Lean Startups-Ve issues?

[mikeyv]

I've got a 2000 Camaro, 226/230-112 cam, ported heads and I'm trying to tune the ve table-open loop sd, but everytime I start the car the afr at idle will be 14.7 for about a second then just shoot up to 18.0 and stay there until I drive it for about 5-10 minutes then comes down to the 15's and finally settling between 13.9-14.5. I'm idling at 900 rpms at 55 map and if you notice in my tune the ve value for that cell is around 29. To me that seems low and lean which makes me think the lean startups is associated with the that ve value but when it finally warms up it's rich. I could be wrong and maybe there is something I missed so hopefully someone could lend a hand and take a look at my tune to see if you see anything out of the ordinary. I would really appreciate it, this is driving me nuts. Also do you think if I enable the maf and scale that correctly that it will help the lean issue or do you think I need to tackle this problem first then continue with the maf and enabling closed loop? Any advice would be great, thanks, Mike

[WS6FirebirdTA00]

You need to post a log, please read the stickies.

[mikeyv]

Hey guys this is a log from my work to home, I did change the spark at idle to 28 and that seemed to make my map go back and forth from 55 to 50 so maybe I need to add some more timing to get it to stay at 50. Hot idle was ok but can you look at my tune and log to see why my startups are so lean. Thanks, Mike

[WS6FirebirdTA00]

IAT is heat soaked

[svede1212]

i'd bet the lean condition on start up isn't due to IATs. i get the same thing on any startup either stone cold or hot.....i know post up a log

[WS6FirebirdTA00]

SOME of the lean condition is due to a heat soaked IAT, and I will bet you on that one. Lean cold startup has to do with OLFA.

[svede1212]

SOME of the lean condition is due to a heat soaked IAT, and I will bet you on that one. Lean cold startup has to do with OLFA.

isn't that just the commanded AFR? what controls the actual AFR vs commanded AFR on start-up in open loop. take a look at my start-up log. the commanded is lower and the actual is high. as it warms up the two converge.

[WS6FirebirdTA00]

its due to the VE or MAF calibration and the compensation your motor makes (which seem to be fairly inaccurate) for colder IAT and ECT conditions. You will actually be commanding a richer AFR to reach desired AFR on cold start. It is a PITA but there is not a whole lot that can be done about it at this time.

[jimmyblue]

I am suspicious of the wideband in the first log, it seems too steady
at 12.7 while the commanded AFR is creeping and the IAT/ECT are
solid (so should be no drift in computed airflow or fuel adders. Then
the WBO2 takes a big jump to 16:1 with no change in commanded
AFR. So either there is a big jump in something like fuel pressure
(down), or the air pump kicked on (?) or the WBO2 just changed its
tune suddenly. How confident are you in the grounding scheme for
your LC-1? There are known problems, there. Do you at least see
rough agreement between the gauge and the logged values? I'd
verify the instrument before chasing any ghosts.

[TiredGXP]

I am suspicious of the wideband in the first log, it seems too steady
at 12.7 while the commanded AFR is creeping and the IAT/ECT are
solid

Interesting comment. IIRC, 12.7 is the open circuit reading. I get 12.7's when I forget to plug in the WB connector to the MPVI.

[WS6FirebirdTA00]

Those can be set differently as well. I have mine set to 14.7 so I can make sure everything still matches up correctly. Good point though, most likely the sensor still warming up in the log (which makes it hard to get data on cold start that is correct).

[svede1212]

i'm confident in the wideband. i have a solid ground for both the heater (engine block) and the signal (OBDII ground). the logged AFR matches the digital AFR in logworks as i calibrated the LC-1 with a custom PID (i did the "every output=14.7" to get the offset). the other thing is it doesn't matter if i start up stone cold or turn it off and right back on again it does the same thing. i run SD so i think the MAF on my workbench is calibrated properly . it's not a problem as i don't thrash on it when i start it up. the sensor "warming up" makes some sense but on a short on/off/on start it has to be pretty warmed up. just curious.

[mikeyv]

Hey guys, I don't think its the fuel pressure or the air pump, I deleted the air codes and even removed the pump but now you have me thinking about the wb. It's been a while since I hooked up the wb, I believe I have all of the grounds at one spot on the block or head. I didn't even consider it being a wb problem but I did get into an accident a couple of months ago and I don't remember if it was doing this problem before the accident or not. Maybe the collision affected it or maybe even the car being in the paint booth drying in 150 degree heat contributed to the problem. I don't know, but i'll check the grounds. Do you think i need to recalibrate it? The gauge does seem to be a little off from what my laptop says like maybe .5 or so. Did you see anything wrong in the tune that I posted a couple of days ago? That jump from 12.7 to 16.1 that you were talking about, I started to log data before I started the car then once it started it shows 12-13 then just jumps to 16-17 as you can see. It just seems that something turns on at that point to lean it out but I have no clue as to what it could be. If you get a chance please look over my tune cause I think I've tried every table that would relate to the problem, maybe I missed something. Like I said before, I'll check the wb out too. Thanks for all of your help, hopefully I can rectify this problem before I go insane, Mike

[svede1212]

you shouldn't ground the heater and signal ground to the exact same point. run them to two different points and check for ground offsets

[WS6FirebirdTA00]

svede, I think the question was is the WB heating up in the beginning as the log was already running?

[02LS1Hawk]

Can you not turn the car to the ON position for about 30 seconds for the WB to warm up, or does the LC-1 need more time to warm up?

Edit: Sorry, just noticed the short on-off-on mentioned doing the same thing.