Suggestions on most efficient way to tune after installing FAST LSXrt intake...

[sac811]

Basically I'm wondering where to start from when going about tuning for the FAST 102mm TB and 102mm LSXrt intake, and ditching the MAF:

1. Start over with stock Desired Airflow tables and tune using Calc.VET? Or is there a more efficient way to tune VE table without the MAF?
2. Should I stick with the stock OS, or would I be better off with a custom OS? If so which one?
3. Any other tips on things to tune for or look for when going about all this without a MAF?

I believe I am going to stay Speed Density, but go closed loop.

4. I'm assuming closed loop is the best way to go about getting the best gas mileage?
5. And also still be able to do DFCO and possibly Lean Cruise with a custom OS?
6. Any other things to mess with in stock OS or custom OS for better gas mileage in speed density/closed loop?

If it matters, this is my tune before adding the FAST intake on my 1999 GMC sierra lq9 with cam, etc:

16212

Thanks

Jeremy

[joecar]

No, start form where you are currently and do AutoVE (which is a special case of Calc.MAFT) using CALC.WO2BEN from the Calc.VET thread

( noting that CALC.WO2BEN is defined as {GM.EQIVRATIO}*{EXT.WO2LAM1} ).

If you're not boosted then stay with GM OS.

Once you get VE corrected, try doing AutoMAF (which is a special case of Calc.VET) using CALC.WO2BEN... if it works out there is no reason to not run the MAF, but will require a straight section of plumbing before/after the MAF.

Yes, you can do CLSD... CL usually gives good low/part throttle driveability.

You can do DFCO and LC with the GM OS (need a cax for LC), but I don't reallt like LC (my $0.02).

[sac811]

No, start form where you are currently and do AutoVE (which is a special case of Calc.MAFT) using CALC.WO2BEN from the Calc.VET thread

( noting that CALC.WO2BEN is defined as {GM.EQIVRATIO}*{EXT.WO2LAM1} ).

If you're not boosted then stay with GM OS.

Once you get VE corrected, try doing AutoMAF (which is a special case of Calc.VET) using CALC.WO2BEN... if it works out there is no reason to not run the MAF, but will require a straight section of plumbing before/after the MAF.

Yes, you can do CLSD... CL usually gives good low/part throttle driveability.

You can do DFCO and LC with the GM OS (need a cax for LC), but I don't reallt like LC (my $0.02).

I really didnt want to use the stock 80 mm maf considering I am running 102mm tubing and 102 mm tb.

Thats really why. So I guess I will go with AutoVE then.

[joecar]

Ah, ok, your MAF won't fit (for some reason I assumed you had a 100mm MAF), then go MAF-less.

[sac811]

Any particular reason why I should stick with the gm os over custom os going maf-less?

Figured it would make lean cruise and high/low octane tables better. Any negatives to custom os?

[joecar]

If you're running in CLSD then the COS's B3647 would not be being used much, so GM OS is good.

If you were running OLSD then the COS's B3647 would be used most of the time.

I like to get the GM OS tune dialed in, and then switch to COS and continue refining.

[sac811]

Ok, got everything going...kind of. The truck starts great, then dies a second or two after. If I hit the accelerator it dies quicker.

Does that mean it is getting too much GAS or too much AIR?

And either way, how do I go about adjusting for that?

Log of start is attached below

16219

[sac811]

Its looking like its WAY too lean, from my wideband, if that is the case how do I go about increasing the fueling so it doesn't die?

EDIT: I don't actually know if its lean or not, because I went and checked the wide band and it was showing rich before startup and lean at startup. Will reset in morning, but still need help from someone.

Is there anything special I need to do in the tune with no MAF being plugged in?

I've already got the tune from above changed to open loop, with MAF only enabled below 400 rpms, and all the other stuff needed for AUTO.VE.

Open Loop tune that starts but wont stay running:
16221

[joecar]

I think you will need to do some idle tuning.



Is there anything special I need to do in the tune with no MAF being plugged in?
Yes, make sure that a MAF DTC triggers immediately.



I've already got the tune from above changed to open loop, with MAF only enabled below 400 rpms, and all the other stuff needed for AUTO.VE.
Setting B0120 to 400 rpm means that MAF-only is used above 400 rpm, and VE/MAF is used below 400 rpm.

But with MAF failed (DTC present) B0120 becomes irrelevant.

[sac811]

I think you will need to do some idle tuning.

Yes, make sure that a MAF DTC triggers immediately.

Setting B0120 to 400 rpm means that MAF-only is used above 400 rpm, and VE/MAF is used below 400 rpm.

But with MAF failed (DTC present) B0120 becomes irrelevant.

Where do I go to set the DTC for the MAF failure immediately?

Also if that doesnt fix the vehicle being able to stay running, how do I go about idle tuning?

[joecar]

C6001: set the P0101, P0102, P0103 to either 1-Trip or Non-Emissions (do not set 2-Trip or Not-Reported).

C2901,3: set these to 1.


When you [attempt to] start engine you want a MAF DTC to trigger immediately.