So I did have issues with the WB sensor but I thought I ironed them out. Car was running fine and starting fine. It was lean(16-17.0:1) on startup prior to this but now I am just confused. I logged Cracker Airflow, Follower Airflow, and Base spark in the histos to try and fix my decel and cruise issue and then input the values(which seemed low) into my tune for the follower and cracker airflow. Went to start up car and after the WB warmed up it said like 19-21.0:1. It definately idled different than before. So after about ten seconds of being confused I gave her a little gas to about 2K rpms and watched the WB go down to about 15.0:1 and then let off and watched it go back to ~19.0:1. What the heck? Do the Cracker airflow and Follower airflow affect AFR that much?

 

Are you in SD? I can't remember. I have seen it be really lean on startup without a maf for a inital period of time before it comes back in line. What is the commanded AFR for when it is like this?

 

Damn, you always ask these questions that I know I should remember but I never can. LOL. I am in SD but I dont remember what the Commanded was. Would the follower and Cracker airflow values change the startup AFR? Should I just increase the OLFA a bunch and see if it goes down? Car runs fine as soon as it gets out of this weird warm-up state.

Have you ever seen a SD car thats shows GOOD(10-12.0:1) startup AFR values?

 

The follower can I belive, but the cracker won't. The cracker isn't enabled until you reach a set MPH.

Yes, with a MAF.

What temps is this happening at? Find out the commanded before you start "fudging" numbers.

 

It happened yesterday and all were warm startups between 160-185F.

I do know before from looking at old logs(prior to yesterday) that my commanded was 11.xx-12.xx on startup and WB showed around 16.XX. Once it went CL and commanded went to 14.63 it took TWO frames to change to 14.XX range. This is what I dont understand. Startup OL values have NEVER matched up with the WB.

 

Sounds like you have the AIR pump turned on.


-Ken

 

Alright, its physically not in the car anymore. Is there a table that adds more airflow during startups that I need to ZERO out if I remove the AIR?

 

I have seen this before too, can't explain it either....

 

Its just kind of scary. Especially since the AFR goes back to normal after this phase goes away which tells me that the WB is working correctly. I just want to make sure that I am not harming the engine on every start! (more than normal at least).

 

if you're talking about that little lean blip on startup that lasts less then a second... no, you're not hurting the engine at all..


if you're refering to something that reads really lean until the car warms up or some other prolonged peroid of time, THEN id wonder whats going on..

 

Its definitely more than a second blip. I would say a good couple minutes before it goes away. I am going to go home and do a sanity check on the tune to make sure that I didnt miss or change something obvious. Then I am going to add a bunch of fuel to the OFLA and see if that wont fix it.

 

Yep, takes about 2 minutes to get down to around 14.8 AFR. Start around 19-20 and slowly works its way down. I multiplied the OLFA table by 1.25 so we will have to see what happens!

 

My EFIlive OLFA table shows lamda, so your 1.25 would actually be very lean. Make sure you're working in the right units first.

 

Ahhhh........confused. I found out that I had the AIR enable temp still at 14F. Even though I removed the hardware for the AIR it still somehow changes the AFR. I changed the AIR enable temp to 284F and wrote the tune. Started the car and the AFR started at 13.0:1 and stayed there(although it should increase slowly which is still confusing) until CL and then jumped to 14.7:1. So now that I have control of this beast, what is a target startup AFR? 12:1? 11:1? 10:1?

 

I can't think of anything but hardware that would do what your talking about in the AIR system ?
I'm confused now..

 

That entirely depends on the engine (coolant) temperature at the time of start-up. Colder needs more fuel as you should be seeing in your OLFA table.
The factory setting is generally more rich that what you really need though.
Later I'll look at a table I recently did that had a very nice cold-start curve.
I got to spend at least 3 days with that car to monitor true cold starts with the temp down in the 30's, which explains being able to get it adjusted so well. Having multiple days to tune is about the only way to get it right.

 

This is from a car that normally runs quite a bit cooler than stock due to having no thermostat. It is also tuned for OLSD (open-loop / speed-density) and I did NOT target an AFR of 14.6:1, but something closer to mid-15:1 AFR's at light loads once the engine is warmed up.
The exact numbers here aren't so important as the trend. For actual cold operation, which normally is shortly after starting (until warmed up), you want to be running richer than stoich. As the temp increases the engine will tolerate and prefer leaner AFR's.
If you plot the curve you see it gets steeper in the colder regions of the table. Since the burn-rate at these cold temperatures is so slow, you will also need to compensate for coolant-temp in the spark advance table as well. The richer mixtures in the cold engine will want more advance.

This car idled right around 12"hg so these values are from the 12"hg column of the Open Loop Fueling /Coolant Correction table.

ECT (engine coolant temperature in *F) => table value
-4 => 0.680
14 => 0.700
32 => 0.740
50 => 0.788
68 => 0.820
86 => 0.850
104 => 0.931
122 => 1.000
140 => 1.000
158 => 1.020
176 => 1.060
194 => 1.060

In this table when the coolant temp is 14*F the idle will be about 30% rich.
As it warms up to 122*F it will have worked its way to about stoich. When it gets to normal operating temperature it will be about 6% leaner than stoich.
I have it running leaner than stoich at idle and most light cruise, but the higher load columns of the table I leave at 1.000 for normal operating temperature to simplify VE and PE tuning for high loads. After all why pull 6% here just have to add it back for PE? makes little sense to me.

 

My LC1 will read in the 17's while it's warming up. Once the LED stops flashing, it goes straight to the right AFR. Is this what your seeing? Did you hook up the LCD light?

 

I have been able to lower the AFR to where I want it. Now for some reason it wont ramp up from 11.0:1 to stoich but thats alright. Atleast its not starting in the 19.0:1 range anymore

 

What did you adjust ?