E36 breaking up below 2000 RPMs

[Greenday694]

I believe I have my high-revving startup problem worked out. So now on to the other problem I have had ever since putting in link G4 Plus.

  Cold or hot, my car bucks sometimes violently at slight throttle below 2000 RPMs and below 10 psia. If I accelerate a little harder it clears up or if I Stay above 2000 RPMs. It will do this at 1950 RPMs. But as soon as I hit 2000, it runs perfect. I tried adding and subtracting fuel. And advancing and retarding timing. While its doing it the RPMs jump back and forth radically, on my laptop.

 Thanks for any help

[Adamw]

Log and Map please.

https://www.youtube.com/watch?v=_P1LRANeO4A

 

[Greenday694]

Not sure if I have the logger set up right. But this is what I logged. I'm trying to get it dyno tuned, unfortunately, the only shops around me that will touch a BMW, will only tune late model obd2. And all American and Japanese.   

I was wrong in my earlier post. It is the timing that jumps between -6 and +21 when its bucking.

Thanks for any suggestions on how to get this running better.

Log 2018-11-23 4;38;59 pm.llg

3L_M50_60lb_m122h.pclr

[Adamw]

43 minutes ago, Greenday694 said:

Not sure if I have the logger set up right. But this is what I logged.

Did you watch the video?  You havent clicked "add all" so you havent recorded much that is useful.  If I were to hazard a guess I would say it is your overrun fuel cut too active.  Turn it off and see it it helps.  Otherwise, please watch the video again and follow all steps.

[Greenday694]

I added all and logged another run. This time with overrun off. Still doing the same thing. It seams to be timing related. Under 10 btdc ? Like its still running on the idle map.

3L_M50_60lb_m122h.pclr

Breaking up below 2000 rpm.llg

[Adamw]

I dont see anything obvious after a quick look.  I think it will be worth doing a triggerscope (just at idle will do) to confirm there are no problems there.

 

5 hours ago, Greenday694 said:

It seams to be timing related. Under 10 btdc ? Like its still running on the idle map.

You have 14.5 deg in the ignition table 1, -1 IAT trim, and -5 from traction control (suggest you turn off traction control since you dont have a non-driven wheel speed).  

[Greenday694]

I turned off TC. No change. Here is trigger scope.

Thanks

[Adamw]

Ok, trigger scope looks good.  I dont see any anything else obvious however I would start by turning off the whole lot of the extra tables you have enabled just to eliminate an odd value hiding in one of them somewhere.

So as a test, turn off the six individual ignition trim tables, the 6 injector trim tables, the knock control, the transient retard, the 2nd fuel and ign tables, and turn off the VVT.  Go back to a basic, simple config and get it running ok first, then you can enable this stuff once the problem is known.

[Greenday694]

Okay back again. I turned off everything. Went back to the bare necessities. Open loop on fuel and timing. Vanos variable valve timing off. Idle control off. but still cutting out at slight throttle between 1500 and 2000 RPMs. I also tried increasing the values in the injector dead time while reducing a fuel map. Past experience with emulator tuning Bosch 413 and 506 ecu's, I've learned that they become very unstable when entering such low values needed for 60% or larger injectors. Apparently that is not the case with the G4.

  This started as a base tune that I received from the supplier I bought the link G4 plus from. So there might be some things active that I'm unaware of. The first thing I question about the tune is that it is for a m-52. My engine is an M50 with M54 B30 rotating assembly. I was told that the m-52 calibration file is a smoother transition between tables 1 and 2 Fuel and ignition. The M50 as I know, switches from one to the other once the Vanos Solenoid is activated or deactivated. based on engine load and RPM. The m-52 Blends the tables ,transitioning from one to the other based on actual cam position.

  This sounds like a good idea, but not sure if it will work with my M50b25tu cam profile.?

   Any other suggestions would be greatly appreciated.

[Greenday694]

I think I'm onto something? When I first looked at the base map, something did not look right with the VVT/ Vanos control. It did not become active until at least 40% throttle and above 2000 RPM's. The Vanos should start advancing the cam just off idle and fairly little throttle (2.1 engine load), and hold to about 4500 RPMs.

So after changing the X & Y axis, I have the Vanos switching on at 12% throttle and above 1500 RPMs. That made it about 95% better. I still have a few little glitches. But nothing like it was. Now I have to make some adjustments to the table 2 fuel map, because it's active a lot sooner. And I might lower the RPM trigger a little more.

  Is it possible to use the map input instead of the TP for the VVT control? And lock out the VVT below a set TP? 

Thanks, Keith

[Shedley]

Why you activate a second fuel table when vanos activates, it always activates on the same point/condition, so I would not know why you need that second one... 

[Greenday694]

Because it requires a slightly different fuel mapping with the intake cam advance. And it works better with the more aggressive ignition map.

Even though the ECU does a great job at adjusting to maintain my set AFR. I help it by setting the fuel tables as close as possible, so there is less searching, by tuning each fuel table in open loop first.

