My Actual AFR is running richer than commanded during serious track days and I'm trying to figure out my tune.

The EFILive guys gave me a list of things to check, starting with the B4001 Injector Flow Rate table.

I've researched like crazy about Injectors and have some understanding now.

Stock Z06 Injectors are rated at 28lb for 58psi 4bar. The spreadsheet defaults to 43.5psi 3bar because that is how most injectors are rated when sold.

So if I input a flow rate of 28 at a rated rate of 58, but then change my actual pressure to 68 which it is, I start seeing problems. This is assuming my injectors are still stock. ( I now know there should be a part number on the side of them, I'll get that when I get my glasses to read ) So I'm racing around and my commanded AFR is based on a 58psi table when actually I'm pushing out 68psi and more fuel. This explains why I'm running richer than commanded. Now if my injectors are upgraded bigger ones, that condition would be even worse to the rich side. The pcm is sending voltage to the injectors like they are small 28lb injectors at 58psi, but if they are big 40lb injectors being hit with 68psi, they will be releasing too much fuel.

Please confirm what I'm thinking that if this IFR table is too low, I'll be running richer than commanded?

Also please explain why the b4001 table and the injector.xls spreadsheet stop at map Kpa stops at 80. When I'm speeding along, my map gets close to 100 Kpa which is off the table? Is there another place for WOT IFR?

I'm learning as fast as I can, don't laugh too hard at that last question. I hear guys talking about how the WOT settings are less computer controlled all the time, I just don't know where to look inside EFILive yet.

 

CAN YOU SEND ME YOUR TUNE? cablebandit@comcast.net

I noticed that you are showing +25 ltfts at wot.....that indicates you have a part throttle problem somewhere. The +25ltfts indicates that at part throttle/cruise your tune is 25% too lean and the pcm is correcting this. It could be IFR.....could be something else...what aRE your mods?

 

Cablebandit, thanks for offering help. I did a BBL log from Road Atlanta and posted everything up for the EFILive guys. They noticed what you did and a bunch more ( see below ). I started going through their recommendations and hence the B4001 questions. I now know my injectors are stock 28lb and believe that most likely my gauge isn't reading right.

After torqing my FAST92 which had come loose down AGAIN, cleaing my MAF with MAF cleaner, and going thru the AutoVE procedure. My logs are reading pretty good today. Fuel trims way down, AFR is following commanded fairly way better. My idle problems are completely gone. Of course 80mph on freeway isn't 135 at road atlanta either. I do notice it detonates a bunch when I get on it and that can't be good even though the logs don't show any KR.

I'm not sure what my next step is and have a million questions. I'm thru the AutoVE and I suppose the AutoMAF is next per their instructions.



Originally Posted by joecar
Good log, very interesting... 43+ minutes...

Log shows:
- LTFT's ranging from +12% to +25% (pegging)... indicates MAF may be reading low,
- WOT: actual AFR is richer than commanded AFR by at least 1 AFR,
- WOT: actual AFR is going as low as 11.0,
- CL: actual AFR at stoichiometric equal to commanded AFR... indicates wideband is functioning,
- closed throttle: actual AFR spiking lean (is DFCO enabled...?),
- fairly consistent knock at WOT,
- injector duty cycle hitting 100%;
- there are a few places at WOT 6000+ RPM where MAF is well under 300 g/s;

I'm not sure, but I think maybe the MAF is dirty (only clean with MAF cleaner)... check the air cleaner filter also;

Maybe do this (in this order):
- recalculate B4001 IFR (even if to just sanity check it),
- redo the VE table (AutoVE, in OLSD) if you haven't already (get a log in OLSD anyway),
- correct MAF (using AutoMAF, in OLMAF with B0120 zeroed), get MAF ben to 1.00, get some logs;

Set high load areas in B3605 OL AFR and B3618 PE AFR to something like 12.6.

Once you get the actual AFR matching the commanded AFR, then your injector duty cycle will probably go down a bit.

Questions/Comments:
- you're NA so AFR 11.0 is a bit too rich;
- have you considered running a few laps in OLSD...?
- I don't believe the oil cooler will affect your IAT.
- why is knock being indicated...?
- check if motor ingesting oil thru PCV...?
- does engine top have carbon deposits (have you ever had top engine cleaner)...?
- how many miles on engine...?
- sawtooth pattern on KR indicates it may be real knock (especially during WOT pull);
- from frame 10006 ECT starts to show higher trend... why...?

Create some maps like the one attached to see if you can correlate KR to something.

My $0.02...

 

do you have ls1 or ls6? ls1 pcv sucks bigtime....might be pulling oil....especially when you are slowing fror a turn with the motor turning a lot of rpms. Oil will cause knock

 

Sorry about the old sig, I now have an 01 Z06, so LS6. Your concept applies though. My 01 z has a problem known as ring flutter. They actually have a recall on it for this. High RPM, low load (slowing down after striaght!) the scraper ring flutters and allows some oil up into the chamber and a puff of smoke. Its supposed to be bening to performance and only a "oil usage" problem.

 

the ls6 valley cover works pretty well but i do have a catchcan inline with mine. easy enough to pull the throttle body and look inside the intake with a flashlight to see if it seems really wet. Oil is very low octane and can cause knock. Main thing is to get those fuel trims inline though. My forced induction car runs a leaner afr than you are right now. I would guess you need to be in the 12.6-12.7 range since you are really getting the motor hot. Keep an eye on your coolant and oil temps. I assume you run an extra qt of oil at the track as well.

oh...you said it detonates but doesnt show it in the logs. Log it and look at your commanded timing vs actual when you think its detonating and see if they match. It could be burst knock which doesnt show up as knock retard i do believe. If your maf was that dirty, i would think some Seafoam would be in order to clean the tops of your pistons.

 

I have a catch can and oil filter breather. Catch can caught maybe 1 inch from two days of track. I checked my Tb and it was clean (rubbed with old sock, barely any black came back), vararam filter was clean too. I sprayed whole can of MAF Cleaner, but to the eye, didn't look any different.

 

See if you can see oil pooling on floor of intake manifold using a flashlight to peek past throttle body blade.

Knock sensors can fail over time... I don't know if this is your case.

 

what joecar said....throttlebody wont be oily like the floor of the intake will