Lean spikes...

richiea · Post by **richiea** » Mon May 08, 2006 7:33 pm

I've got my car running pretty well right now with MS2 with tuning care of the LC1. I am however having lean spikes between shifts and whenever I blip the throttle quickly. At first I thought it was the TPS but I've checked it a few times and there is instant activity once I press the throttle open at all. Setup is a turbo Audi 5 cylinder and I am running a BOV.

I assume the two lean spikes are occuring for different reasons, but I'm wondering if someone could help me to tell me what to look into to fix both of the problems one at a time.

Thanks!

Stock · Post by **Stock** » Mon May 08, 2006 10:32 pm

sounds like you need more acceleration enrichment

richiea · Post by **richiea** » Tue May 09, 2006 5:30 am

Stock wrote:sounds like you need more acceleration enrichment

I assume acceleration enrichment would help for "blipping" but would that also help between shifts?

What value should I increase in megatune? the PW or the % and how much of a value do I need to change to notice a difference?

Thanks!

jonboyb · Post by **jonboyb** » Tue May 09, 2006 9:58 am

I will be watching this thread closely. I wish I had some advice for you on this issue, but unfortunately I have been battling the EXACT same issues from day 1 (2.6 liter Mitsu Turbo MSII/V3.0 with (4) 75lb injectors). A lean hiccup whenever I blip the throttle, and between shifts, which make gear changes brutal.

On another note, I have discovered that I have the same issues even with acceleration enhancement disabled, which leads me to believe the issue isn't in AE. That leads back to my VE table, which I have a significant amount of confidence in being correct. At this point, I starting to wonder if I need to adjust some of the lag averaging factors in the general setup screen, especially TPS, MAP, and RPM lag averaging.

Not trying to hijack your thread, just leting you know you're not alone

richiea · Post by **richiea** » Tue May 09, 2006 10:27 am

Interesting points, I didn't know much about lag settings, but that makes a lot of sense. My TPS initially was a little off, meaning I could depress the throttle approx 5% and it wouldn't register anything. The lean spikes seemed as if they were more frequent when the TPS was setup like that, but since then I have adjusted it and the realtime display shows perfect TPS functionality. However, when I review the datalogs (like below), I still see some alarmingly high spikes between shifts or at blips.

We can't be the only 2 out there with this problem!!!!

jonboyb · Post by **jonboyb** » Tue May 09, 2006 11:32 am

I plan to spend my evening focusing on these issues, and I'll post/PM you tomorrow with any results. As you mentioned earlier, I can tune out the throttle blip problem with careful tuning in AE, but it makes drivability even worse, so I'm moving away from relying on AE.

bluetrepidation · Post by **bluetrepidation** » Tue May 09, 2006 1:59 pm

I am getting lean blips too. AE works but with very quick snaps of the throttle I get a quick lean spot. I also noticed under load it doesn't seem to happen. I'm suspecting the high map/low rpm of my VE table is to blame since it is hard to tune there. When you snap the throttle this is the area of operation for a quick second. Just my thoughts so far.

A.J.

richiea · Post by **richiea** » Tue May 09, 2006 5:14 pm

Well I changed the TPSDOT number down to 1.2 and the accel period to 1.0s (as in the help) and the problem has decreased significantly, enough to make me feel fine about it and focus on tweaking the rest of my tables.

Now I'm curious as to why autotune isn't correcting enough! Anyhoo, I suggest to everyone to try those things if they haven't already! Thanks for the ideas!

jonboyb · Post by **jonboyb** » Wed May 10, 2006 2:56 am

Is your TPSDOT 1.2 v/s or 1.2 %/s? I'm not sure which Megatune you're running. I'm assuming its 1.2 v/s you're referring to.

I noticed last night that the rough shift seemed to occur when I shifted at lower RPM's so I rearranged my VE table to smaller RPM bins up to 3000. Certainly helped the shifting, but it's not eliminated yet. Ran out of battery on my laptop and had to end the night early

As far as autotune, how much authority have you given it in the EGO setup screen? Another tactic I've started using is modifing the custom.ini file to bracket certain areas I want Autotune to change, ie. 2200-2600 RPM and 60-100Kpa to try and massage the shift points. I usually give it pretty high authority, like 50%, when I do this, since it's difficult to hold the car in that range for long periods.

bluetrepidation · Post by **bluetrepidation** » Fri May 19, 2006 7:37 pm

You guys have any luck tuning out your AE? I'm still getting lean blips and I can't seem to pin it down. I found my max v/s for my TPS is 75 so I rearranged my bins accordingly. I also have my tpsDOT set to 1.5 to increase the sensitivity....

http://70.226.38.10/~admin/MS/AJs_Satur ... 190823.xls

At the end of this datalog I lightly rev the motor from idle and you can see where it goes dead lean on me. Almost like it isn't reacting fast enough or it isn't sensitive enough. I dunno I'm kind lost on this one now.

A.J.