S13 sr20T28 15lbs550'sZ32 mafSafc II I tuned the car myself with a wideband and it isn't my first one. Before I get an ear full about the Safc tune it's what I could afford at the time and I know there's better ways. Question is my air fuel was pretty steady under normal driving before the injectors. Since I installed them and that's the only thing I did the a/f seems to roam 11-15 without change in throttle position. Some days it acts normal and some it varies. It didn't do this with the stock injectors so my only guess is I need a fuel pressure regulator.?? Any ideas? Under full throttle the car holds a steady a/f. Separate question unrelated but a long time ago when the car was on stock turbo and boost I hooked the the Safc just because I was bored and used it for monitoring till I got mods and the knock reading was normal after start up. Drive for thirty minutes and the knock would read 140-150 but if you turn off the car but leave the ignition on and watch the sensor reading it still shows a reading of around 120 with the car off. So I need a new knock sensor correct? The problem still exists today and it's just bothersome to not know for sure. Thanks for any help

 

sounds like a bad knock sensor. a bad knock sensor will make the ecu do funny things. usually drown itself if gas since that usually makes the knock go away.
if you didn't tune it again after the injectors, then you are going to need to. a bigger injector will spray more fuel in the same cycle time.
it kind of depends on how you have your o2 sensor set up. I have seen some wide bands that replace the stock o2 sensor and send a signal to the ECU telling it that everything is perfect, regardless of how lean or rich it is, and others that only display the A/F and still let the ecu know if it is rich or lean.

then of course, you could have other stuff going on too, like a bad tps, a vacuum leak, burning oil, a maf sensor going bad....

 

I have an aem wideband so I didn't replace the o2 sensor. I tested the maf, tps, vacum, replaced plugs, i'm not burning oil. So it must be the knock sensor. Do you think the knock sensor could be cause it to spudder slightly between 3k and 4k under slight acceleration? I'm thinking one of the injectors may be going bad because when it does it the wideband bumps slightly closer to the lean side when it spudders. I hate to think that because the injectors are new from enjuku. (five -0). I'm replacing the knock ASAP

 

I noticed the car doesn't spudder if I drive it at night or when it's cold in the morning but if it's hot and the car is fully warmed up it will start. I pulled the fuel rail today to see if I had an injected o ring leak but it was all good. Still puzzling me..

 

sounds like a combination of knock and bad coolant temp sensor

might be getting the knock because of the bad coolant temp sensor, but since you said the knock sensor was bad, then I'm thinking the coolant temp is bad, causing it to run rich, the o2 sensor is seeing that, and it is trying to lean the mixture back out, which in the process is causing the knock because the engine is hotter than the ecu thinks it is.
that's my speculation at this point.

 

So the thermal sender(small one) or the big red one the coolant temp sensor? Just want to be sure before I replace it. I'm gonna do the knock sensor as well as soon as I can find one. It looks like its gonna be a pain.

 

Sounds like its misfiring. Misfires will show up as lean on the wideband. Assuming all sensors and such are working correctly, I would be looking for a weak link in the ignition system...check the plugs, coil pack specs, maybe the igniter..

As for the wideband jumping around...you need to work on your "tune" lol.

And for the knock sensor...what wire do you have hooked up to the SAFC for that? And what is the reading? 120 whats? lol. I know SAFC cant read knock on Mitsus and its about the same thing here I thought.

 

ummmm, on what planet does a miss lean your a/f out? If your car misses, that cylinder just didn't have complete combustion, so raw fuel goes into the exhaust tract and would show up as a richer mixture on a wideband. IMHO you will NEVER get an AFC "tune" to run optimal a/f ratios at all times.

 

Ummm its an o2 sensor, not a fuel sensor. No boom = extra o2.

 

yawn.