Lean transition into PE and lean spot during WOT

[realcanuk]

The only thing I see in your tune that uses a fuel cut in in .. torque management.... general..... fast torque exit. I would try disabling this although I am not sure what it does since my tune doesn't have it. I wouldn't use a fuel cut anywhere since the last thing you want is lean spikes. The spark cut alone should do the job.

[Niemer]

I saw it right after I posted, I disabled both fuel and spark cut as well as brake torque reduction to see if any of that is causing my issue. I'm also logging the Fuel TqMgt pid to see what that says.

[Niemer]

Doesn't seem to have done anything in that area.

[Niemer]

I still don't have an explanation for the little blip 2 seconds after PE is commanded, there are a couple of things I have noticed throughout all the logs, it always happens 2.1 seconds after PE is commanded, I have never seen KR at that point that was obviously attributed to that condition, I have a log that shows the blip in a part throttle PE condition at a fairly constant MAF frequency, it happens right in the middle and everywhere else at that frequency is dead on commanded lambda. Cells 26800-26900 and 31527-31900 are the areas I'm talking about.

Attachment 40191

[FASSTRUK]

Is Dod enabled?? it shows up in your scan...it may be the reason for your "blip".

[Niemer]

It happens regardless of DOD being enabled or disabled.

[SultanHassanMasTuning]

check your transient fuel
MAP .2500 is stock

what do you have yours?

[Niemer]

Mine is at .2500, the help file doesn't explain any of the tables or values in the e38 apparently, so I'm really not sure what any of it does. I did make some changes to the enable delay, warmup transient fuel, evap factor blend, and transient fuel mass gain impact factor tables based on another guy's tune that had pretty much the same setup as I have, but they didn't make any drastic changes that I noticed. Current tune is attached.

[Niemer]

Could anything in the injector tables be causing this?

[realcanuk]

I run the same injectors. The only thing I see different that I have done is fill the "offset vs volts vs map" table using data from ID's website. I suppose you could try that although I don't know if it could make a difference for you issue. Looking at the last log you posted there seems to be KR all over. Personally I don't like to see any in my logs.
I would lower the PE enable (I use 83) and raise the enrichment ramp in. (try 1.7)
If you cant solve that random lean spike I would consider going backwards a bit and setting all the transients back to stock, tuning the VE (run blended) and see if that helps that problem.

[Niemer]

My next step was going to be tuning VE, just reading up on how to get that accomplished. My injector MAP offset table doesn't exactly match any of the tables in the ID spreadsheet, but I believe that one of them is similar, just uses "manifold vacuum" rather than absolute pressures. Is your offset select set to MAP or Vacuum? I believe a lot of the KR is coming from DOD activating and deactivating in that tune, it hardly shows up when I have it disabled, I have pulled back timing in those areas a bit already, looks like I'll just have to do more.

[Niemer]

I built up the injector MAP offset table and tried that with the offset select set to MAP and Vacuum to no effect. I have started tuning VE using EQ <> VE v4 and the blip 2 seconds after PE is commanded is still there. This is in open loop VE, MAF is failed, and it happens in very different areas of the table. I had set all the transients back to stock before I started with VE.

Things I have noticed:
Fuel pressure looks stable, it does dip a couple of psi on average entering PE with high engine load, but it remains constant.
There is no corresponding change in the injector pulse widths.
Again, always 2 seconds after PE is commanded.

[Niemer]

Update: I flatlined the stoich AFR table and the PE EQ ratio (Alcohol) table at the values I always want to see and logged a run. I still got the blip in PE at part throttle, but at WOT I didn't see it. One thing that happened during this run that I don't think has happened in any of my previous logs is that after I went WOT the trans downshifted from 3rd to 2nd, that may or may not have something to do with it. I plan on logging another run tomorrow with and without a downshift to see what happens.

Part throttle PE starts at frame 32930 and WOT at frame 42206. I know it's rich in PE, I'm still working on the VVE equations in the high MAP/RPM cells.

[Niemer]

It happened again after a downshift in PE where it didn't happen yesterday.

I'm probably going to put the stock injectors back in and go back to the last known good tune to see if it's the pump or injectors causing the issue.

[DSteck]

I can't believe nobody mentioned the fact that the injector data isn't set up right.

The VaporWorx system mimics a boost referenced fuel system. Because of this, you can't just plug and play the data from ID's spread sheet. The working pressure is always 58psi, so you have to flatline the IFR table with 58 psi fuel pressure flow, and also make the offset table flat according to pressure (it should still vary with voltage).

That lean dip you're seeing is because of that fuel system. I've seen it do it on multiple cars.



I've fixed your fuel injector data. You'll have to start over on the MAF and VE.

[Niemer]

I have the constant pressure version, not the 1:1, there is no MAP reference going back to the controller. Do I still set it up this way even though my rail pressure doesn't change with vacuum/boost?

[Niemer]

I swapped the stock injectors back in and loaded the last known tune that didn't have the issue and the problem has seem to have disappeared. After I got the FPS signal cleaned up a bit I was noticing a pressure spike right before the lean event, could one or more injectors be shutting off for some reason, some how? I purchased them brand new but could one be sticky? I'd really like to run them.

[Niemer]

I took a look at the stock injector settings again and I'm a little confused about how it is set up. It's almost like it is a hybrid between a constant pressure and a boost/vac referenced fuel system. Is this how I need to set up my tables?

[Niemer]

I've been working with ID on this and still have no resolution, anyone else think of something?

[DSteck]

I'd bet a ridiculous sum of money you're getting a very short burst of fuel pressure. A fuel pressure sending unit (and the logging data rate) is going to be too slow to show it.