ls1b fuel limit?

[dian]

what is the pcs fuel limit on my 99 c5? po1, right? 02020003/cos3.

2.32g/cyl, 2.23? which is a typo? something else?

thanks.

[nonnieselman]

Unsure how you answer your question. but you can scale the injectors to get more out of the Fuel tables.

[dian]

thank you. sure i can scale, the question is if i need to.

there are various numbers floating around, probably depending on the particular set up. i would like to know what it is in my situation. im mafless, if that makes a difference. (i never had problems with the 512g limit, btw.)

[nonnieselman]

I dont scale unless im past that 1.2g/cyl limit and id like to use the spark table more than the Boost timing retard table.

[dian]

thank you. the more i try to research this the more confusing it gets.

a lot of old discussions without a clear result. i would have thought it must be clear by now.

1. the "hard coded" limit of 512g/min (corresponding to e.g 1.28g/cyl @6000rpm): does this go away with the cos3?

2. where do the other numbers i see come from (1.36, 2.23, 2.32, 2.4, 2.5 g/cyl)? are these conversions at lower rpms? unlikely. other ecus?

3. why do you scale at 1.2? to get more resolution of the spark table, maybe?

iv been running the engine in sd at slightly over 2 g/cyl for nearly 10 years now, without the slightest problems and without any scaling. now im reaching 2.3-2.4g/cyl and i got rep twice (no codes except p0101/3). im on the edge of traction, so trying to figure out if its tc-related or some "hard coded" limit haunting me. of course i would like to avoid finding out experimentally.

[nonnieselman]

Yea it gets quite confusing.

1) Dunno
2) DUnno haha
3) yes so i can keep on the spark table but for an Automatic you also have to rescale the transmission pressures to keep everything happy.

On the last 2005 turbo truck i had all kinda problems trying to keep it from pulling timing in 4th gear towing up hills.

Ended up scaling injectors back and kept doing that till i got it down to 1.00 G/CYL for 10psi at 2300 rpms and then had to deal with trans pressures and redoing the spark table.

Ive since just use Holley ECUs on turbo/nitrous builds. Makes it so much easier and faster to fine tune.

[dian]

have you looked at est_xmsn concerning those timing problems? im finding its pulling timing in various situations or not. (sometimes its "active" and run-spark is unaffected.)

i wonder about (3) though. why not use a0010?

edit: just saw this. fresh set of nubers.

"GM upped the upper limit several times through the years on gen 3's I think from .78 to 1.2 or 1.6 but its always been hardcoded." (Bill@HPTuners)

and more: "hard coded limit is 254 lb/hr....fits the FIC 1000 with no scaling" (p59).

[nonnieselman]

have you looked at est_xmsn concerning those timing problems? im finding its pulling timing in various situations or not. (sometimes its "active" and run-spark is unaffected.)

i wonder about (3) though. why not use a0010?

edit: just saw this. fresh set of nubers.

"GM upped the upper limit several times through the years on gen 3's I think from .78 to 1.2 or 1.6 but its always been hardcoded." (Bill@HPTuners)

and more: "hard coded limit is 254 lb/hr....fits the FIC 1000 with no scaling" (p59).

Ill have to check that out. I datalogged all of the PIDs i could find for spark and TM to no avail.
Once i scaled injectors back all those problems went away.

I use A0010 sometimes but dont always need to pull that exact amount of timing. So i like using the whole spark table and use A0010 for a overboost safety.

[dian]

are we actually the only two guys using the forum, besides joe? what happened? is efilive dying out? i recently tried to locate a dealer to get a connector and it seem there are none in europe.

[nonnieselman]

Im not sure. This forum has surely died out over the past few years.
Its so sad now days. I tune a few cars/trucks a week and nobody has ever heard of EFI Live. They assume HP Tuners is the only thing out there.
I run into issues with guys bringing me stuff thats been tuned with HPT with one of their operating systems and i have to read it off with my HPT box and save it. then converter it over to a efi live COS to tune it.
If i didnt already have a few stream licenses id prolly jumped ship but i despise the HPT layout. Guess cause ive used this EFI Live for 20 years.
Ive slowly converted most the turbo or nitrous guys over to holley ECUs since its much easier to setup and tune some the setups with boost control, progressive nitrous and traction control.

[dian]

have you ever tuned an ls7 for boost?

[nonnieselman]

LS7 comes in them expensive cars hahaa
I mainly fool with truck stuff with cheap 5.3s or 6.0s. And build 408 or 427s for race cars.
But ive done a few dozen Dart Block 427s in these light weight race cars but we running M1 in all of them.

[dian]

i should have asked about the e38 instead of ls7, i guess. comming from the po1, i wonder how steep of a learning curve it is. the project has been on a backburner for a while, because i cannot find the time.

[nonnieselman]

I struggle with all the Gen 4 stuff sometimes. The Gen 5 i only tune for DOD Deletes and stock everything else. They are too complex for me.
E38 can be quite a chore to deal with if your only use to the LS1B pcms.

I have some write ups on how to fool with them but the last few that i tried to tune with decent size cams always had quirks i never could figure out. I have a buddy that owns a performance shop that does tuning on all the newer Gen 4 and gen 5 stuff so i send them all his way. he sends me his customers that have Holley ECU's and older LS1B pcms.
Thats how i get around that curve ball.

[dian]

and another number yet:

"not sure how it does the caculations....i was seeing 2.09 g/per cyl @ 13.X psi when it set code" (p1514)