Cold Start Enrichment in pre-2003 COS

[Haans249]

Not sure why it would add fuel.
The value is a direct multiplication of the VE table numbers.
Lets assume your VE number is 1.000.
If your IAT table value was 1.010 then 1.000 x 1.010 = 1.010
If your IAT table value was 0.950 then 1.000 x 0.950 = 0.950
So given that the VE numbers end up lower I'm not sure how it could cause a rich condition.

Cheers,
Ross

Well it does haha. My IAT temp table starts with values below 1.00 and then moves to number above 1.00 in hotter IAT's. If its supposed to work the way you say, I should be starting with higher numbers to lower, but its just not the case. TAQuickness has found the same thing, and he was using the same OS I am.

Here is an example of my table:

LABELS IAT VE Multiplier (Factor)
IAT °F {link: SAE.IAT} Value
-40 0.991943
-22 0.994724
-4 0.995921
14 0.997118
32 0.998115
50 0.999113
68 1.000000
86 1.001307
104 1.002105
122 1.002903
140 1.003418
158 1.004150
176 1.004883
194 1.006348
212 1.007080
230 1.000000
248 1.000000
266 1.000000
284 1.000000

If I have a number above 1.00 in colder IAT's, it would lean out really bad. A number below 1.00 richens it up.

Best,
Adrian

[Alex99]

If you were to set A0008 to the max value allowed you should see 'some' change to the commanded AFR/EQ.

Hey guys,

after Brandon contacted me again on this issue, I have finally been able to do the above test.
A0008 seems to have a significant effect on the AFR after setting the values to 2.0 (max). Good news, I guess.
I guess I never tried to put in very high numbers because it didn't make sense.
The new question now is, why are the commanded values not matching with the actual WBO2 values.

I guess I can now start to modify A0008 to my needs, but it'll be mostly trial & error since the scaling is off.
When I did the test with max values, I got an AFR of 10.5 vs 14.6 commanded. It should have been closer to 7.5 (although it might not have run that rich).
After playing around with the table a bit I see a discrepancy of about 1 - 2 AFR points between commanded and actual, actual always being leaner than commanded.
Any thoughts on this new issue?

Brandon, thanks for following up,

Regards,
Alex

[joecar]

Make an A0008 ben map, filter out higher temps and throttle, and apply it to A0008 (very much like when doing AutoVE).

[Haans249]

Make an A0008 ben map, filter out higher temps and throttle, and apply it to A0008 (very much like when doing AutoVE).

I don't see how that would work, as that table adjusts the commanded fuel. On cold start up, you have to command a rich AFR to bring your AFR's down to 14.6. For instance, i have to command around 11.1-12.5 during my cold starts to get my afr's in line. If I were to use a ben map for the A0008, wouldn't it just continue to add more and more fuel? (commands 11.1 sees 14.1 - ben adds more, now command 9.0 sees 12.0 - ben adds more fuel etc...). I think you just have to play around with the table until your cold start idle gets in line, my table is as follows:

LABELS Open Loop ECT Commanded Fuel Multiplier (Factor)
ECT °F {link: SAE.ECT} Value
-40 1.020020
-22 1.020020
-4 1.020020
14 1.019531
32 1.014649
50 1.013184
68 1.010742
86 1.006348
104 1.000000
122 1.000000
140 1.000000
158 1.000000
176 1.000000
194 1.000000
212 1.000000
230 1.032227
248 1.084961
266 1.100586
284 1.100098

Not sure of the formula it uses to adjust the commanded fuel, but with the following table at start up of say 50F, it will be commanding 10.8 and sees 14.2-14.8, and as the motor warms up the commanding goes to normal and afr's stay relatively steady. Of course I'm sure that my VE vs IAT multiplier is also affecting the AFR's I'm seeing, but there is going to be a need for a combination of the two that will bring your AFR's in line.

[joecar]

Oh... make the ben map inverted... i.e. 1/ben.

[Haans249]

Oh... make the ben map inverted... i.e. 1/ben.

hmmm, have you tried this? I still don't think it'll work because you have to play with the numbers to get your AFR in target, there is no "correction factor" you can do to bring it in as the target AFR is not what is actually being commanded.

[joecar]

I played with it but I didn't succeed... my AFR diverges at cold startup, and slowly converges as warmup progresses.

[Haans249]

I played with it but I didn't succeed... my AFR diverges at cold startup, and slowly converges as warmup progresses.

Exactly as mine does as well as everyone else using COS in OL. Its interesting how the above A0008 table adjusts the commanded AFR. A 1.015 will command ~10.3, while 1 makes no adjustments. I can only imagine what 2.0 would command, and I'm not going to try hahaha.

[hquick]

I've had a little bit of luck playing with B3632 to try and combat the lean cold starts.