SD LS9-boosted E40 hitting REP

[Hydra Performance]

Hey guys,

We've been running an SD-only E40 on our drift car for years now without issue. When I swap out the LS3 intake manifold & injectors for an LS9 blower setup with 100lb injectors the car runs well long enough for me to be able to tune it, i.e. a few isolated WOT pulls, but after thrashing it for a couple min it will eventually go into REP mode without throwing any codes, a condition which is cleared by simply turning the car off & on again. I suspect there is some sort of limiter/nanny somewhere that is tripped after a certain number of counts, and that the rescaled tune is what's causing it. P0068 has been moved out of the way and ETC TPS Max (#12850) has been maxed out as well. I even tried setting the Reduced Power Mode (#33034) map = to the Normal mode maps, but that made no difference either. I can tell you its not a TB issue because a) same thing happens when we swap it out for a brand new one , and b) no such issues when running the engine NA with an unscaled tune. Should I play with the Engine Diag -> Airflow -> TPS tables? Should I disable 1516 and 2101 altogether in the DTC section even if no codes are being thrown?

I have attached the file & the log, any help would be very much appreciated

E40 drift PCM hydra 2023 ZR1 98RON 28T COG offset TEST.hpt
fault3.hpl


PS - For the rescaled tune I didn't do the usual 50%, because I wanted to maximize resolution. Set the injector size to the max allowed 8 g/s and multiplied the VE table by ~65% of where it should be for everything to fall in line, could this be it?

[blindsquirrel]

Yeah, that's not at all how you scale for bigger injectors. All you have to do is double Stoich, half IFR, half AFR Term. Resolution isn't an issue, the VE should be unchanged.

You also still have the default placeholder values for MAP linear/offset that gets auto-filled when you do the 2-bar OS.

Did you or somebody change the Open Loop & Open Loop Gains tables, from 10 x 0.1 style to 1 x 1? I don't have a stock file with your same OS ID, but all the other OSes I have here are 10 x 0.1.

[blindsquirrel]

MAF is not properly failed, either.

[Hydra Performance]

Thanks for getting back to me, I have attached a copy of the stock file off this PCM. As you can see the OL Gain tables are untouched, and we're running a 2-bar MAP sensor so the values should be correct. I realize the MAF hasn't been "properly failed" but its been running like this without issue from day 1. You think the way I did the injector scaling could be the reason for the ETC Reduced Power flag being tripped?


E40 drift PCM base.hpt

[edcmat-l1]

The .hpt posted in the OP is not an SD-only tune file. The MAF isn't failed at all. You're running in MAF mode. You're probably going into limp mode because you're pegging the MAF. You can run it in MAF mode just apply the MAF patch. That'll extend your table out to 15K hz.

[blindsquirrel]

Which P/N MAP has correct linear/offset of 200/10.33? It's not the DPE 2.5, and it's not the Cobalt BARO sensor. Either you have a unique sensor, or the settings never got changed after the OS changed it for you.

Your comment dismissing the MAF fail settings is like if somebody pointed out your leg was broken, and you responded with "oh, that, yeah but it don't hurt none, it's OK".

[Hydra Performance]

Gents,

The car has no physical MAF sensor installed, been running this way, with those MAF fail settings, for 4 years now. I will try setting MAF to 1/0 Hz but I very much doubt it will change anything. We're running a GM 2-bar MAP sensor, PN 12580698 , so those settings are correct

[gtstorey]

I went through an several rounds helping someone try and use MAP 12580698 a few months ago and were unable to get anything to work for it. I don't know if there is some mistake in the industry cross reference charts but he was unable to get 200kpa/5v and an offset of +8kpa to work. He eventually got a GM sensor 12615136 to work with the 200 and 8.

https://forum.hptuners.com/showthrea...light=12580698

[edcmat-l1]

Gents,

The car has no physical MAF sensor installed, been running this way, with those MAF fail settings, for 4 years now. I will try setting MAF to 1/0 Hz but I very much doubt it will change anything. We're running a GM 2-bar MAP sensor, PN 12580698 , so those settings are correct

OK, not trying to be a dick but that's different than "This is a SD only tune file we been running". It is not setup correctly but if the MAF is unplugged it has to be failing.

