Few tuning questions

[VX-SS-383]

I have an ls1
With 232/234 cam cnc heads 78mm tb
Running bosch 42lb injectors
Im still working on the tune
Idles great but stomp on it and its pretty average.
Im wondering if adjusting anything in dynamics b3426 and b3428
will make any difference.
I have a log here if that helps.
Its running a mafless tune,any feedback is appreciated.

[joecar]

Did you edit the injector tables using data for those injectors...?

Is your FPR manifold referenced or un-referenced (determines whether the IFR table is flat or sloped)...?

Did you correct the VE table...?

Post your curent tune file.

[VX-SS-383]

Its unrefrenced ,dead head system
Its had a new fuel pump assembly installed
as i found a split o ring on the fpr on the old unit.
It starts idles and drives good,ive noticed though
its running richer up top which i expected and
i do get wheels spin in 1st but its now
developed a miss under wot.
Im thinking it may be o2 sensors.
Before this issue though it always seems to struggle
in the upper rpms-just feels a bit flat.
Has a turbo 400 with 4500 stall and 3.9 gearing.
I did a log yesterday and filled up,i always run bp ultimate 98 octane.
The tune still needs works but im still learning so open
to suggestions on how to improve the tune and things i could have missed.

[joecar]

Dead head (i.e. does not even have an un-referenced FPR returning fuel to the tank) is not good, it allows the pressure to peg...

and it will over-pressure your fuel system causing it to leak, and drastically shortens the life of the pump...

measure rail pressure, you will see it peg at 70+ psi...

so your IFR table will not match what your injectors actually flow at 70+ psi;


you want rail pressure to be as follows:
- un-referenced FPR: 58 +/- 1 psi.
- MAP-reference FPR: 58 psi +/- 1 psi (with reference hose temporarily removed).

[VX-SS-383]

Its got a reg in the bucket assembly its just stock.
Nothing aftermarket with the fuel system apart from the bosch 42lb injectors.
Pressure is fine now,it was bleeding off before due to a split
o ring and the whole unit looked average so i put a whole
new unit in the tank.
Cars a vx ss commodore 2002.
It would take a 1-2 goes to crank now it starts 1st go.
Does the ifr table look ok?
I used the spreadsheet and thats what it came up with
and seems to be working,its been tuned and running
well but i think i can improve on alot.
Just was curious about dynamics and how some of those settings
can afftect the tune.
Atm its rich up top around 12:5 on the wideband since putting in the new fuel pump.
Idle and cruise seem ok.
It just feels like it dumps in too much fuel when you go to full throttle quickly.
On back off ive seen afr in the 11s the it goes back to normal.
I also supect my o2s are gone as its now missing under full throttle.

[limited cv8r]

The commodores run a returnless fuel setup (not dead headed).
You are running an open loop mafless tune, so your o2's should have no effect. 12.5 at WOT is pretty much what to aim for, for a safe tune.
It may help if you post up a log of your problem (eg going WOT) instead of a cruise down the highway.

[joecar]

Ok, so it's not dead head, it's "returnless" meaning the FPR is un-referenced (actually barometric-referenced) and lives in the bucket.

I'll be able to look at your files later today.

[limited cv8r]

You are also running a COS but have high and low spark the same?
Is this your tune or one you have found and used as a starting point?

[joecar]

General comments:

Set A0012,13 to max-1.

The 105 kPa columns of B0101 Main VE and A0009 Boost VE are different (i.e. VE has a step transition).

A0009 Boost VE doesn't seem right (and looks too smooth).

B3609 can be set to 0.01 s.

What is the lean trough in B3647 from 1200-2000 rpm below 65 kPa...?

Note that in B3647 the cells that are 1.00 EQR (stroich) will cause semi-open loop trimming (using STFT's)... during tuning you don't want this, you can disabled it by making those cells non stoich (by at least 1%).

B3618 is too restrictive above 3200 rpm... set that portion to 35%.

Did you get values for the injector tables (voltage pulsewidth adjustment, small pulse adjustment, minimum pulsewidth...)...?

B4001 looks to be calculated ok based on heptane test fluid (what they use to flowrate the injectors)... so maybe multiply the IFR by 1.03 (since octane is about 3-4% denser than heptane)... but it is close enough as is (based in calculation).

CL is disabled (B4205) but trims are enabled (B3801)... disable trims.

HO and LO spark tables are identical, like cv8r said.

[VX-SS-383]

The 105 kPa columns of B0101 Main VE and A0009 Boost VE are different (i.e. VE has a step transition).

A0009 Boost VE doesn't seem right (and looks too smooth).

*Didnt realise anything was there,does it even use this table?car is n/a

B3618 is too restrictive above 3200 rpm... set that portion to 35%.
*Might seem silly but what do you mean by 35%? set it 35% higher or lower?

*Ive fixed everything else that you mentioned.
With the spark map im pretty sure it only uses the low octane map
any when your mafless? i just modded the high octane
and made the low octane identical or should they be different?

I also did a log and P0336 came up crankshaft position sensor,its missing quite bad under 80-100% throttle.

Ive attached a log,couldnt really give it much it would just break down
and throw the cel on.

[VX-SS-383]

Btw this was a maffles tune i bought with a pcm
so havent gone through everything.
The tuner i used previously had locked my pcm
So i just got another one and sold my original.
At the time it had stock,tb,injectors and small 1-5/8 primary pipes
same cam and heads etc.

[VX-SS-383]

Found the crank angle sensor issue,
The harness was squashed between the block and heat shield
against the headers,exhaust shop must have done it
when i had the 4 into 1s installed ,been like that for a while too.
Just repairing the harness now.

[joecar]

see my responses in red:


A0009 Boost VE doesn't seem right (and looks too smooth).

*Didnt realise anything was there,does it even use this table?car is n/a
If you don't have boost then ignore A0009.

B3618 is too restrictive above 3200 rpm... set that portion to 35%.
*Might seem silly but what do you mean by 35%? set it 35% higher or lower?
The table is TP with units %... above 3200 rpm set it to 35% (look at 2002 Camaro file for example).

*Ive fixed everything else that you mentioned.
With the spark map im pretty sure it only uses the low octane map
any when your mafless? i just modded the high octane
and made the low octane identical or should they be different?
COS's enable adaptive spark when MAF-less (i.e. spark timing slides between HO and LO tables according to presence/intensity of knock).

I also did a log and P0336 came up crankshaft position sensor,its missing quite bad under 80-100% throttle.

Ive attached a log,couldnt really give it much it would just break down
and throw the cel on.
I'll take a look at your log later tonite.

[joecar]

Found the crank angle sensor issue,
The harness was squashed between the block and heat shield
against the headers,exhaust shop must have done it
when i had the 4 into 1s installed ,been like that for a while too.
Just repairing the harness now.Take a new log.

[VX-SS-383]

Thanks joecar,i fixed the missfiring issue.
All good now,so i can sought out the tune now.
Ill load those changes and get another log today.

[joecar]

Ok cool :cheers: let us know how you go.


How did you fix the damages CKP sensor harness...?

[VX-SS-383]

Removed the heatsheild completely as it wont fit properly
with the huge 1-7/8 4 into 1 headers- ceramic coated headers anyway.
It had just cut the insulation enough to ground out on hard acceleration.
Used some electrical tape and flexable conduit to insulate it.
The old conduit just crumbled away.
Very happy i found it and fixed it for $10.