95 LT-1 Idle Cell Comparison - Humidity?

[kur4o]

I justflash a stock bin with the beta and evrything looks fine. There is no brick situation and the engine starts. I didn`t have the time to test functionality.
So you can safely flash with the beta. There will be no suprises.

I also noticed how to add info buttons to explain how to use the extra controls. Next on the list.

Now with stock bin I found that the engine starts harder, at the 3rd 4th attempt, but the cold idle was incredibly smooth and tamed. I haven`t heard the engine running that healthy from a long time.
So what was the difference. 4 less degrees advance, stock underspeed and maf tables and much more fuel being dumped. I guess I need to be back on the tunnig board.

Some log for comparison.

[spfautsch]

I'll probably pass on testing until I'm done getting my tune at a respectable baseline - it's coming along really well so I'd rather not get distracted with other stuff right at the moment. I've been switching between your fork and an old version of the original that I've customized.

Now with stock bin I found that the engine starts harder, at the 3rd 4th attempt,

Are you stock cubes but bigger injectors?

I've been messing with that 12680 multiplier with the stock base pulsewidth table. For the sake of discussion let's call it a two byte table where both bytes must match (similiar to the target AFR tables). I followed your advice at first and used 0x44 (in both bytes). It seemed to be a little lean - hot restarts popped right off if I bumped the key and then hit it again after 5 seconds. So I went to 0x55. It hits every time but seems to be pretty rich there. I tried 0x4F and it still seems a bit rich so I'm working my way down from there. Whatever the case it's hitting on the third or fourth low res pulse every time now regardless of ECT.

[kur4o]

an old version of the original that I've customized

You can share the new goodies and I can try to include them in the new release. The key shortcuts are very usefull, I still haven`t had the chance to expand them to more controls.


The 2bytes table whenever is changed, the prime pulse tables must be adjusted to compensate for the new offset factor.

With stock settings at $6666 the stock table will look like this

215.63 215.63
209.38 209.38
120.31 120.31
59.38 59.38
39.06 39.06
17.19 7.81
12.50 6.25
7.81 4.69
7.81 4.69
7.81 3.13
6.25 3.13
6.25 4.69
6.25 4.69
6.25 6.25
6.25 6.25

When the 2 byte table is changed to $4444
The table will look like this with new conversion factor (1.007028* X) + 0.000000

138.97 138.97
134.94 134.94
77.54 77.54
38.27 38.27
25.18 25.18
11.08 5.04
8.06 4.03
5.04 3.02
5.04 3.02
5.04 2.01
4.03 2.01
4.03 3.02
4.03 3.02
4.03 4.03
4.03 4.03

So whenever the 2 byte table is changed you need to readjust the prime pulse tables.
With $4444 scalar the resolution goes to 1ms intervals vs 1.5 ms at stock $6666 settings.

hot restarts popped right off if I bumped the key and then hit it again after 5 seconds

I have done this on a cold start with the same result. Adding fuel didn`t help at all, so my assumptions it is actually rich.
Hot restarts are tricky to tune and test due to some variables that can change on the fly. The main issue will be how much fuel left on the walls unburned with the engine switching off.

The prefect start will be at sub 0.3seconds only on the prime pulse fueling. Than the crank ve tables hit with 2 different afr tables based on low res pulses.

I found some 96 lt4 bin and explore the differences. The idle advance is set at 19* at cold coolant and gradually decrease to 14* while warming. On the lt1 f-body is reversed. Really interesting.



I have changed the injectors onlyThe ls` ones flows 24lb at 3bar, so no change with fuel flow. With the old some crap accell 24lb/hr I didn`t have any hard start issues even with completely stock bins.
So it could be the injectors needs some tweeking or the ls1 injectors patch I run needs some attention at starting routine.



I also tried the vette CL settings and the logs I made are on par with yours. Slight blm split and less crosscounts. The idle runs perfect in closed loop.
I have some theory how to tune the CL settings for more crosscounts, but need to test some of them to confirm how they work.

The off idle trims made huge difference at cruising around 1500rpm. I wonder how far we can go using them safely before the air stream equalize in the cylinders.

Stock settings are at 0-14% tps, <3000 rpm and no catprotect and PE.

On the lt4 bin the tps is at 24%.

I want to increase the tps as much as possible and add new conditions such as airflow or map thresholds.

[spfautsch]

You can share the new goodies and I can try to include them in the new release. The key shortcuts are very usefull, I still haven`t had the chance to expand them to more controls.

There really isn't anything new or terribly worthy of sharing. I did recently fix a problem where the IAC override would set it to 4 (steps) and not change if switched to step mode. But that might have been a bug I created. Aside from the key accelerator stuff it was mainly making fields like knock count and stuff big enough this old blind guy could see them on the 11" screen.

With stock settings at $6666 the stock table will look like this

...

