On my 95' fbody my wideband reads 11.6 afr under wot. I went in tuner cats and changed my numbers in the afr vs. Rpm wot from -27.2 to now -44.9 still reads 11.6 afr at wot. What am I doing wrong?

 

I'm a little confused on your numbers to alter the AFR as none of the stock table entries have '-27' or negative values in them). The formula is " WOT AFR = 14.7 / (1 + %Change vs Cool/100 + %Change vs RPM/100) ". Using the stock table entries for the Coolant at 80* C - 220* C (180-220* F) and RPM 5200-5600. The calculation is 14.7/ (1 + 15.6/100 + 9.8/100). or 14.7/(1 + .156 + .098 ) or finally 4.7/1.254 = 11.722 AFR. So your 11.6 is near stock for that RPM range. For a lower RPM range you would have to use the applicable RPM entry in the RPM table. What RPM range and AFR are you shooting for, we can throw you some numbers to try.

 

I have an excel spreadsheet that will do all the calcs for you based on what you enter into the tables. I could send you an email of it if you want.

And I agree with bobdec, what you are saying doesn't make much sense. There is more than 1 entry that determines PE WOT A/F ratio for the 94-95 LT1 PCM. You will need to make more changes than just 1 entry to modify the ratio.

 

DOOM.. I'd like a copy of the spread sheet PM'd you w/my email address.. Bob D.

 

Ok my previous tuner cat table in the afr vs rpm wot was -27 from the rpm 2800-6800. I took the car out did a 3rd gear pull, my wide band said 11.6 through out the rpm band. So I went into tuner cats in the afr vs. Rpm wot table changed -27 to -32 to try and lean it out. Did nothing, so I changed -32 to -45 through out the rpm band. Still reads afr 11.6 on wideband. My email is scott_vershum@hotmail.com for that spread sheet. I believe on the afr vs coolant wot table my numbers are 12 for 80c.

 

Your numbers are really different than normal... I use your numbers 14.7/(1 +12/100 + -27/100) = 14.7/(1+.12-.27) = 14.7/.85 = 17.29 AFR which is way lean. Below is a pic of the stock tables. When you start putting '-' numbers into the table you actually start leaning out the AFR. In any case something is not working when you change the numbers. Either the PCM is ignoring your input or something is preventing entering PE. Do you have TTS DataMaster or a scanner that displays the PE mode status indicator.

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I do have tts datamaster. That's why my (-) numbers are so high, im trying to lean it out from the current afr of 11.6. But its having no affect. I know my 02 sensors are turned off currently. Would that affect going into pe mode? Ill use datamaster on it and see what it says.

 

Running open loop should not effect PE mode fueling changes. Are you open loop MAF or Open loop Speed Density (SD) ?? You can get DataMaster $EE download free for 20 logs or something like that. Get it cranked up and post up a log on a file sharing site so we can take a look.. By the way what AFR are you shooting for during WOT ?? Why open loop, what are your mods ??

 

Its open loop maf. Its a 383 lt4 with a 245/253 .612/.612 cam, le3 heads and all the supporting mods. The cam overlap is what me run it in open loop. It was Dyno tuned last year, but have changed a few things. I was looking to go, 12.8-13.0 on motor and with Nitrous where ever is optimal. Ill try and log it in a bit.

 

Im having trouble with datamaster. Its not even showing readings when the car is running.

 

You should have it shortly. Sorry it took a while to respond, seems like work takes up way to much time of mine these days.

 

Doom, got the sheet .. Thanks

Meen95Z.. did not realize you had those MODs. I usually don't mess with tunes done by tuners especially if they did it dynamically with a dyno and wideband. You can beat that for the best way to get it right. If you were happy with the tune I would get back and see about why his AFR settings are not working. I was wanting to see how the AFR is running in non-WOT running. But if you are running open loop DataMaster won't show meaningful AFR, or BLM info, only way to tune or work problems would be with the wideband readings. W/O a dyno it's a PITA.. requires tweak w/TunerCat, road test-log w/DataMaster and wideband and then repeat till correct.
Back to DataMaster, what Operating System are you running and have you set up the correct COM port. Since TunerCat works the problem has to be the software or the setup.. What is your failure indication.

 

Well last night I used the spread sheet to set up my tables to more realistic values. Took it out warmed it up and at wot, still 11.8. So went back changed the tables by -5 increment. Took it out still 11.8-11.9 wot. For some reason it doesn't wanna change the afr. I was at -12 at the most and same afr as it was at -27. Part throttle its 12.8-13.0. Idles at 13.9-14.2. Datamaster opens detects Pcm, just no readings are shown when its running on the screen. Im using xp too.

 

What should the (map kpa threshold be for wot) ?

 

Is TC locking the trims to 128? If not you may be using the EE definition file and should have them send you the EEL version. Otherwise, if your pcm is adding fuel when you go WOT, your fuel adjustments may not have the desired effect.