little bracket. You can identify it as R(rich), L(lean), shows you which way to turn for each.

DO NOT replace the stock o2 sensor, it's needed. Weld a bung at the very end of the downpipe. I put my bung pointing upwards near the tranny, obviously don't point it to the side or down so it doesn't get damaged.

Osirus9

iTrader: (10)

oh ok, I know what you're talking about now.

and I know you don't NEED your O2 sensor, I didn't use to have one for about a year and I didn't notice any difference. It wasn't an fc, but it was still an old *** car. All it does is adjust afr's a little while you are cruising. My main concern is that the wideband can get damaged by the heat... But I will get a new bung installed at meineke or something.

HAILERS

Hey. When you adjusted the variable resistor to richer, does your engine idle smoother now? Or not? Should be smoother.

I'll think about the 02 sensor not going into closed loop. Nornally it's the 02 sensors wire is disconnected.

Yeah, the green, six socket check connector is where you cited. Red LED from Radio Shack to the black/white and the other wire of the LED just below the black/white. TPS plug off, engine running and hot, clutch in and shifter in.....try fourth. Rev to approx 1700 rpm to 2500rpm and hold it there. LED should have lit up and flashed.

I"ve done that procedure a number of times. The only time it does not work is if the 02 is disconnected. To see if the 02 is connected, go to the ECU. Leave all plugs on it. Find the middle plug. Pin 2D is the input to the ECU from the 02. Backprobe that wire with the plug on the ECU. Meter on DC volts. Start engine and let it idle. With no airpump, the reading will usually be approx 0.80vdc. Rev the engine slowly and the reading should change.

Or to see if the 02 sensor is any good. Pull the plug off the 02 sensor itself. Put you meters positive lead on the 02 connector and the meter neg lead to gnd. Idle the engine. Reading will be something like 0.80vdc give or take. Rev the engine slowly up/down and the reading changes.

I always do that check with the six socket, green check connector prior to going to the yearly emissions checkout. Better safe than sorry.

HAILERS

Hey, about the LED deal. Do this. Install your LED in the six socket check connector. Look at it as you put the key to ON. The LED should have lit up for approx one to two seconds and then gone out. Did that happen????? No engine running, just LED installed and key put to ON.

HAILERS

Well. Ignore me for a while. I went out to try this out on my 86..........and failed. On my RTEK 2.0 it shows a 02FAIL once I get up to over 1500 rpms or so, but I"m reading the voltage output of the 02 on the RTEK.........so I'm confused right now about what MY problem is/are. I'm not convinced it's the 02sensor.

The LED should be lit up as you go from idle on up, and somewhere around 1700rpm start blinking on/off, showing the ECU is adding/cutting fuel to maintain a 14.7afr. Mine right now is just lit up and staying lit up.

Part of my problem, is, I've been mixing E-85 and have lost my mixture ratio of gas to ethonal and I need to burn off that last gallon in the tank and go get some of that $2.65 gasoline. Then start over.