Hey guys, small problem on the new tune for the 406 with the 6E 165, got the idle going pretty good, everything seems to be running well, still tweaking the AE, but hey, on a motor this modified I know it'll take some time. Anyway runs great cruising down the road at light throttle but after the tranny upshifts the WB goes extremely lean for a few seconds, sometimes 20+ on the WB (man I love the ability to pipe that into the autoprom thanks Craig O-meter works great too) and the car stumbles pretty hard until the closed loop pulls it back into line, int's go way lean for the time period then come back into line slowly as well. Anyway I know somewhere I've come across the answer to this before, but my way tired brain isn't coming up with the answer, and my searches didn't find anything either. And I've been staring at Tunerpro way to much lately, it's all starting to blur together. Anyone got ideas or come across this? I'm sure I'm overlooking something way obvious, so be gentle with me . Thanks
John

 

I'm no expert, but I'd increase your MAP AE a bit to start with. See if that improves your condition at all.
How's your BLMs when you're not shifting? Sticking near 128?

 

The car does not have a MAP, it has a MAF. I would say to increase the AE, but it really wouldn't do too much on an automatic as the throttle is sitting at a steady position when the transmission shifts.

Rhuarc31-

Do you by chance have a datalog and the .BIN being used for your car? I highly recomeend looking at the log and correcting the MAF tables based on your BLM and wideband values.

What happens is the car will be running at say 2,800 rpm, 45 gm/sec and a BLM of say 115. The transmission upshifts, the load on the engine stays the same, but the RPM drops. The rpm drops to 1,800 and the MAF drops to say 35 gm/sec, but the BLM is still at 115. Now as the ECM sees that the mixture is too lean, it will richen up the fuel deliver with longer pulsewidths. Lets say that eventually (not more than about 5 secs) the BLMs will settle to say 140ish. For that 5 second period while the BLM number shifted from removing fuel to adding fuel, the car was very lean and hesitant. Once you correct the MAF tables, the BLMs will stay right around 128 and the car will pull through the shifts much nicer.

 

Is the car in P/E (and open loop) and then back into closed loop? Or always in closed loop?

My one suggestion, do a few runs in open loop - make your changes. And then run it back in closed loop and see the differences. This is definitely when you wish you had a MAP sensor with the MAF.

However, you do have the throttle position (which is how it computes the LV8) Maybe you can use this to help differentiate?

Sounds like it's time to do a "special version" of the $6E. But try do some tuning in open loop, adjust the Scalar Tables and then see how it runs in closed loop (overall) ... or try running in open loop if it runs better.

Lots of SD guys run in open loop, but it seem MAF guys are reluctant to try open loop.

 

MAF systems with a MAP do run great, lol. No LV8 calculation to worry about and plenty of MAP AE.

Open loop might work as well, IF the MAF tables are set properly.

 

The idea of running the MAF in open loop is to get them tuned properly with a WideBand. The more "real world" driving situations, the better the tables. Then I accept the tables as being accurate and the NB in closed loop being inaccurate. At that point, I find the engine runs better just by leaving it in Open Loop all the time then. I realize your setup is a litte different, but you should give it a try. It's a little time consuming to setup the tables, but I thnk it's time well invested.

Of course, no matter how much you test & tune, there will always be some scenerios that are virtually impossible to test (eg operating in temps colder than -20F and temps higher than +110F).

Or, decelerating in a high gear down a long steep grade for a number of miles. I know for a fact that the ECM drops out of closed loop for both MAF & MAP under that scenerio.

 

Thanks guys. After some sleep, food, a little looking at the logs and reading your replies, and a couple more tests, I think I've got it figured out. First is that both of ya are right plus another issue. I was doing both closed loop and open loop testing grim, attempting to get it dialed in with the WB first, as I've seen you say many times The problem did get worse if I enabled closed loop, and looking back at the logs it was similar to what you said Fast355, once I could focus my eyes on 'em anyway.

In addition though, just like I've preached many times, check the mechanical crap first. Had 2 other problems as well. First was a small exhaust leak at right by the O2 sensor, switched to a copper gasket this morning and seem to have fixed that. The other was that the freaking replacement pressure regulator I got from holley for the stealthram, which seemed to be working fine when I first replaced it has taken a dump and is now got wierd fluctuations worse than the first one. And of course I didn't think of it because I knew I just replaced the damn thing. Hook up the pressure gauge and go for a run and guess what. When the car shifts the fuel pressure spikes DOWN almost 10 lbs. Freakin holley, I love the stealth ram, but that regulator is crap. Wish I'd seen the stuff on the alternate intake board about it before. Anyway now that I've searched, guess I'll give in and buy the Kirban one. Anyway, put the old one back in for now, and while it fluctuates, its nowhere near as bad. The problems still there, but no where near as bad, close enough now that I feel like I can drive it and tune it out without risking hurting something, though I'll probably wait on the new regulator just to be safe.

anyway, you guys were right, and it was made to the point it was by the addition of the mechanical problems.
Thanks for the quick replies guys, really appreciate the help.