When the 2 byte table is changed to $4444
The table will look like this with new conversion factor (1.007028* X) + 0.000000

I think I'm pretty clear on that. I suppose what I'm confused on is if I were to set 12680 to 0x4c4c why wouldn't the prime pulse table look like this with 1.16ms intervals:

160.034    160.034
155.396    155.396
89.294    89.294
44.067    44.067
35.950    35.950
17.395    17.395
12.756    12.756
5.798    5.798
5.798    3.479
5.798    2.319
4.639    2.319
4.639    3.479
4.639    3.479
4.639    4.639
4.639    4.639

???

You won't hurt my feelings to tell me why I'm being a bonehead as long as I can learn something from it.

Hot restarts are tricky to tune and test due to some variables that can change on the fly. The main issue will be how much fuel left on the walls unburned with the engine switching off.

The prefect start will be at sub 0.3seconds only on the prime pulse fueling. Than the crank ve tables hit with 2 different afr tables based on low res pulses.

You'll get no argument from me that restarts in general are tricky with different injectors, displacement, etc. I tested the above multiplier tonight (0x4c4c) and had a very obvious flood at 73c restart (fired then died, required pedal to clear on 2nd attempt). This is why I was curious if we have any idea if injector offsets are added to the prime pulses. Then we get to the subject of having good injector data. My ecm is seeing 10v average during cranking. that's about 1ms of offset for the stock injectors. If my offsets are wrong, how far off are they?

So it could be the injectors needs some tweeking or the ls1 injectors patch I run needs some attention at starting routine.

You should put my experimental ignition system on it so you have another unknown! (joking)

I also tried the vette CL settings and the logs I made are on par with yours. Slight blm split and less crosscounts. The idle runs perfect in closed loop.

Mind sharing a screenshot of the BLM analysis?

I'm pretty happy with my VE table after tonight's log so I think I'm going to turn the MAF back on and fine tune a bit. Probably mostly on the damned prime pulse / restart issue. Beyond that I'd be happy to test any closed loop tweaks you would care to share.

I want to ... and add new conditions such as airflow or map thresholds.

If you can do that I can surely conquer startup fueling.

[kur4o]

why wouldn't the prime pulse table look like this with 1.16ms intervals:

It is exctly like that. I have nothing to add. What I mean is that you can fine tune the tables from there.

So for now I want to end the disscusion on the pw scalar since it is all clear.

The 2 bytes table should be called. Multiplier to startup prime PW table.

The formula for the multiplier will be d={x*0.0152587891}/256

The multiplier decimal result must be entered in the crank prime tables conversion field with the following formula {x*d}.

Now you can start fine tunning with the new multiplier.


The InJ vol offset are for sure used during cranking. I improved that part of my patch with major improvement on the first start attempt.

I am starting to suspect that my ls1 inj flows more than specified at 100kp range. That explains the hard startup[rich condition] with stock settings.

I am getting rich right side at cell 6 only, 3-4 points split. I check logs with older settings and the split is also there at #6 cell. At other cells the split is negligible.
I also changed the off idle trims but it seems they don`t affect the split.

I experience zero split at idle so far. I tested it for a short period so it could be not very reliable.

I thought for a way how to find the break point for off idle trims condition.

Setting the trims on one of the side richer and look for the conditions where the blm splits equalize.
Than set the tps map thresholds.

I already made the map threshold patch but it interferes and interacts with the v5 patch so it is a little tricky to install. If you want to give it a try I will set you a bin. If it turns out bad I can change it to an air flow condition.


I suspect the $26fb table to be responsible for the crosscounts. It is also the cure for idle CL along with the swing voltage.
AT $26fb slightly increasing the values at cells 2-5[don`t touch the first cell- it is for idle]

y-stock ;f-stock ; my old settings
0.40 0.80 1.20
0.18 0.18 0.35
0.13 0.13 0.25
0.11 0.11 0.23
0.10 0.10 0.20

As you can see I thought more is better but not for the first cell. For the first cell less is better, almost twice less at stock y-body vs f-body.
At cell 2-5 increasing the value can lead to higher crosscounts. Field discovered by mistake. Not sure how good is this for engine running healthy but you can give it a try.

$270c is also different but not in the idle region. It also can attribute to the crosscounts but needs testing.
The main difference is at cells 2-5
vette; f-body
0.3 0.5

and the swing voltage
380 for vette
vs
460 for f-body

[kur4o]

Your problems with hot restart might be due to crank spark advance. I ripped the settings from different calibrations.

Interesting I am running 2 degrees at 80*C and 7* at 20*C stock. The closest to cammed car is lt4 setting at 5* and 11*, all other calibrations have 8-10 * and 13*.

I suspect this might be culprit with my issues of first cold start.

So it could be hot restarts needs less advance and first cold start needs more advance.

[spfautsch]

Interesting there's that many differences between the stock bins. On a whim I just tried the lt4 cranking spark table. Before this change pretty much all starts with anything under 0x50 in 2680 was somewhat slow and slobbery. With the lt4 startup spark it start and ran cleanly. Still hit on the 3rd or 4th low res pulse.

Unfortunately the weather has changed dramatically here so I almost need to wrap my engine and radiator in a blanket to get a hot restart at 80 ECT. Ambient is > 10c cooler than last weekend so air density way different also.