lakeffect2

I'll ask the more generic question first..

Assuming all is well, and starters batteries, injectors, fuel pressures, ingition modules and pickup coils are NOT an issue, GENRALLY how should programming for hot restart differ from cold start in terms of fuel and timing requirements.


second question on lean pops, what I'm trying to uncover.

If I stomp on the throttle for PE at WOT , I get what "seems to be" lean pop quickly, sometimes well before 3000rpm, like 2600. If I slowly increase the rpm I can get up to around 4000 before it breaks up.My fuel chart at the 3600rpm mark is at 95% and maxed at 4000.

On a data log, I'm watching the BLM's lean out as I slowly bring up the throttle past 2600rpm (trying to engage AE, but trying NOT to engage PE at WOT)

The issue I 'm concerned with is whether the stock GM Z28/firebird fuel pump can and maintain enough pressure for 32lh/hr injectors on a 400block with high flow manifold, ported siamesed runners/plenum, 58mm body and a 230/236 cam. Fuel pressure with no load, key on, engine off, is at 46lbs. I have not yet seen what the pressure does under high rpm/kpa load.


Your thoughts on either question are most welcome.

lakeffect2

Any ideas on wither question?

Hot start programming?
Why I might be maxed out of fuel and how to correct it?

dan0617

I'd say yes, there is a very good chance that your fuel pump isn't keeping up. Drop in a 255 LPH Walbro. I know in my '165 ecm there is a table in which I can adjust how soon PE mode comes in by TPS and load.

For hot restart, I have my hot restart timing retard setting at like 14 degrees. It quickly decays that retard, so immediately after the restart the timing is back to the main timing table. For cold starts, I have it adding in a degree or 2 every step down on the timing correction vs coolant temp table. I think I add in like 7 degrees when the coolant temp is below freezing temps. I also set that table so it never quits using it no matter what the temp is, and I set it to pull 1.5 degrees of timing when over 200 degrees. I was getting some slight pinging after my temps approached 200 degrees, but none when it was running 160 to 180 degrees coolant temp.

For cold start fueling, my settings are stock at startup, but I adjusted the OL AFR %Change vs coolant temp table so that it gets more fuel while warming up. Hot start fueling is also stock, so once it fires it quickly jumps to normal fueling.

I am running the same cam as you, but with a HSR intake and AFR195 heads on a 383.

lakeffect2

In TunerproRT, under "CONSTANTS" I see:

Spark Advance, Hot Restart SA Retard but it is defined in seconds (set at 25) not degrees> i doubt this is the definition field I'm after.

Another is:Spark ADV, Hot restart SA Retard, (set at 0.35 degrees) If this is the field, it's at less than 1 degree while your indication is around 14. Is this is the correct field that needs to be bumped?
I also see Spark Ret, Hot Disable Temp (set at 44.8c)

I was anticipating I'd find something in a table "SA vs Temp" of some sort.

Maybe: SPARK ADV Decay Delay Vs Startup Cooant (calc?)
That's in table form but seems NOTto be for spark, as the vertical units are labeled "injection"

Am I getting Hot? (pardon the pun)

dan0617

I wouldn't mess with any of the decay delays unless you are having a problem. The Spark ADV hot restart SA retard, is how much it will retard the timing for the start when you start the car hot. I bumped mine up to 14 for 14 degrees of retard because my compression is so high I was getting detonation just as the car fired when starting hot. Would sound like someone smacked the front of the engine block with a 2lb hammer once or twice on startup.

I can look when I get home tonight at what it is called, but in the bottom column (tables), there is a table that I use that is called something like "spark advance compensation vs coolant temp vs lv8". It lets you choose the advance correction desired by load and coolant temperature, and you can put negative values in the table. I have mine pulling timing when at hot operating temperatures, 0's at normal operating temperatures, and adding timing when coolant is cold (during warm-up). Then, in the top column (constants I think), there is a setting that lets you set when you want the computer to quit looking at the correction table. I set mine as high as it would go because I always want it to correct spark according to the table.

I believe the "Spark Advance, Hot Restart SA Retard" that you said is in seconds, is likely "dec" not "sec", which shows the decimal. If you change the one that is in degrees, it will also change the decimal one automatically.

dan0617

-2.11 -2.11 -2.11 -3.16 -3.87 -3.87 -4.92 -4.92 -4.92
-1.05 -1.05 -1.05 -2.11 -2.11 -2.11 -2.11 -2.11 -2.11
0.00 0.00 -1.05 -1.05 -1.05 -1.05 -1.05 -1.05 -1.05
0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
0.70 0.70 0.70 0.70 0.70 0.70 0.70 0.70 0.70
0.70 0.70 0.70 1.05 1.05 1.05 1.05 1.05 1.05
1.05 1.05 1.05 1.41 1.41 1.41 1.05 1.05 1.05
1.41 1.41 1.41 2.11 2.11 2.11 1.05 1.05 1.05
2.11 2.11 2.11 2.46 2.46 2.46 2.11 2.11 2.11
2.46 2.46 2.46 3.16 3.16 3.16 2.11 2.11 2.11
3.16 3.16 3.16 3.52 3.52 3.52 2.46 2.46 2.46
3.87 3.87 3.87 3.87 3.87 3.87 3.16 3.16 3.16

Above is my "spark correction coolant temp vs lv8" table, in the tables/functions section. works pretty well for me. Not as much timing added as I thought when I posted my first post, but now I'm at home and looking at it.