Anywho, your P1516 is set to no error reported. Betcha turn that back on and it sets when you go into REP.

Carry on..........

[Hydra Performance]

OK, not trying to be a dick but that's different than "This is a SD only tune file we been running". It is not setup correctly but if the MAF is unplugged it has to be failing.

Anywho, your P1516 is set to no error reported. Betcha turn that back on and it sets when you go into REP.

Carry on..........

I appreciate your help, I really do.

The P1516 disable was a last-gasp addition which made no difference. It wasn't tripping that code even before I disabled it


E40 drift PCM hydra 2023 ZR1 98RON 28T COG offset.hpt



One other interesting thing I noticed, was that PCM Voltage would decrease ~1V AFTER the "ETC Reduced Power" flag was set, you can see this happening at the very end of the log I posted in the OP

[edcmat-l1]

I appreciate your help, I really do.

The P1516 disable was a last-gasp addition which made no difference. It wasn't tripping that code even before I disabled it


E40 drift PCM hydra 2023 ZR1 98RON 28T COG offset.hpt



One other interesting thing I noticed, was that PCM Voltage would decrease ~1V AFTER the "ETC Reduced Power" flag was set, you can see this happening at the very end of the log I posted in the OP

I would start by turning that code back on. Then set your P2101 and P1516 % to something like 20 or 25%. Then see what it does. If it still does it, I'd wipe it clean with an MDI and start over with some values that looks like they make sense.

[STAGEUP]

Re-enable P1516, then you need to add slave segment data through the VCM editor, add to the P1516 threshold throttle percentage (start with 25%) in engine diagnostics, save it, and "Write Entire" . Done

[blindsquirrel]

I dislike the 'magic bullet' style of diagnosis, trying to find the one single thing that fixes only the one single immediate problem. Too often things are related in unexpected ways. Fix the obvious problems first.

The injector scaling is wrong. The MAF is failed wrong. The MAP linear/offset is wrong. There is probably more, but after finding those fundamental basics being wrong I kinda stopped wasting time looking for more. I think those things should be corrected and then see where you stand. You'd at least have eliminated a bunch of unknowns that are otherwise impossible to rule in or out as possible causes.

[blindsquirrel]

Re-enable P1516, then you need to add slave segment data through the VCM editor, add to the P1516 threshold throttle percentage (start with 25%) in engine diagnostics, save it, and "Write Entire" . Done

Never yet seen an E40 file with the 'add slave segment data' feature.

[blindsquirrel]

12580698/12615136, the stock replacement Cobalt SS baro sensor, is 200.00/8.00. His file just never got changed from 200/10.33 after the custom OS was applied. But he's not interested in changing anything unless it can be proven beforehand to be the exact cause of the REP, so... deaf ears.

[gtstorey]

Trying to cross reference the maps can get tricky, but the LSJ (cobalt SS-SC) file has linear 270.59and offset of -3.30. Cobalt SS-NA has linear 94.43 and offset of 10.34.

[blindsquirrel]

That's the MAP sensor. Linear/offset for the BARO isn't shown anywhere in the tune file.

E40 can't accept a linear value greater than 256kPa, and offset can't be a negative number. Which is why the BARO sensor gets used instead.

[gtstorey]

That’s why the cross reference was so hard to follow.

[blindsquirrel]

https://www.rockauto.com/en/moreinfo.php?pk=10061124

[gtstorey]

https://www.rockauto.com/en/moreinfo.php?pk=10061124

Yes, you said baro sensor but I forgot that the earlier Cobalts had the separate sensor. My later model doesn’t have a separate sensor for baro, it’s built into the ECM. It does have two separate map sensors though.