|09-21-2012 09:36 PM|
we have fuel!
So the decreasing load and fueling issue is indeed directly related to setting the IMRC System Switch to "0".
This is what I changed (or not) in my tune to compensate for installing a new intake manifold with no flaps. You may be able to get away with leaving the spark tables alone, but personally I like to know exactly where the total spark value is coming from without guessing whether or not the PCM is actually adjusting for IMRC.
1) leave the System Switches\Scalar\IMRC Switch at "1"
2) Add the IMRC\Spark Adder to Borderline for IMRCs values to the Spark\Borderline Knock\Borderline Knock Table
3) Zero-out the IMRC\Spark Adder to Borderline for IMRCs values
4) Add the IMRC\Spark Adder to MBT Table for IMRCs values to Spark\MBT Spark\MBT Spark Table
5) Zero-out the IMRC\Spark Adder to MBT Table for IMRCs values
6) leave IMRC\IMRC Opening RPM as-is. This seems to no longer have an effect, as the "imrc open" flag is always "1" now in the logs, even at idle.
There are some tables under "Transient Fuel" which I did not touch.
I will update this thread if I feel there is anything else to add.
In closing, I will say that I DO NOT KNOW exactly why the PCM 1) negates the load calculation at the IMRC Open RPM position and 2) pulls fuel like crazy by setting the IMRC Switch to "0". Until I hear an explanation I am going to assume it is a bug in the SCT software.
|09-10-2012 08:30 PM|
|09-10-2012 02:59 PM|
Does the equation allow for you doing blowthrough and a MAFia ? You dont want to do a pre set equation you want to do load by what your load actually is
I can make changes and you can see what I chaged in the history and if you have questions just ask , I will answer them , call me I will talk over any questions
You can make the tuning easy or hard , most like to make it much harder then it has to be by reading into things more then whats needed , keep it simple , the engine in most cases will tell you what it wants / you need , if you are willing and know to look and listen to it
|09-10-2012 10:55 AM|
What I don't desire is a tune file back saying "try this" without an explanation of what you did and the purpose behind it. I know you and other tuners can fix this in a heartbeat, but there is no reason for me to own the Pro Racer Package if you do my tune for me.
I don't mean to come off angry, it's just that everyone is completely ignoring my original post. By the way I did find the equation for Load from Greg Banish and I'll post that up later.
|09-10-2012 10:41 AM|
I dont know why it is so hard for you to ask for help ? doing it here with steady logs and not seing the tune file is a waste of time and all speculation nothing more , guessing isnt going to help
I also agree you should never rev an engine to hit max MAF counts sitting still
|09-09-2012 09:23 PM|
I'm going to log voltage tomorrow to see if the value file I used for the 60lb injectors screwed up the injector pulsewidth offset.
I see that my previous setup with 55# injectors did not modify these voltage tables at all, and I had no fueling issues with those.
Any other suggested values to log regarding fuel are welcome.
I'm currently logging "fuel_rail_pr_psi", "fp_duty_cycle" and "ini_pressure_drop". For the record fuel pump duty cycle isn't going above 0.32, except at a rather odd time during decel when it hit .750 for a couple seconds.
|09-09-2012 08:38 PM|
You must be talking strictly about N/A engines, because there is NO way to hit 1023 MAF counts sitting idle with a turbo car, and you shouldn't. I think I might hit 300 free-revving like that.
Also, you do not fudge the base fuel table to get a desired AFR. The MTF does directly affect fueling. I'm not sure where you got that it doesn't. It is the primary table for the computer to know how much air is flowing (by what you told it) so it can use all other variables to produce the desired lambda set in the base fuel table.
There are many other factors you don't have to deal with being N/A. What I need is a full equation showing how load is produced so I can back-track across all my set variables to determine why the AFR is off. Most importantly I need to review my fueling settings with someone who has tuned a turbo car with these particular injectors.
|09-09-2012 05:10 PM|
You can't overcompensate with the MTF. That will reduce the fuel, and probably load.
That is step 1.
What's happening is that it's now harder to get to those flows and I'd bet you aren't hitting as high in maf counts as you should be. You should instead adjust the base fuel table.
I've read a bunch of posts, mostly self tuned Mustang guys, who say that to tune the MTF they do a log just sitting in their driveway revving the engine slowly up to about 500 counts and adjust vs STFT's from there.
Now while that is correct in part it isn't the full story. You can actually go all the way to 1023 counts by this method so long as you stay out of WOT.
The higher you can flow part throttle the better. What it does is makes it easier to get to the base fuel table, and therefore much easier to tune WOT fueling.
I'm just starting to use LL II to go through logs but man is it easy and quick once you have it setup right:
Set up the same as your counts, not mine
Gives you a easy way to see if things are working as they should. That is, are you using the base fuel table correctly or not. In this case I am.
You can open any previous log with Live Link II. You can't datalog with it though. For some reason it doesn't like the Focus and it also will only log with a XcalIII.
Download link --> http://www.focusfanatics.com/forum/showthread.php?t=290996
Or at least that's my take on it ...
|09-09-2012 03:56 PM|
Setup: 10psi GT2871r 2.0 Duratec, Cossie-type IM, 60lb injectors, 3" blow-through MAF, 50/50 meth injection.
I changed the intake manifold and injectors at the same time, so now I'm trying to troubleshoot two things at one time. What I'm seeing is the load DROPPING after about 690 MAF counts, and I'm clearly having fueling issues about that same spot.
AFR goes from about 11.0 and climbs to 14.0 where I let off.
Knock sensor is not pulling timing, but by the same token the total spark does NOT match the commanded spark in the BKT, but I can't figure out why the spark values are off.
Fuel source is 5 as expected and spark source is 2 also as expected.
The injector pressure drop is 36.99 and ends at 41.875 when I let off.
I clearly don't have the fueling set up correctly, but not sure where. It is as if it is ignoring the MTF after around 700 counts counts or so. I have the MTF quite over-compensated as you can see in the screen shot, with no affect.
I'm using the advertised injector values for these 60lb Seimens injectors and I've checked multiple places. I don't think the fuel is being properly scaled for the given psi, but need some help determining why.
The reason I asked for the formulas was so I can backtrack and see why the load is dropping instead of increasing and why the final spark value doesn't match what I'm commanding.
Screen shot of load falling off. This is at a steady 10-11psi, meth spraying.
Load - yellow
MAF counts - yellow
AFR - red
Fuel pressure - bottom line
Lots of other things logged but I'm not cluttering up the screen shot.
The over-compensating MTF
Displacement is stock and intake manifold volume is also stock. No MAFia.
Prior to the intake manifold and injectors the load would rise to 1.5 and fueling was no problem. The ONLY changes have been for the injectors and tweaking the MTF. Also the meth injection, but it does this regardless whether it sprays or not. Spraying drops the intake temps and the AFT around 1 point. I was spraying in this log. The leads me to believe the injector values are not correct.
Low slope (from value file)
High slope (from value file)
|09-09-2012 03:29 PM|
Post a log or something.
I don't quite understand what you mean by load is off.
I do know that adjusting engine displacement will change load. As will changing the "correction for max air charge".
But a log would really help.
|This thread has more than 10 replies. Click here to review the whole thread.|