My "Coolant temp spark correction disable temp" in the Constants/Scalars section is set to 304 degrees F so it never quits using the table listed above.

41.84 41.13 37.97 36.91 33.05 31.64 29.88 28.48 28.48 28.48 28.48 28.48
41.84 41.13 37.97 35.16 32.70 31.99 28.83 27.07 26.02 25.66 25.66 25.66
41.84 41.13 37.97 35.16 32.70 31.99 28.83 27.07 23.91 23.55 23.55 23.55
41.84 41.13 37.97 34.45 32.70 31.99 28.83 27.07 23.91 22.85 22.85 22.85
41.84 41.13 37.97 34.45 32.70 31.99 28.83 27.07 23.91 22.85 22.50 22.50
41.84 41.13 39.02 34.45 31.99 30.94 28.83 26.02 23.91 22.50 22.15 22.15
41.84 41.84 40.08 35.16 31.99 30.94 28.83 26.02 23.91 22.50 22.15 21.09
41.84 41.84 40.08 35.16 31.99 30.94 28.83 26.02 23.55 22.50 21.45 20.04
41.84 41.84 40.08 35.86 33.05 29.88 28.83 26.02 22.85 21.09 20.39 19.69
41.84 41.84 40.08 36.91 34.10 29.53 26.02 23.55 22.15 21.09 19.69 18.98
41.48 40.08 39.02 35.86 33.05 28.83 24.96 22.85 22.15 20.39 18.63 17.58
40.43 35.86 35.16 33.05 29.88 26.37 23.91 21.45 19.34 18.63 16.88 15.47
33.05 31.99 30.94 29.88 28.13 24.96 21.45 18.63 16.88 15.12 14.06 13.01
26.02 26.02 26.02 26.02 25.66 23.55 21.09 16.88 14.06 11.95 11.95 11.95
24.96 24.96 24.96 24.96 24.96 22.85 21.09 16.88 14.06 11.95 11.95 11.95
23.91 23.91 23.91 23.91 22.85 22.15 20.04 16.88 11.95 10.90 10.90 10.90
23.91 23.91 23.91 23.91 18.98 16.88 15.12 15.12 11.95 10.90 10.90 10.90

That is my main timing table. Keep in mind my compression is really high so I run less timing and get good power that way. PE SA is 0'd out.

I keep my WOT air fuel ratios between 12.2 and 12.7 when not spraying. Part throttle I try to run 13.2 to 14.0 but it floats a little outside of that sometimes. Runs great so I don't worry that much about it.

I have an expanded 6E XDF file for Tunerpro, it gives you quite a few more things to change than the normal 6E XDF file for Tunerpro. If you want it PM me your email address and I'll send it to you, and I'll send you my current .bin file. My .bin file is kind of wierd compared to most, and is full open loop, but it works great for me. Forum member Orr89rocZ sent me his .bin file when I started tuning and it was a HUGE help to be able to compare what I was doing/changing to his .bin. BTW: Thanks again Orr!

Orr89RocZ

iTrader: (20)

Look at your crank fuel pulsewidth vs coolant temp table. this is for startups. On a hot startup you need LESS fuel so the table should taper to more fuel the colder the engine temp.

If you have trouble getting it to fire on hot startups, it may be getting too much fuel. Quick check is if you can hot start the car with the throttle down to open up the throttle blades. If it starts then thats a sign more air was needed thus being too rich. Take some pulsewidth out of that table at the coolant temp you are at.


The less timing on start up helps as well as explained above.

Good to see that car is running strong and you got it all figured out. If i would have known you were over 12 to 1 compression (maybe I did and forgot) I would have tapered those timing tables down alot more.

MikeT 88IROC350

Yes, exactly. Too much fuel at hot temps will cause hard starting. I had this exact problem. Just lower your crank fuel PW at startup, vs temp. I lowered mine quite a bit when engine warm. Also depends on whether you got that 9th injector working or not. Might look at the crank fuel PW vs ref pulse tables as well.

Good info above on the coolant spark correct vs temp. and LV8. gonna have to take a look at that myself.

Gotta love this stuff1

Orr89RocZ

iTrader: (20)

Good table, i never used it before on my setups but am considering trying to use it on my turbo build, especially when the motor starts getting hot. My previous motors never ran hot so I never had use for that table but on cold starts it probably would have been nice to keep idle advance up alittle more then taper down as it heated up.

MikeT 88IROC350

[QUOTE=

My "Coolant temp spark correction disable temp" in the Constants/Scalars section is set to 304 degrees F so it never quits using the table listed above.

[/QUOTE]

What about the constant "Coolant Temp spark correction Bias"? Mine is set to 20deg. Do you have to consider that in? Or is that just what your base timing is set to until you warm up and NOT use the table?
Also, is the 3-D table a function of load (LV8) or MAF (gm/sec)? I see a conflict between TunerCat and TP.

lakeffect2

Maybe I mislead you, or now have abetter handle on what I'm seeing.

I am getting lean outs on hot restart. Afr goes to 20 and stays there during open loop cycle to the point tady it was stalling out. I can tell when closed loop hits as the AFRr drop to the mid teens immediately.

So I'm trying to correct for a few things here, and maybe lack of proper spark retart for rhot restart is apart of the open loop issue.

Further comment?