Ve ssv ute running rough, misfire flat spots

[SSVREDLINEUTE]

I personally do think it's the coils, but holden have stated they have tested them. I've got four including the ignition module coming from the states to test myself.. As one of the coils is 200ohms where the others are between 60 to 70 ohms.. I've tested the leads.. And in particular one is 100 ohms. All the others are 30ohms.. I'm no expert at this.. So I'm not entirely sure what this will prove..
The car runs really well on premium with just a slight miss.. but I miss the power from flex. On flex it makes 290kw at the wheels where as on premium it makes 260kw huge difference.. This is caltex e85.
I'm going to flush the flex with another tank of premium then I'm going to try united flex to see if it is the fuel. From caltex..my car is designed to run it.. And I have it tuned on a mainline dyno by willall racing.. If it plays up again.. On flex I might go back to willal to get their advice... I've been chasing this missing issue since the life of the car 2011.. It's p@ssing me off

 

[kingyinperth]

I personally do think it's the coils, but holden have stated they have tested them. I've got four including the ignition module coming from the states to test myself.. As one of the coils is 200ohms where the others are between 60 to 70 ohms.. I've tested the leads.. And in particular one is 100 ohms. All the others are 30ohms.. I'm no expert at this.. So I'm not entirely sure what this will prove..
The car runs really well on premium with just a slight miss.. but I miss the power from flex. On flex it makes 290kw at the wheels where as on premium it makes 260kw huge difference.. This is caltex e85.
I'm going to flush the flex with another tank of premium then I'm going to try united flex to see if it is the fuel. From caltex..my car is designed to run it.. And I have it tuned on a mainline dyno by willall racing.. If it plays up again.. On flex I might go back to willal to get their advice... I've been chasing this missing issue since the life of the car 2011.. It's p@ssing me off

30rwkw difference you say..s*(t eh? what mods have you got if I may venture a little off the specific issue..ps I think yours(and mine)are an l98 motor being manual.

 

[PIR4TE]

Possibility of either at the end of 2010 / start of Series II manual.
As posted in a previous thread, your MAF tables seem scaled out of usable frequency range for the LS2 style MAF, symptoms point to lack of usable resolution. Only good to 300 g/sec really (280rwkw). There are work arounds to resolve this.
Also interested to learn more detail about your mods to achieve 290rwkw and what was the outcome with the u/d?

 

[SSVREDLINEUTE]

It's the 2010 oct series 2 l77 manual.

 

[SSVREDLINEUTE]

Possibility of either at the end of 2010 / start of Series II manual.
As posted in a previous thread, your MAF tables seem scaled out of usable frequency range for the LS2 style MAF, symptoms point to lack of usable resolution. Only good to 300 g/sec really (280rwkw). There are work arounds to resolve this.
Also interested to learn more detail about your mods to achieve 290rwkw and what was the outcome with the u/d?

I'm not sure what u mean maf tables..
Please go into more detail also 300g sec??

Ok: mods
3 inch straight through exhaust, pace maker tri headers 100 CPI cats. No mufflers. Only j pipes at the end and otr. The tuning was done by willal racing on a mainline dyno. I've got the sheet to prove it. It's maf to by the way

 

[SSVREDLINEUTE]

Also this elite catch can, does it really smooth the idle?

 

[kingyinperth]

It's the 2010 oct series 2 l77 manual.

cheers mate the numbering of models baffled me a little early doors,..
Bloody good gains on the e85 then...not sure if practical where I am to source the fuel but has got me interested for next time I tune mine..subject to it still running well I guess as per your ongoing issue.
My mods similar(minus headers) so new OTR im getting + add 1 3/4 4 into 1 headers,tune on e85 might see me in the very high 200's rwkw too(at 252 atm).

 

[PIR4TE]

Ok, good result, puzzles me how tuners claim that is accurate without forced induction or adding lift / duration.
You see 290rwkw peak is 103.5% of the stock volumetric efficiency of our engine, so it doesn't matter how well your bolt-ons flow - the dynomometer reading appears incorrect. Yes, would like to see the printout thanks.
Anyway regarding the misfire, a 290rwkw MAF-centric L77 tune is bound to run rough because you are pushing the physical limit of the LS2 MAF's ability to provide an accurate measurement of air mass flow, critical feedback for the tuning of the ECU.
In more detail, the MAF's coldwire sensor is part of an oscillator circuit whose oscillation frequency changes with sensor inductance; hence the frequency correlates to actual air passing over the unit.
The ECU interprets air mass flow (in grams per second) according to the sensor's frequency (hz) using a table of values. This can be 'fudged' or 'scaled' to enable non-stock air mass flow to be reported to the ECU, however the table's frequency axis is finite, meaning incremental changes in air mass are not as accurately reported as stock.
The other factor affecting the tune's accuracy when scaling MAF over 280rwkw is the size and design of the MAF housing and its ability to cope with reporting actual air mass 300-320 grams per second with reliable resolution, due to issues of laminar flow / smoothing turbulence.
Typically modified engines above 280rwkw are tuned using speed density (MAFless) to overcome the difficulty, or utilise a larger 100mm+ MAF card and housing from an LS7.

 

[SSVREDLINEUTE]

They were surprised with the result too. I'll try and load the graph tonight.

 

[SSVREDLINEUTE]

cheers mate the numbering of models baffled me a little early doors,..
Bloody good gains on the e85 then...not sure if practical where I am to source the fuel but has got me interested for next time I tune mine..subject to it still running well I guess as per your ongoing issue.
My mods similar(minus headers) so new OTR im getting + add 1 3/4 4 into 1 headers,tune on e85 might see me in the very high 200's rwkw too(at 252 atm).

It's amazing how much more power you get from it.. But one bad batch of it your car runs down likes broken 4 coils. I'm going to flush it and try another petrol company and see if it's caltexs e85 fuel. I definitly recommend it the power you can achieve from that fuel is worth it. I'm going to update the post once I've flushed and used united flex..