Turbo G8 (E38) tps stays up, RPM falls, and MAP takes off

[Tferrellsn95]

I am at a complete loss on this car. I need advise where to look and if this is even tune related at all. The car is a 2008 G8 GT. I wrote a Holden 6 speed OS because I ditched the 6l80 TCM then applied the 2.5 bar OS and speed density patch because the MAF is completely out of the picture

Engine: 408ci cast block (gen 3), hand ported ls3/l76 heads, BTR cam kit and stock LS3/L76 intake. Turbo is a FI billet T4 S480. FIC 1200's, twin 340 in tank pumps. Secondary is activated by a Hobbs switch at approximately 4lbs (verified).

Transmission: TH400 reverse manual VB and Cameron convertor

The issue is when MAP goes beyond 169-170ish kpa, the car sputters violently. It sounds exactly like RPM's are being limited except it seems to be more load related because I have achieved 6,000+ RPM in low gear while 2nd sees less than 5500 and high gear will stop around 5k. Whats odd to me is MAP pressure shows an increase while RPM falls and TPS stays steady. I thought spark was being blown out so I put new plugs in it and tightened my gap down. I thought maybe the wastegate controller was causing the issue ,despite arguing with myself this has to be spark or valve train related because the frequency is so high when the condition occurs, so I took the controller line off my WG and upped springs to 15 lbs. The AEM truboost shows a max of 14.7 psi across the entire log I am attaching. I will admit the tune is very rough. I have been chasing this issue for over a week and dedicated all my spare time to fixing this stupid issue. Thank you in advance!!

[jsllc]

So mis-fire is horrible. Tune should not be run this hard until you have the SD cleaned up. Some very lean spots for boost then spots where .62 lambda which would be low 9s on pump gas. Mis-fires could be mechanical but until you running in the 11s or .83 lambda could be all fueling.

[jsllc]

What pressure are you running the fuel system at? I assume it has a return? Is it a manifold/boost referenced regulator?

[Tferrellsn95]

Fuel pressure is at 55 psi. This is a return system and boost/vacuum referenced. This is E85. PCM calculated 77+% ethanol. I agree with not running it this hard but I didnt know how else to figure out the issue. Is there a misfire counter I dont know about or how did you see that?

[ZincGT]

This is scary

ve table.jpg

[jsllc]

This GM is a 4bar system so should be 58 lbs at idle. The misfires are easy. They are in your log. Your fueling is going what you command. VERY BAD.

7-11-2019 11-06-57 AM.png

[lukearmstrong1990]

OK.... before doing anything START AGAIN!!!

most of your issues will be likely from your VE table number being way too small and the torque calculations being miles out making the PCM do weird things.

first of all double stoich, halve the IFR and redo your VE table!!!

and sort your spark tables out!!! base advance of negative with corrections all making it a positive.

[lukearmstrong1990]

1019rwhp_17psi 807rwhp_12psiP2068.hpt

see attached file as example. note VE table values, AFR term, stoich and the injector flow rate not maxed out. the logs I didn't save also show it using far more resolution for spark due to the correct airflow model, unlike yours. it also pulls to 7000rpm no worries

1600cc injectors, fulltime E85, decent camshaft, TH400. 400cubes S480 T6 single.

[Tferrellsn95]

Thanks for the help guys. I'll get to work on the VE first and go from there. I used the ERM tools to scale the tune for the 1200's using the data supplied with them but I may have input some of the data wrong. ZincGT, your screenshot is of IMRC closed. I was under the impression I was to use the IMRC open table. Is that not correct?

[ZincGT]

Make all 3 the same