Bunker, in that case I too have the problem,I thought you guys were addressing a drivability concern, I thought the fumes were normal to a certain degree(no cat). But why did my blms stop rising after adding fuel?

 

I have a 260/260 solid roller cam....Joe Overton himself told me Closed Loop operation wasnt going to happen, but I tried anyway and failed. Altho I have heard cams as large as the 306 can run closed loop tunes but just smells rich at an idle.

I know for a fact my car smells almost of raw gas at its 1000 rpm idle and the Wideband says it has a 18:1 AFR.......lol dead wrong. Overlap sucks at an idle but is awesome at full throttle......especially on the spray

 

Do you want to try out my Closed loop tune? Maybe it'll work for you? I have a pretty nasty cam on a 109 LSA & no probs here.

Matt.

 

So either way that we run these, the o2's are still going to read wrong to actually what is going on in the cylinders, so the only thing that we can rely on is the ole spark plug reading method.

D Moss

 

thanks for the offer, but I have no MAF or O2's anymore

 

What you smell is a very high hydrocarbon count from being too lean...
18:1 afr ....ouch

 

OH NO... DEFINETELY NOT ON THE SPRAY.. you do not want your expensive N2O to get out of the chamber... when you have n2o you do not need air perse.

 

I can assure you its RICH not LEAN. Please tell me you are joking........

it registers 18:1 + which basically means due to the sensor being unable to accuratly read AFR at idle ( slow exhaust pulses ) it kinda goes off chart. a tip in the throttle and the AFR comes down the the 14s'. The real AFR is NOT 18:1 at an idle.

 

My lobe seperation is 112, not the BEST N/A cam and not the BEST N20 cam.....however I have dyno sheets that say it LOVES N20

please , no more telling me what I am doing wrong. Thankyou.

 

Do yourself a favor and put a sniffer in the exhaust and check the hydrocarbon counts.
I'm not joking...>>>no smiley here<<<
It will burn your eyes smell like its running rich the block learns will be maxed out [160]
160 means the ecm is adding max correction to fueltrim >>> running way too lean
108 means its making max correction taking fuel out >>> running way too rich

 

No at idle & mostly only at idle & really low rpm with big cams, 18:1 is ussually pretty good. The best way to check to see if your running rich or lean is with a Emissions sniffer at a shop, put it up to the sniffer & check for CO, you should have 1% CO ussually a good reading for fuel injected cars, higher is richer then normal, smaller number is leaner, CO isn't effected by overlap, CO is produced in the combustion chamber only, so even if you have fuel/oxygen escaping through exhaust the CO doesn't change since its only a product of your cobustion. Hope this helps.

BTW after carefull logging my idea didn't work, reason my idle got lots better is because if you don't let LTFT learn your idle becomes more consistant, if LTFT is maxed out at say 135 well it won't learn past that & at times the idle is more consistant, but it still runs rich because the STFT still add fuel, I thought the STFT just show you were you're at & the LTFT correct it to get the STFT back to 128, well I was wrong, if the STFT goes to say 150, its still correcting fuel because you can see when you come to a stock the o2s read low 100's & then after 5 seconds they start jumping around, so its still learning, in OPEN LOOP I'm getting 18:1 A/F & 100 for o2 readings & its were she runs real nice because the ratio in the combustion is acctually proper at that.

You see for some that don't get it, with overlap lots of fresh oxygen is being thrown out past the valves while idling & so does fuel, unfortunetly our O2 sensors & every other O2 sensor is just THAT, it only reads the O2 comming out, the extra fuel thats dumped past the overlap isn't picked up by the O2 sensors but the fresh oxygen is, so it tells you its lean while in reallity its fine if not too rich in the Combustion Chamber (actual useful fuel mixture), with stock cams barely any unburnt (unused) oxygen passes through the overlap because the duration/overlap/lift is so small barely any oxygen gets past the valves that doesn't get to participate in the actual BURN, so after combustion occurs the oxygen content is consumed & the o2's are calibrated for that to read proper A/F, when big cam comes in this goes out the window, now the only way to know if you're running a proper mixture is with an emissions tester & check your CO readings, aim for 1% at idle.


Matt.

 

incase you missed it, I run Speed Density mode with a wideband 02 setup.

I have no MAF or stock 02 sensors.....which means I have an open loop tune and there is no Closed Loop or learning occuring in my PCM.

Sorry Bunker, I didnt wanna burst your bubble but I went down that road before trying to get a closed loop tune.....and you see where I ended up.
Its a pain getting speed density dialed in but the wideband makes it easy and once its done you will be kicking yourself for messing with a MAF sensor and Closed Loop for so long

altho at the current moment I put my MAF back on because I wasnt done with my speed density tune and I blew a header gasket so the wideband is off. once I get my new headers from Jet Hot ( long story but its their fault i have blown 4 header gaskets in 8 months) I will be going back to finish up.


EDIT: I just thought of something bunker, what If you put the car in WOT mode at an idle ? This would disable your STFT's and editing the BLMs like u did would limit the LTFT's.

Another Idea is if you have the newest version of LT1 Edit you can lock your BLMS at 128 at WOT. by setting the PCM to see IDLE as a WOT mode you could actually disable all fuel learning this way, once the LTFTs are LOCKED at 128 and the STFTs are not used in WOT mode its not going to try and add/subtract fuel. and you can use the PE table to take out or add fueling at an idle.

 

Hehe Been there done that, I have the newest version of tunercat/LT1_edit version 2.2, tried the WOT PE table mode, fergot what it was but I coudn't get the car to run right, I think its cuz the PE table went in too big of RPM increments making it impossible to run right, I don't see why you didn't like the MAF though? I am definetly thinking of ditching the o2's but you need the MAF for a few things, see problem with running no MAF is atmospheric conditions will greatly affect your tune, its like in the old days people would tune their car but then in a month when it gets hot outside now they are running too rich, atleast with the MAF you don't run into this problem since if you get her tunned right the first time, & it gets hot outside the MAF will lean the mixture out, no need for o2s to take care of atmospheric changes, the hotter air causes the maf to register less AFGs leaning the mixture out, so you can get away without o2s & still be tuned near perfect durring all conditions.

Just a thought, why did you get rid of the maf?

matt.

 

well for couple of reasons
#1 its a restriction
#2 it doesnt allow me the fine tuning I can get by using the VE tables as the primary fuel controls.
#3 we believe its responsible for the choppy dyno graph and weird fueling issies at 6600-7000 RPM range.

Its also a myth that Speed Density mode cannot correct for weather differences. Granted its not as good as a MAF but it uses an equation with the IAT sensor to do some corrections. But I have a wideband setup and can do minor tuning for temp changes anyhow. A kid on here NASTY SS with a pretty hard core LT1 like my own turned me on to Speed Density and Wideband trust me, once you go Speed Density you never go back to the MAF.

 

I'm starting to think the same, care to share your VE tables with me ? I think I'm about fed up aswell.

Matt.