NefMoto

Pretty sure this is my first post here on NefMoto so I'd like to start out by thanking Tony and others for all their contributions to this site.  Self tuning has been a long time goal of mine and I feel it's achievable because of the info here.  In December I pulled my 2.7T motor, swapped in a used one and added used K04s, new clutch, FW, O2 sensors and replaced a bunch of seals/gaskets, etc.  I've been reading a lot over the past month while I broke in the clutch and I'm all setup to tune.  I re-flashed my t-box with the stock m-box code and started playing around.  First I coded out my rear O2s and EGTs (one is bad) and monitored/tweaked my LTFTs on stock injectors for practice.

When I bought the used K04s they came with Siemens 630cc injectors and an 85mm MAF.  Today I installed the injectors as the first step.  I drove around for about 30 minutes with different types of load and a few WOT pulls.  Readings from block 32 were 2.4%, -6.3%, 2.8%, -7.0%.  This is with the values from Tony's base m-box with injector adjustment to KRKTE and TVUB. 

I know tweaks need to be made to lower the LTFTs but my main concern is I was getting a lot of misfires (25-75) at idle on one cylinder (plugs are new).  The rest of the cylinders were zero.  If I brought the RPMs up a bit the misfires subsided.  It looks like these injectors were flow tested at one point as four of them have 620 etched into  the body, another has 629 and the one with all of the misfires has 610.  So...

• I know these injectors have a reputation for being inconsistent.  Is what I'm experiencing par for the course with these?
• Should I look at replacing the 610cc injector on cylinder 4?
• Should I just raise the idle RPM and move on?
• Is it expected these misfires will go away as I continue adjusting KRKTE and TVUB?

I just don't want to move forward with tuning until I know I can trust the hardware.

Thanks,

-Roman

When I get home I will post the TVUB's I used when I ran the 630's.  For whatever reason, I had problems with Tony's values as well.

i have some very old 630s and I run stock tvub...

i hear the "older" ones are better, ymmv.

I seem to remember I was running stock or close to stock values.  I spent a lot of time screwing around with it because it had some stability issues just off idle.

OH also i still get occasional misfires at idle. can't get rid of them.

I guess I expected some misfires based on what people had said about these injectors so I was surprised that five of the six cylinders had zero misfires.  With the one marked 610 having so many misfires I'm not sure if this indicative of a hardware issue.  I have KRKTE set to 0.04673 and this morning I used Nehalem's spreadsheet to adjust TVUB to the following:

7.0400v       2.1217
10.0672v     1.1296
12.0384v     0.9216
14.0800v     0.8256
17.8816v     0.7296

I drove to lunch but didn't get a chance to log.  It felt like there were slightly less misfires.  I'll log on the way home tonight to see what is happening.  I just checked and those TVUB values are pretty close to what I started with stock.  I'll see how it looks and possibly try the stock values.


Guessing they aren't isolated to a single cylinder? Do you still have the idle speed set to stock?

Two problem cylinders (but only those two), and yes, idle speed is stock.

Have you tried swapping injectors around to see if the problem follows? Also worth checking coil packs they are renowned for causing mis fires even at idle, I would eliminate those first and then look at the maps

Here are the latencies I used with zero idle misfires:

(http://i.imgur.com/nvBYt.png)

YMMV of course.  KRKTE @ 0.04673

Stock injectors ran fine before the swap but it's easy enough to move a coil pack.  Similarly it's not too much work to move the injectors around as well.  If I get some time this weekend I might swap them around but I'm fairly certain I already know the outcome.

Thanks, Jason.  I went back to stock last night after it looked like I was running super rich.  I still need to check the LTFTs now that I've put some miles on it.  I am getting throttle cut with the stock values and I wasn't seeing that before.  I'll see how your numbers compare and continue adjusting. 

Really wish my cable supported Tony's licensing.  The full flash can feel like an eternity when you are in a rush.  Might be time to get a supported cable.

What does your idle torque reserve look like?

NLLM, KFMRES and KFMRESK are stock m-box values.  Aside from coding out the O2s, EGTs and enabling left foot braking I've only touched KRKTE and TVUB.

(http://i.imgur.com/w4B8B.png)

Stupid question: how does idle torque reserve work?

Page 52 from Greg Banish's book: Designing and Tuning High Performance Fuel Injected Systems states that;

 "At idle it is helpful to maintain a torque reserve to ensure that the engine can quickly respond to changes in resistance. By intentionally operating the engine with less than MBT timing, the ECU knows that it could increase the engines torque almost instantaneously by adjusting back toward MBT. The ECU can also instantantaneously retard timing to reduce engine torque in cases where less is needed for a brief period.. The gap between delivered ignition timing and actual MBT at idle represents the torque reserve that is held for unforseen changes in engine loading later on"

I just confirmed I was using stock KFMRES...  You can try bumping up KFMRES to dial out the occasional misfire.

With KRKTE set to 0.03508 and essentially stock TVUB values my LTFTs look pretty good.  I'm going to keep checking them but they eventually get down to less than 1%.  I was still getting 100+ misfires on cylinder 4 still so I copied over the KFMRES and KFMRESK values from the NefMoto v1.2 tune.  That nearly eliminated all of the misfires!  After the car was warmed up it idled with no misfires.  I'll monitor that as well and think about bumping up the idle to 800 or so as that is where it seems to want to sit. 

Are there negatives to using KFMRES and KFMRESK values further from stock?  I can try bringing them closer stock and find the sweet spot but it idles nice right now.

Thanks for the help!  Next step is installing the 85mm MAF and adjusting accordingly.

AH. And to maintain the same rpm with more reserve (worse timing), the throttle plate is open a bit more, at the cost of a touch of fuel efficiency to keep lambda 1?

Thanks, finally I understand torque reserve.

What are you guys using to detect misfires and read your ltft and stft. Before I just used an OBDII scanner but I do not own one and have not had to use the one at the auto part store since the nefmoto software came out but I dont think I can use that for reading the fuel trims. Or can I?
Thanks

I'm using VAG-COM to monitor LTFT (block 32) and misfires (blocks 14-16).  I'm not sure if the NefMoto software can be used to monitor.  I forget the name of it (ME7 Logger?) but there is a high sample rate logging tool someone developed and posted here.  I believe that could be used though I haven't tried it.        When it comes time to serious logging I'll probably use ECUx if only because I already have it setup and I'm familiar with it.

Take the time to configure and use ME7Logger guys. It's the kitten's pyjamas.

http://www.nefariousmotorsports.com/wiki/index.php/Main_Page#Software_Tools

That's what I assume, and your welcome.

As far as EcuX, put it in the recycle bin and move on. Me7logger with the GUI is too easy to use. I=retard when it comes to computers. I got it working without a hitch, and that means its really, really easy.

Ok, Ok... I'll check it out  :)