The reason for the long sting of zero's from the 02 sensor feedback is becuase on startup the car runs in open loop for a min or two so its working off of your fuel maps instead of the 02 sensor. I think +/- 12.5 are the max trims will go, and if there 12.5 for a long period of time, the CEL will come on with a lean or rich code! At idle my 02feedback at idle will be 0 for about 2 min (open loop on warmup) and then it starts reading and adjusting fuel in closed loop to achive around 14.7 AFR, I remember when my 02 sensor was bad from my blown turbo it was reading all the way up to +24.80, and stay there until i got into open loop. After i got a new front 02 sensor it doesnt go that high anymore and fluctuates correctly. Maybe you have to work on the scaling, or maybe the MAF sensor smoothing or compensation table? If its crusing ok but idleing rough, maybe you just need to make small adjustments to the MAF scaling or compensation?

 

Mitsu is correct. ltft max is +/-12.5 where stft max is +/-25.

Hornstar I suggest trying to rescale your injectors myself. You might have to revamp your fuel tables obviously but I think this is the best way.

 

I hope i dont have these troubles when i intall my 399 MAF

 

I gave up on the 399 MAF today. I've tried various things, stock lancer scaling+comp, evo scaling+comp, 501 scaling+comp, evo stuff but reducing idle hz comp.......nothing seems to work. The results I see are basically with stock evo settings everything is perfect except the car idles at 10-12AFR WHEN WARM...when cold, it idles 14.7. If i reduce Comp enough to make the car sit somewhere near 14.7, it still oscilates between 13-17, much wider and uglier idling than the lancer maf.

Anyhow, the old dude is back on the car, because I just am not having any luck getting it to run right. I even spent some time the other day talking to RoadSpike, and although some of the things he said made sense.....in the end, it still idles like **** with the 399 in there. The reason I don't think adjusting scaling or comp will be the solution for me and a 399 maf is because i see the same sort of stuff i saw on the base lancer rom, where afr's swing drastically....it just doesn't feel exactly right. Anyhow, probably selling the 399, saving for a omni map sensor, then a gm iat sensor, and then I might try my hand at speed density.....for now though, I'm focusing on getting a good solid 8psi tune as is. Oh, and adjusting the injector scaling did bring my trims down to a more acceptable range, it wasn't related to the 399 maf ...they just were off, but it's fixed now.

 

I'm having the same issue bro not sure why but I love 12-13 psi that's why I can't swap lol

 

WHOA!!!! hold the phone. I just realized something. You've got the evo MAF as well, and you're rich at idle. I thought it was your injectors or something, but then!!!!! I made a discovery.

So, the car runs fine at idle when cold, and the warmer it gets, the richer it gets. Anyhow, there is this table I was looking at, and I bet it could be the solution. I'll stick a pic up....anyhow, there are slight differences...who thinks what?

 

You know whats weird is I too have this problem BUT, it did not start until after I went forced open loop. Before that I have always had fluctuating afrs at idle but nothing with a pattern like now with the richer at warm idle. I tried early on in my tuning to tune out the fluctuating afrs but eventually gave up on it since near I could tell was not hurting anything, however now with this distinct pattern it really is annoying and I am almost positive it is what caused my egr valve to build up enough gunk to set the DTC. I might try adjusting that table andd see what I get.

 

I'm trying the same. Even with the stock lancer MAF, I still get fluctuations...they just aren't as "crazy" as with the EVO MAF. I may stick the numbers in the middle one into my car, and see how it runs with the stock MAF. IF it works, then I'll try the EVO again, but I bet the first is low octane and the second is higher octane....so I'll use the first in both of mine, since the lancer rom just seems to be really wonky when it comes to low/high octane, you know. Anyhow, yeah, I see the pattern as well...and this might be a relativly easy fix if it's as easy as copying lancer values in.

I think compensation and the compensation vs temp are specific to an engine, like....the same as volumetric efficiency and all that of an intake, so maybe we keep our comp, keep our comp vs temp, but use the size/filter/scaling of the evo MAF...testing will tell though.

 

Hrmmm.. mine idles n runs just fine with the 399.. But i am also forced closed loop due to sensors not liking my setup..
But knock knock(on my head) i dont tune.. i let my local master touringbubble do all his voodoo work on my car with his mystical powers..

only thing that ive noticed on mine is that it seems like after the cars warm, (id say Well past the warm threshold for a few mins) it tries to dial the idle down from 1100-900. I donno why. i normally only notice it like, after i get off the highway, or some other form of abuse where its abviously well beyond jus tbeing warm.

 

What are the AFRs like though during everything, always 14.7?

 

WOT mid/high11s... cruising.. 15-17. minimal throttle (accel without boost, less then 50% throttle)like.. 13s-15s. it all seems normal when driving it.

 

This kind of makes me wonder if I should lean my car out even a little more. I am hitting about 11.5-11.4 WOT then tapering down to around 11.0. I definately noticed a power increase throughout the rpm band after leaning it out from high 10's to the mid 11's I have now. I have the egt gauge to tell me if I am getting too hot and knock to tell if my timing is too high for the leaner fuel ratio, hmmmm...

 

11.5:1 RICH BEST TORQUE @ WOT

12.2:1 SAFE BEST POWER @ WOT

13.3:1 LEAN BEST TORQUE @ WOT

11.5-12.2 for turbo cars is the ideal range for WOT

And my lean cruise probably isnt accurate, its probably a smitch richer then that. Being that my exhaust is less then 3 feet long and the cam lopes hard, were pretty sure the exhaust sucks in air skewwing the reading a little.

 

im running around 11.5-12.0's my cel flashes around that point when running that lean. It took my car awhile to accept it but it doesnt flash as much as it did

 

I think the intake manifold has something to do with rich/lean conditions with respect to maf settings. Demon has a custom manifold, unlike most of ours, so maybe his works better with evo maf settings or whatevs. Still havent tested anything...too busy with work.