Cold AFR doesn't follow commanded AFR

[LS1_Dragster]

I was wondering what causes the WBO2 AFR to not match the commanded AFR when you start the vehicle cold? I have 3 cars I've done now and all 3 are the same.

I attached a log of the firebird, you can see that they are not even close. Any ideas where I could look?

Lee

[LS1_Dragster]

I guess I should of attached the tune also.....

[mr.prick]

In SD this happens for me too,
but once the MAF is enabled and tuned it is cured.

[LS1_Dragster]

No way I'm putting a MAF on this car!!!

http://www.horsepowerracing.com/firebird/firebird_eng1_s.jpg

[mr.prick]

:hihi:
Nice ride,
look in the Crank/Start folder for other "options".
How about hanging the MAF from the rear view mirror? :laugh:

[LS1_Dragster]

It looks like there's a real need for a true speed density OS, one that is scaled down without all the useless tables, kinda like the Holley commander software!!

[Aloicious]

:hihi:
Nice ride,
look in the Crank/Start folder for other "options".
How about hanging the MAF from the rear view mirror? :laugh:

yeah, that is nice. what color blue is that? i'm diggin' it.

I've had the same issues with cold start AFRs too with both SD and MAF. if I ever figure out what it is I'll let you know.

OT, yay, bill cosby is back, no more vomitting dog.

[mr.prick]

That is a nice color blue, my old man had a '67 Firebird that was a similar color.

I missed the COZ too. :hihi:

[Aloicious]

That is a nice color blue, my old man had a '67 Firebird that was a similar color.

I missed the COZ too. :hihi:

yeah I was looking at simmilar stuff to paint my '68 firebird back when I had it.

that dog picture was disturbing. :shock:

[SOMhaveit]

Desired Air Flow numbers appear to be on the low side and idle spark is 36 degrees.

You have all of the spark tables with high spark values around idle and then have lowered optimal spark values compared to oem values around idle.

Aside from that, your actual AFR compared to commanded ain't all that bad.

[LS1_Dragster]

Thanks for the replies.

The color is House of Kolor Kandy Majestic Blue over platinum silver base. I will paint stripes on it this winter, I just havent had the time to complete it. Here are a few pictures from the autorama:

http://www.horsepowerracing.com/firebird/firebird_show_s.jpg

http://www.horsepowerracing.com/firebird/firebird_show2_s.jpg

[LS1_Dragster]

Desired Air Flow numbers appear to be on the low side and idle spark is 36 degrees.

You have all of the spark tables with high spark values around idle and then have lowered optimal spark values compared to oem values around idle.

Aside from that, your actual AFR compared to commanded ain't all that bad.

Air flow may be low because I have an edelbrock vic jr and Holley throttle body. Since these are not stock I had to work the program around them.

I have found with the other cars I've done with larger cams it loves a lot of timing around idle, it tames them a lot and "takes the cam out" so to speak. If I understand the CO3 correctly when I set A0000 To enable and A0001 to 100% it will only use the high octane timing map.

Commanded AFR is getting better as far as driving goes, I've only put on a few miles since the rebuild. I was just concerned as to why cold AFR is not achievable.

Lee

[vxchev8]

Look at table A0008 - When using {B3647} "Commanded Fuel vs RPM (Normal)" to define the commanded fuel, this table is used as multiplier based on engine coolant temperature.A number of 1.00 will add no more fuel based on the engine coolant temp, any number higher than that will add fuel.

Also have a dip in IFR b4001.

Are you running ls1 - 346ci ? your vin number indicates a gm light chevy truck and your {B0104} Cylinder Volume is 957.

[LS1_Dragster]

A0008 is what I use for the cold start fuel enhancement, the larger the numbers the lower the AFR goes but it doesnt show the same drop in actual AFR.

I do have a dip, never noticed. I just cut and pasted from the IFR spreadsheet program thats floating around on this site.

No, the engine is a 98 454 L-29 and 4L80E trans, I just changed everything to make it work. I wish I could edit those fields so I could put in what the engine/year etc really is. In fact if I change the VIN to the firebird's I loose the PID's.

[vxchev8]

remember the afr command table in COS3 is no longer temp v map but rpm v map. As such you need to adjust a0008 so you are not running lean or too rich at cold start up. Also idle speed at different temps have an effect.

Beautiful looking car :grin:

[Highlander]

It looks like there's a real need for a true speed density OS, one that is scaled down without all the useless tables, kinda like the Holley commander software!!

