pcmhacking.net

Hi everyone,

have been a member for a while now reading through all the posts on here and getting myself set up with the gear needed for tuning
I have a VY L67 manual that's running a flash PCM and i need a few tips as I'm stuck on a few things. I'm no expert on tuning so please excuse any stupid questions...

Bit of history, the car is a factory manual which had a NA motor. I changed the motor out for a rebuilt L67 item with a cam, LIM porting, head port cleaning, blower porting, ubend porting, 82mm pulley on the charger, LS6 maf. There are a few other minor things but thats the main stuff.
I had a kalmaker tune but having a go for myself with the enhanced gear from The1

The tune is quite good there are just a few small thing that i need to work on.
The car starts well cold but when hot it's a bit off and i believe that i will need to adjust the crank fuel PW Vs Coolant table ?

I have noticed that the IAC is high it will come down to about 50 when warm but not really go below this. I have checked for VAC leaks and found nothing also checked the the throttle body and the butterfly is 100% closed, currently running the one that came on my NA motor which has never had any changes made to the stop screw or anything like that Is this a issue??
I have tried a ported throttle body 68mm with about the same result
I also had a LS1 throttle body and had the same issue.

Another one is the DFCO. It will cut in but unless I'm off the throttle above 3000 RPM it will not cut in, even then it will still not cut in for a bit, then it will cut out at around the 2200 RPM mark.
The engine breaking is affected by this and the car will not slow down that much when i get off the throttle, im also looking to pick up some fuel savings by getting this a bit better
Here is a shot from the log. I have also attached a shot log if anyone wants to have a look Thanks for any help Peter.

Sounds Like you have it going in the right direction with the mods you have, good work so far & Yeah DFCO can be a bit difficult & time consuming, with the IAC try & get it to around 20 steps when at normal operating mode (obviously at idle closed throttle) & then work from there!
The TPS Throttle Gain % is your best friend there so it's at zero closed throttle & 100% when at open throttle! (a lot of changing back & fourth between test hence realtime----MASSIVE THANKS TO MODS HERE--- makes a big difference).

Thanks for the info VX L67 Getrag,

I'm not too sure on how to adjust the TPS gain tho, i found the scalar but not too what to watch so i know how much to change it by.
I take it ill need a to press the throttle to 100% but what do i watch while doing it??

also i think this might be false knock but worth checking i guess, noticed this below at the 0.22 mark when making changes to different tables what is a good amount to make a change by, i guess different tables will require different amounts..
I tried to adjust the cranking fuel by 5% but it didn't make much of a difference.

The weather has really prevented me getting the throttle body back on this week so I have spent a bit more time on the tuning side but have a few other questions.

When adjusting timing what is considered a lot of timing and what is the best way about making changes. I was reading the 12P guide and it talks about bumping it up 2 degrees at a time, there is also a history table which shows timing being removed. is this table likely to be the retard option in the history table ???

Also when using the injector multiplier tuning spread sheet it is scaled the same as whats in the bin and xfd (increases in 400rpm increments ) but the history table is in 200 rpm increments up to 2400rpm then above that its in 400rpm increments like the bin and xdf. Can one of these be changed so they are the same??

Peter

With the better knock control of the later pcms you can use knock counts and retard with a little more confidence than 12p. But the same principle applies with small timing increases.

The history tables can be adjusted/added to do whatever you want. Changing the axis breakpoints to match the xdf/bin definition is the way to go, the xdfs table size is fixed.

Thanks VL400

I will keep a very close eye on it then.

What would be considered a lot of timing ?? And is the only point that you will start to go backwards with torque and power is if the PCM starts to pull timing? assuming that you are adding fuel as needed.

Pete

Making some good progress (I think)..
Got the idle much better by increasing the timing and its much smother now which is nice while idling at the lights.

I do have one concern and that is the knock i got into days log, can someone have a look at this pic and let me know what you think I also need a bit of advice on the spark tables, my logs nearly always show less spark than in the spark tables even when i take into account the corrective spark for ECT Vs MGC and IAT Vs MGC.
Am i missing something here?

Peter

Sounds like you have it idling a lot better!

In regards to it commanding a lot less than hi oct table it could be IAT & ECT modifiers & there is well defined items in the adx to see where it's coming from!
It could be more than likely mainly running low oct with the counts your seeing for knock, but no one can remote tune that safely as you need to know if it's actual knock or noise that can be ignored & can tune to suit if it's just false noise!

Thanks VX L67,

If it is using the low spark table does the PCM work its way back to the high table and if so how does it do this?? time elapsed...
I guess that if its using the low table and the IAT & ECT's are close to the max they could be pulling 10 degrees also. I'm close to the max for the IAT as i dont have a cooler yet..

Had a look at the log and all the counts are at or below the 2500 rpm mark so whats the best way to look at this then add fuel or remove spark or do you need to do a combination of both ?

Peter

Yeah if it's learnt knock it will learn if it's not seeing knock & go back to hi oct eventually if it stops seeing events!
But you need to make sure it's not ACTUAL knock events!

You really should re-read through all the guides, but if you want to change it from picking up knock events when it's not actually knocking you need to add ignore in that area where it is & reset PCM!