Accel and Decel trouble shooting

[grover]

Hi guys. I've had MS in my car for about a year, but honestly haven't tinkered with it at all for about 10 months. I basically got it so it ran decent (albeit VERY rich) but now I'm trying to get back on the horse and really get it dialed in. I know I need to address things one item at a time, and the area I'm trying to focus on right now is getting the AFR's better during accel and decel. My attached datalog illustrates that during initial acceleration and deceleration, I'm going quite rich. While some of this I may be able to render through the VE table, I've found that if I go much lighter on the VE in some of these bins (say 2500 rpm and 20-30 kPa) I get mis-fires while cruising. Also on my log, I see no action taken whatsoever by the Accel Enrichment, but quite a bit of action by XTau. So my question is this: where should I be looking to address these rich areas? Do I just have Accel Wizard so mis-set that it's not even coming in to play? Thanks so much in advance.

Some particulars on my set-up: MSII with 2.88. The car is a '73 BMW 2002 with a 2.3 liter bottom end from an early BMW M3, 9.5CR, 292 cam, and a ported and polished E12 SOHC 2-valve head.

[devastator]

So my question is this: where should I be looking to address these rich areas?

The VE table.
Your VE table must be dialed in very closely in order for Accel to work properly. How are you tuning your VE table?

I've found that if I go much lighter on the VE in some of these bins (say 2500 rpm and 20-30 kPa) I get mis-fires while cruising.

How much lighter are you going when this happens?

Also on my log, I see no action taken whatsoever by the Accel Enrichment, but quite a bit of action by XTau.

Under General settings you have x-tau for your accel/decel only. The accel wizard is showing a threshold of 20 and the tpsdot never gets over 10, so the accel will not trigger at these settings, unless you really stomp on it. I don't know enough about x-tau to help you with those settings, sorry.

[grover]

Thanks for the input. In terms of how I'm modifying my VE table, I'm using a combination of MegaLog Viewer, and more manual analysis for the datalogs in Excel. For lower MAP/rpm areas of my VE table, the recommendations out of MegaLog Viewer tend to yield VE's that are so low that I get mis-fires during cruising. Perhaps I could be running more advance to counter this, but I've had little success here. As such, I'm using some of the MegaLog Viewer recommendations in the higher MAP areas, but balancing this with analyzing the Excel Logs and seat-of-the-pants feel for the lower MAP (cruising) areas. And as for how much adjustment I'm doing in the VE tables, in the lower MAP areas I'm down to changes of 1 or 2%, not larger, I really think I'm super close to where it "needs" to be other than in the higher MAP/rpm bins where I've just not spent as much time tuning.

Would you still argue that my changes (for decel in particular) need to happen in the VE bins, or is there another way I can lean it out a bit on decel without impacting my cruising VE's?

[devastator]

Misfires during cruise are usually caused by running lean, but the datalog shows you running rich most of the time. Are you certain the WBO2 is reading correctly?

Would you still argue that my changes (for decel in particular) need to happen in the VE bins, or is there another way I can lean it out a bit on decel without impacting my cruising VE's?

You can change the decel amount in the accel wizard. Again, I do not know how x-tau handles accel or decel.

[grover]

Thanks again. In terms of mis-fires at cruise, the datalog I posted had only one or two I believe and they were where I was running a little lean. I made some adjustments last night to the VE and at least today that seems to be resolved.

In terms of the decel in Accel Wizard, would this be illustrated somewhere in the datalogs? I have it set at 90% right now for decel, but can't see which column in the datalog would show that it's fueling at less than 100% during decel? Basically, I can't see an indication that Accel Wizard is having an impact on decel one way or another. Is it "working" and I'm just not seeing it in the log? Am I just looking in the wrong place perhaps? Thanks again, your input is genuinely appreciated.

[devastator]

The decel light in MLV, (lower right corner of the display), will flash on when decel is active. You can also set one of the unused graphs to display tpsdot and watch the graph drop far enough below zero to trigger decel. Not sure if tpsdot will indicate anything with x-tau controlling decel, but I did see the decel indicator come on when reviewing your log.