MAF and VE trims spiking -/+ 25 no matter what's changed..

[That_guy]

TUNES/LOGS ATTACHED AT BOTTOM!!

Would this indicate a possible vacuum leak? The car has a relatively small 224/232 114LSA cam in it(Zero degrees of overlap), and bucks/surges all over the place @ 1500-1800 rpms while cruising. I've done MAF and VE tuning and no matter how many changes are made, the STFT's are still pegging -20 through -25. On the MAF values, everything is going north to +10 through +18.

Should I start chasing a vacuum leak?

Thanks

[69lt1bird]

post your tune and a log file and all of the mods, what kind of car, which engine etc.

[That_guy]

2002 Fbody A4. Mods:
-224/232 114 cam
-Full bolt ons
-3000 stall
-Ported TB
-Stock LS6 intake

Tune is basically a stock tune 02 tune with some minor stuff done to get it to idle so I could do VE and MAF first. I'll post a log shortly. I'm thoroughly convinced there's an issue somewhere. Would MAP figures also indicate a vacuum leak?

[69lt1bird]

Well that's why we need the tune and log files, maybe you didn't tune the VE and MAF right.

[That_guy]

I'll get them up shortly.

The trims were spiking before the first correction was ever made. They were all in the -15 through -25 range before I ever touched VE. Then after 2 runs/corrections of copy/paste special/multiply %, nothing changed. They kept spiking. Then I switched over to MAF thinking maybe the narrow bands were just fubar, and the MAF values starting spiking posting 10-15, before changes were ever made.

[That_guy]

Ok here's the initial MAF tune, VE tune, 1st VE change (that didn't make a different in trims) and one log. All in that order. I goofed up and didn't save the other logs, but this log posted in a short idle log of the MAF and as you can see it's shooting up towards 14-18. VE logs were shooting up to -25 levels regardless of the first change.

And before anybody says "the MAF and VE tables are stock". No $hit. That's how the tunes were setup to start scanning. Once I saw the trims pegging, I didn't go any further until the problem was investigated.

Thanks

[umrjmac]

Do you have a log?

[That_guy]

Sorry, posted a config instead of log. I'll get a log up shortly when I get back to my tuning computer.

[69lt1bird]

Have you looked at the basics like do you have the correct fuel pressure at the rail?

[That_guy]

Yea just checked pressure at the rail, getting a strong 58-60psi. Went ahead and put new intake gaskets on, and a TB gasket. About to install brand new fresh NGK 02 sensors as well. Hopefully out of those 3 replacements I'll nab the problem. Once all is replaced I'll go do some logs, and report back with the logs if it hasn't cleared up.

[That_guy]

Ok, after gaskets/02's trims still aren't cooperating. Made one change, did a second log, trims are still pretty low compared to what I've normally seen. Advice would be great. thx

Attached below is the first VE change, then the log of the results. Trims didn't change much at all.

[00000D0101]

For the VE table, are you making changes to the secondary VE table?

[That_guy]

Ok, now I'm about to start throwing wrenches. I figured I could make a few runs/logs, make some adjustments, and trims would come down. Wrong, they've actually got worse in some areas. Now I'm showing -30 in some spots. How is this even possible?

Here's the latest VE tune, and VE log. Somebody throw me a bone here.

[That_guy]

....

[69lt1bird]

In detail, how are you tuning? Are you in open loop? I am guessing that you do not have a wideband, correct?

[That_guy]

Tuning in closed loop.

I do have a WB, but I can't find my serial cable to connect it to my HP interface at the moment. I also personally prefer NB over WB on tuning part throttle stuff.

I think I got the VE problem figured out.

Since you mentioned open/closed loop. Would tuning in open loop help with the car not holding an idle for $hit when you first crank it? Unless you let this car sit for a few seconds to warm up, it'll immediately die when thrown into gear while cold. I'm new to tuning the automatics for driveability so bare with me.

[69lt1bird]

Have you tuned the base running airflow?

The VE table in the tune you posted does not look very good to me. Looks like a huge cliff.

[That_guy]

Yea, that's the old one before I figured out my issue. I'll repost a new one after I get this one smoothed out a bit.

[That_guy]

Getting weird bucking in the 1400-1800 range. Trims have been smoothed out a lot, but my wideband is saying I'm getting a pretty heavy swing of 14.8-15.8 A/F in the 1000-2000 area. Idle is in the 15.2 A/F area.

Is the VE table the only place to control fueling? I need to have this buck smoothed out. This cam is extremely smooth with zero degrees of overlap, it barely even has a lope. It shouldn't be bucking at any rpm, especially with a converter.

Here's the latest VE tune. Trims are getting squared away, I've got everything in the usable driving range +/- 3-4%.

Thanks