My wideband reasing keeps changing??

[JoEgsX90]

whats going on guys i was wondering why my AEM wideband keeps having a changed reading at IDLE. i have a 190 rewired fuel pump with STOCK injectors. I also have a safc2 installed that is all zeroed out. Start the car up as usual starts lean then riches out about 12. something. have the idle at around 700-800 with my 272 cams. and when i try to lean it out to about 14.7 or so with the safc sometimes it'll lean out but then sometimes rich again at idle then ill try to lean it out more but usual sometimes comes back to being to rich. it seems alittle iratic? any suggestions?? Any one know with my stock injectors and 16g and 190 rewired how much fuel i should be taking out at idle. Will a logger help me at all im looking to get one ASAP

 

[Colt4G63 also]

If you have the correct fuel pressure, and the original injectors, and your only modification is the replacement fuel pump, I can't see any reason you would need to tune at all. Maybe your front O2 sensor/signal is screwed up.

 

[JoEgsX90]

Yea stock injectors with a rewired 190 fuel pump and its reading rich... So your saying with just a rewired fuel pump i should NOT be running rich? Cheak my profile for all my upgrades have a built 6-bolt block 7bolt head 272 cams 16g front mount ect...

 

[spawn87]

well i would turn of your safc to see if it has an affect...and as for your settings change them cause as far as ive herd when running fual management system you want to start at -10 on all lines for the 2g dsm. its a way to compensate for the extra flow.

look at these to give you an idea of what your doin. and good luck


http://www.dsmtuners.com/forums/art...tuning-guide-beginner-intermediate-tuner.html

http://www.dsmtuners.com/forums/articles-tuning-ecu/105569-how-safc-works.html

 

[->PrOjEcTGS<-]

Are you letting it get up to operating temperature before you are making any changes? I suggest you pull all the settings back to 0 across the board Lo and Hi. When you first start the car it will run on an open loop /fuel enrichment map. That is why it's crazy rich when you first start it. Then it will kick into closed loop and cycle around stoich 14.7:1. Sometimes higher sometimes lower. It's the ecu richening it up then leaning it out to hover around that 14.7 mark.

You need a logger.

With a logger, this is how it works on a 1g. You can look at the O2 trim. This is what the ecu is currently trying to do. It should be hovering around 100, sometimes higher sometimes lower. On a 2g it's 0. Less than 0 and the ECU is leaning it out. Anything above 0 and it's richening it up. If the average of this trim is above 0 it will change the low fuel trim to richen things up over the long term. And vice versa for if it needs to lean things out. Therefore, it's virtually impossible to fine tune closed loop because the ECU is always fixing your corrections based on the o2 sensor's reading. Unless you're so far off that the fuel trims are maxed out and cannot compensate for changes. The best thing you can do is get your trims as close to 0 as you can.

On a 2g I believe they change this where the O2 trim is called the STFT (Short Term Fuel Trim) and the LTFT (Long Term Fuel Trim)


Bottom of the line... Since you have stock injectors and a stock maf, your ECU is calibrated to those and your fuel trims should be at or close to 0. If your trims are not close to 0 +/- 5 then something is wrong. O2 sensor, Plugged Fuel Filter, Boost/Vac leak, possibilities are endless. Until you get larger injectors, you should not have to make changes to the stock tune with the AFC since the ECU will/should make those adjustments for you. The only thing you should possibly think about is leaning the Hi side of the SAFC out a little bit till the WBo2 reads about 10.5:1 AFR @ WOT.

 

[Colt4G63 also]

Yea stock injectors with a rewired 190 fuel pump and its reading rich... So your saying with just a rewired fuel pump i should NOT be running rich? Cheak my profile for all my upgrades have a built 6-bolt block 7bolt head 272 cams 16g front mount ect...

Yes! What I'm saying is that a fuel pump rewire is not cause to re-tune.

What ->ProgectGS<- said pretty much sums it up in more detail.

 

[cmaher]

depending on where u have the wide band at could be why its flucuating...it has to be 36in back off the turbo...i know a couple people that just try to screw it in where the front o2 sencor is

 

[JoEgsX90]

Thanks for the replies! I put my wideband sensor in the rear o2 sensor in my exhaust because i have NO cat. Yea well i noticed maybe im right that, yea when its warming up i can tell its in open loop. Then RPM"S drop around 800 then sometimes i feel like it goes from open to closed loop because i can see rpms going alittle up and its adding fuel. This is all with the car warmed up.. What would cause it that i should cheak to go into open loop at idle when the car is warmed

 

[steve]

What would cause it that i should cheak to go into open loop at idle when the car is warmed

fueltrimupdatepoints [ECMTuning - wiki]