I don't see why? COS5 works like this.

I've had this issue with my stock z06 and my guess there is another multiplier that we do not have access too.

What i did was command a richer afr and be done with it.

[Highlander]

Air flow may be low because I have an edelbrock vic jr and Holley throttle body. Since these are not stock I had to work the program around them.

I have found with the other cars I've done with larger cams it loves a lot of timing around idle, it tames them a lot and "takes the cam out" so to speak. If I understand the CO3 correctly when I set A0000 To enable and A0001 to 100% it will only use the high octane timing map.

Commanded AFR is getting better as far as driving goes, I've only put on a few miles since the rebuild. I was just concerned as to why cold AFR is not achievable.

Lee

is your throttle body an ETC TB?

[LS1_Dragster]

The Holley just has a couple of tables and is real easy to work with, none of this table modifies this table and BTW there are 3 other tables that effect the first table....etc.!!

I'm not sure what an ETC TB is so here's a picture of what I have:

http://www.holley.com/data/products/pictures/large9900-171.jpg

[vxchev8]

Electronic Throttle Control (ETC) (http://en.wikipedia.org/wiki/Electronic_throttle_control), your tb is cable driven.

[LS1_Dragster]

I should of known, but it just didnt click!

[hquick]

No, the engine is a 98 454 L-29 and 4L80E trans, I just changed everything to make it work. I wish I could edit those fields so I could put in what the engine/year etc really is. In fact if I change the VIN to the firebird's I loose the PID's.

You can....I think.
My VIN used to show as being an Express or Savanna depending on what base tune I used....either that or 'unknown' if I used my correct Vin.
You can go into the Program files, EFILive, V7.5, Configuration and alter the 'Vin' file to read what you want in your 'VIN' tab in the tune.
I put my 'correct' numbers in and just added lines to make it read Chevy truck - Australia.

[joecar]

Very nice car, very nice colour.

[LS1_Dragster]

You can....I think.
My VIN used to show as being an Express or Savanna depending on what base tune I used....either that or 'unknown' if I used my correct Vin.
You can go into the Program files, EFILive, V7.5, Configuration and alter the 'Vin' file to read what you want in your 'VIN' tab in the tune.
I put my 'correct' numbers in and just added lines to make it read Chevy truck - Australia.

When I changed the VIN to the actual firebirds VIN then when I loaded it next it said it couldnt valid the PIDs or something like that so I put the original VIN back in. I think if you put in a valid VIN it would work. I suppose I could mess with it some more...

Thanks joecar.....

[Aloicious]

When I changed the VIN to the actual firebirds VIN then when I loaded it next it said it couldnt valid the PIDs or something like that so I put the original VIN back in. I think if you put in a valid VIN it would work. I suppose I could mess with it some more...

Thanks joecar.....

the firebird's VIN is probably a different format than the PCM is able to recognize due to its age. my 12200411 PCM recognizes my '96 truck VIN just fine. and I'm able to use all the LSx PID's without an issue.

[hquick]

What's the firebirds VIN?

[waterbug1999]

Mines the same way on on cold start but is like 18.0 then will slowly come down to match the commanded AF once the car gets to ~130F then its pretty close..... Ive tried alot of different things but no luck, so I guess ill just have to call it normal.

[mr.prick]

Drop the commanded AFR in the cold ECT areas.

[waterbug1999]

Drop the commanded AFR in the cold ECT areas.

you talking in B3605?

[LS1_Dragster]

Question, what is a good target AFR when cold?

I basically just keep richening it until it stops surging, is this an acceptable practice?

[waterbug1999]

Question, what is a good target AFR when cold?

I basically just keep richening it until it stops surging, is this an acceptable practice?

For me, I would like to get it closer to the commanded fuel (B3605).. Its in the 13 A/F range in the table, but its no where near that. So, something else is going on.

I did load what you sent over by the way, the car didnt like it too much and barely start if not die. I did however use it for comparison and have been trying different things. I think its gotten better so thanks for the help.

Ive been playing around with the B5934, B5935 and B5936.. My RPMS jump to ~1300 and down to ~400 (upon start up, and gets better after about 10 secs) and the timing jumps all over the place as well.. By reading the descreptions, it sounds like the car was adding too much timing one way, then taking out too much the other way...

I was told that timing can play a big factor in surging, 25* is ideal for idle, so I have been trying to get that nailed down and its close, better then before. Now I am trying to see what I can adjust to get the AF down to the commanded.