HSV Maloo Ute with CamTech 285 Cam - Stumbling on take-off

[MadPanda]

Hi Guys,

I am fairly new to HP Tuners and GM Tuning (my main tuning knowledge is in EVOs and WRXs). I have been learning a lot though on my LS3 swapped Toyota 86.

A friend with an HSV Maloo (LS3 with 1,7/8 long tube headers and Camtech 285 cam, (specs below) He has taken it to multiple tuners who incidentally gain power for him but his tip-in seems stuffed. When releasing the clutch to take off with match gas pedal the engine stumbles and almost stalls (occasionally it has). I got a log of it and you can see some weird behavior in it (he takes off from stand still 3 times in the log).

Can someone take a look and tell me what they think it is? It looks like it pulls heaps of timing just off idle and and the o2 sensors look like they lean right out. The car performs perfectly once moving. His tuner wants him to drill a bigger hole in his butterfly (currently 10mm) and he would like some advice and I would like to learn. He is on a SD tune. I have tried some small things like spark smoothing to no effect. I would like people who are better versed in GM tuning to point me in the right direction.

Cam Details:
Part No: CT287149906
Description: Our most popular cam in stock or modified engines. Brutal mid range and top end. Requires 3.9:1 diff ratio, good exhaust & custom tune. RPM RANGE 2600-7000
Specs: 285˚ 285˚ 233˚ 233˚ .591" .596" 113˚
Link to Product: http://www.camtechcams.com.au/chev_sb_gen3_rollhyd.html

Log: Pat's Maloo Oztrack Tune Log XX.hpl
Tune: Pat's 2010 Maloo 6.2lt oztrack12.hpt

Thanks in advance guys,
Camo

[07GTS]

my cam is basicly identical to that one but 114lsa, it dosnt need a hole in the TB (10mm jees), u still have some TM which could affect it, also its not set to SD properly should have the 3 maf DTC to mil on first error and maf frequency fail hz are wrong should be high 2 and low 1, and maf test rpm and high counts thresh set to 1 so it fails quicker

[Area47]

excuse the language with this. Why the fuck did someone drill a hole in a drive by wire throttle body!?!?! there is a pretty big swings in the timing side of it.

[MadPanda]

Thanks for your help guys, if anyone else has ideas please post, like I say I am learning and want to just help out a mate because it seems he has spent far too much and not gotten a drive-able vehicle back and really whats the point of all the power if you have anxiety about taking off in the car.

my cam is basicly identical to that one but 114lsa, it dosnt need a hole in the TB (10mm jees), u still have some TM which could affect it, also its not set to SD properly should have the 3 maf DTC to mil on first error and maf frequency fail hz are wrong should be high 2 and low 1, and maf test rpm and high counts thresh set to 1 so it fails quicker

Yeah I am not sure why physically drilling the throttle over adjusting the tune is necessary. However I have read plenty of threads on various forums where this seems to be debated regularly on LS engines. I will adjust those settings and give it a try.

excuse the language with this. Why the fuck did someone drill a hole in a drive by wire throttle body!?!?! there is a pretty big swings in the timing side of it.

Yeah the timing swings are what I noticed and I am yet to determine if they are the cause, because his timing tables seem to be okay. I am trying to work out if its the timing tables, another table altering the outcome, or an outcome due to an event in the engine.

[MadPanda]

u still have some TM which could affect it

What Torque Management settings do you believe are still active? It all looks disabled to me?

[07GTS]

tip in fuel/spark cut and some in that area

[BigDaddyCool]

Tune looks alright.......

Have you guys turned off the traction control button and done a few digs to see if it still pulls timing? Traction control is set to pull spark in that tune.

Hi Guys,

I am fairly new to HP Tuners and GM Tuning (my main tuning knowledge is in EVOs and WRXs). I have been learning a lot though on my LS3 swapped Toyota 86.

A friend with an HSV Maloo (LS3 with 1,7/8 long tube headers and Camtech 285 cam, (specs below) He has taken it to multiple tuners who incidentally gain power for him but his tip-in seems stuffed. When releasing the clutch to take off with match gas pedal the engine stumbles and almost stalls (occasionally it has). I got a log of it and you can see some weird behavior in it (he takes off from stand still 3 times in the log).