  This makes for  very smooth, linear Power from idle to redline. What BMW engines are known for. And it works very well on the track.

[Shedley]

58 minutes ago, Greenday694 said:

Because it requires a slightly different fuel mapping with the intake cam advance. And it works better with the more aggressive ignition map.

Even though the ECU does a great job at adjusting to maintain my set AFR. I help it by setting the fuel tables as close as possible, so there is less searching, by tuning each fuel table in open loop first.

  This makes for  very smooth, linear Power from idle to redline. What BMW engines are known for. And it works very well on the track.

I'll tell you something: I've more then 5 customers running on a fury écu on a s54 engine with dual vanos. Vanos always active, even on idle. Afr spot on, nice flat torque curve between 365-400 nm and 365-410 hp (some stock engines, some build with 302/296 cams ect) all on 1 fuel map strategy. Your vvt maps decide the position off your cams, so if load axis of vvt and fuel map are the same, there is definitely not a need for a second fuel map. As you have a m50 with a simply on-off vanos, thing getting even more straight forward. You're making it yourself way to hard. 

Have done m52b25tu engine ass well, on another ecu brand, same story. 

Make it yourself easy, ditch that second fuel map, let your vanos switch at a certain rpm (which you can easy test on the dyno) and if you choose to let it switch on a certain tp as well then set your load axis to tp as well of the fuel map, otherwise you make things complicate for yourself

[Greenday694]

I completely agree with you. Running my car on a dyno or on the track all I would need is one 1 fuel map. But my car is a daily driver back and forth to work stores everywhere. Sometimes stuck in traffic and never getting above 2000 RPM's. And these very low engine load situations the engine prefers a slightly leaner fuel map. Helps to maintain a very steady idle, and very low engine load. Crawling in 3rd gear at 1200 RPMs.

  I'm trying to achieve perfection. I want my car to run and drive as if it were brand new completely stock, until I really step on it and Force 16 lb of boost into the intake. Right now my 1\4 throttle to wide open throttle is very strong and almost perfect. With a 315 LSD, I can burn the 255/ 18 in second gear from 1000 rpms just by pushing the pedal to the floor. The low and mid-range torque is there, and top and horsepower. Low_end  driveability needs work.

  I will try to run a single fuel map strategy again. Can easily keep lower manifold pressure and RPM portion of map 1, then cut and paste the higher regions from map 2.

[Shedley]

What I should do personally is: set load equation to map. Then set fuel table 1 to load axis tps, and map the car on waste gate pressure. Then ad boost and set up an 4d map with load axis map, to take the fine tunings in account were the map calculation does not fix the complete calculation. To have nice and steady afr's. Ditch that fuel map 2 and set up your lambda target table to map VS rpm, problem solved, you can make the afr leaner on low load(map) conditiond

[Greenday694]

Do you have an m-52 map with this setup in it that I can look at and compared to mine? So I can get some idea of what it should look like. I'm still fairly new to this type of tuning especially speed density. Most of my experience is with Factory Mas based ecu's.

[Greenday694]

Figured I would give a little update to help out other people. My low RPM bucking problem is solved. In my idle speed control settings, the tune I started with had RPM lockout set at 1200 RPMs. I did lower this a little at first. Didn't seem to make much of a difference. Then I learned that this is not the actual engine RPMs. It is the RPMs above my base idle setting of 800. 1200 + 800 equals 2000. So Below 2000 RPMs but ECU was switching back and forth between the idle map and the main map. I changed RPM lockout to 300 RPMs, and it runs a lot better. I might bring it down a little more and see what happens.

[Adamw]

10 hours ago, Greenday694 said:

I started with had RPM lockout set at 1200 RPMs. I did lower this a little at first. Didn't seem to make much of a difference. Then I learned that this is not the actual engine RPMs. It is the RPMs above my base idle setting of 800. 1200 + 800 equals 2000. So Below 2000 RPMs but ECU was switching back and forth between the idle map and the main map.

I think you have that wrong.  In the idle ignition control section the RPM lockout is actual engine RPM.  Only in the Idle Speed Control section the RPM lockout is an addition to the target Idle speed.

[Greenday694]

12 hours ago, Greenday694 said:

Figured I would give a little update to help out other people. My low RPM bucking problem is solved. In my idle speed control settings, the tune I started with had RPM lockout set at 1200 RPMs. I did lower this a little

Yes, idle speed control

[Adamw]

So what are you talking about when you say it is “switching back and forth between the idle map and main map”?  What maps are you talking about?  The idle speed control rpm lockout just affects the rpm that the idle valve try’s to take control from.

[Greenday694]

Maybe I'm Wrong about what solve my problem then? When it was set at 1200 RPMs, and I was running the engine below 2000 it would buck and jerk sometimes violently and the ignition timing was jumping all over the place. Once I lowered it to 300 RPMs everything was smooth.