Can someone take a look and tell me what they think it is? It looks like it pulls heaps of timing just off idle and and the o2 sensors look like they lean right out. The car performs perfectly once moving. His tuner wants him to drill a bigger hole in his butterfly (currently 10mm) and he would like some advice and I would like to learn. He is on a SD tune. I have tried some small things like spark smoothing to no effect. I would like people who are better versed in GM tuning to point me in the right direction.

Cam Details:
Part No: CT287149906
Description: Our most popular cam in stock or modified engines. Brutal mid range and top end. Requires 3.9:1 diff ratio, good exhaust & custom tune. RPM RANGE 2600-7000
Specs: 285˚ 285˚ 233˚ 233˚ .591" .596" 113˚
Link to Product: http://www.camtechcams.com.au/chev_sb_gen3_rollhyd.html

Log: Pat's Maloo Oztrack Tune Log XX.hpl
Tune: Pat's 2010 Maloo 6.2lt oztrack12.hpt

Thanks in advance guys,
Camo

[MadPanda]

Tune looks alright.......

Have you guys turned off the traction control button and done a few digs to see if it still pulls timing? Traction control is set to pull spark in that tune.

Funny you mention that because I asked my mate to do a few runs without traction control and to let me know. Just waiting for feedback. I also think retaining stock traction control (ie ETC enabled) would be better. I should know more shortly.

[MadPanda]

We test drove with and without Traction Control and it made no difference and still stumbled on take-off.
The MAF and DTC adjustments didn't make a difference either.

[07GTS]

in your main spark table where u have the 1600-2000rpm and up to 0.20 g/s keep that trend going down to zero and then blend it down to the 0.48 g/s range, so u are basicly increasing that whole range by 10+ deg, u should log cylair and dynamic air they help and u cant see where your spark is without it in the tables, see if that helps with the timing mine is a little higher then that and mine dosnt drop at all and helps with straight off idle clutch release

[MadPanda]

I will give that a crack and see how I go, thanks again.

[BigDaddyCool]

Did you sort this out? I was going to say watch your timing and log adaptive idle timing to see if any gets pulled causing the stumble.

[MadPanda]

Still have this issue actually. Tried just about everything. But I am lucky cause the bloke is a good friend and is patient with my learning. Once I crack it, I will be a happy man 😂

[Ben.]

I don't have the experience of a lot of other guys on here, but here's my 2c:

Those timing swings are huge. For a start, cut back your idle under/over speed tables. As a test, make it say... 0 degrees in the first couple of cells, 1 degree in the next, then 2 degrees in the cell after, then 3 the rest of the way.

Then, try to make your idle ignition timing tables the same as your main timing tables. At the moment, your main tables have an extra 10 degrees of advance at idle, I'd say this might be plaguing you. Just looking at the tune, not the log, you can see its going to target about 18 degrees at idle, then swing up to 24 or 28 degrees either way because of the idle under/over tables. As the clutch is engaged and the car starts moving, it will see an RPM drop, add a heap of timing to try and get it back to its target value, then as the throttle is applied it will cut over to the main tables, suddenly increasing the ignition value from a target of 18 to 28.

Edit your main ignition timing tables so you have 18 degrees around idle (as you do in your idle tables), and blend them out into you actual 'drive' timing numbers. once you've done that, copy the RPM columns from the main timing map into the idle timing map. Pay attention here as the scales are different on the two.

After all this, you should have your target value as it is in your main timing map, and idle controls tweaking it no more than 3 degrees either way. I didn't look up the specs on the cam, so you made need a little tweaking here and there, but try the above and see if it at least helps smooth it out.

edit - another little thing I do is sometimes add a bit more timing at idle, even slightly more than is desirable so that there aren't any major steps in the timing as rpm increases. EG, if 18 degrees is your 'sweet spot', where you adding more timing doesn't help vacuum, I might push it out towards say... 22 degrees or more, so that I can ramp in timing gradually as RPM increases. If you leave it at 18, you might need to put 21, 24, 27, 30 in the next few cells. I'd start at 22,23,25,27,30 or so. This can help smooth out light throttle, cruising conditions a fair bit.

[07GTS]

just get to know what spark and spark correction tables are being used and when, then u know what to look at to increase or decrease ect, it might be a bit funky but i kept main spark normal and idle spark table as all 18 then set all others idle coastdown and the spark correction all to different numbers for example idle coastdown all 25 all coast correction all 5 except zero rpm, all gear correction all 3 and so on so then when u go for a drive u can see exactly which table is in use and when, even when ur above adaptive idle the airflow/spark correction are still in use but won't be shown in adaptive spark pid so this just helps show what's going on