LS3 434 E40 surging

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I'm having some issues with my build that I want to try to sort out before I take it to another tuner. I have an ls3 based 434 in my Chevelle running off an 05 gto e40 ecu. The issues I have are surging when coming to a stop and hard starting while cold, I have to give it a lil gas or it'll die after starting. The car also seems a lil hesitant below 4000 rpms. Most of the issues came after the NW 102 tb. The car drove better with the factory 90 tb. I've also installed 60lb injectors today I have been using the factory 42lbs for over a year now.

Here are the mods done to the engine.
Re-sleeved ls2 block. 4.155 bore
11.7 dynamic compression
FIC 60lb injectors
241/250 .630/615 114 +3
280cc ls3 heads ported by advanced inductions
fast lsxhr intake
NW 102 TB
arh 2 inch headers
t56 magnum

I'll upload my tune, modified for the 60lb injectors, a log file, and a copy of the injector data if anyone wants to look it over for me to see if I made a mistake.
Quentin Lawrence 2005 GTO M6 434 LS3 heads inj 241-250-114 BIG MAF 102TB PG tune 60lb.hpt7_21.hplFIC630CC-60LBBOSCHEV14LSXHPT.xlsx

[Lakegoat]

I am pretty sure that your MAP sensor data is incorrect. Look at the part number and get the correct info. Do you have a returnless fuel system at 43# or 58#? Base running airflow chart should not be one number. You need to modify your spark tables and startup fuel. I'll post some of the changes---give me a few. Big thing is map

[Lakegoat]

Is there some reason that you used numbers from the scaled version on the injectors? You can double stoich, half ifr, half ivt terms to get below the 63.5# limit. Since your are NA, you don't have to worry about the 1.36g limit on spark.

[Lakegoat]

Your TB shouldn't give you problems as long as you tuned for it when you installed it. ETC scalar should be close enough. Are you trying to tune this or just getting ideas for your tuner?

[[email protected]]

I'm running the stock ls2 map, part# 16212460. I'm running a return style fuel system with an adjustable fpr mounted near the rail.

[[email protected]]

No, I must have copied from the wrong table,

[[email protected]]

Your TB shouldn't give you problems as long as you tuned for it when you installed it. ETC scalar should be close enough. Are you trying to tune this or just getting ideas for your tuner?

I'm trying to tune it myself for now, my tuners is backlogged for q couple months and 400 miles away.

[Lakegoat]

I looked up the Map sensor on sloppy mechanics. Linear should be 94.43 and offset is 10.34. I think the middle number is 33.00. All the things that are wrong are going to require a retune of a lot of things. If you have a return fuel system, the ifr numbers will be constant across the chart as well as the vac chart.

[Lakegoat]

Here are some changes that should help with the surging and hard starting AFTER you fix the other issues.

[[email protected]]

I looked up the Map sensor on sloppy mechanics. Linear should be 94.43 and offset is 10.34. I think the middle number is 33.00. All the things that are wrong are going to require a retune of a lot of things. If you have a return fuel system, the ifr numbers will be constant across the chart as well as the vac chart.

I re tuned the car last night with the stock map sensor data which matches what you posted above. I also retuned for the injectors and doubled the stoich, half ivt terms. I took the car for a test drive and it starts better and 95% of the cam surge is gone. Car is still a lil rich wb reads 12.2 @ wot, but it is much better.Quentin Lawrence 2005 GTO M6 434 LS3 heads inj 241-250-114 BIG MAF 102TB PG tune 60lb_rev2.hpt7_2.hpl

[Lakegoat]

You still have wayyy too much base running airflow at idle. It is driving down spark way below what you wanted at 18 degrees. What does the map sensor read at key on---engine off now?

[[email protected]]

Here are some changes that should help with the surging and hard starting AFTER you fix the other issues.

I applied some of the changes you suggested, car starts up on the first try now and most of the surging and bucking is gone. I think the biggest change was correcting the map sensor. Now I have to work on the idle, it's too rich.

[Lakegoat]

Let us know how it turns out

[[email protected]]

Made a quick run with the suggested changes. Car idles perfectly from a cold start, so far this is the best I've seen the car idle since I built it. The only issue I have now is that coming to a stop the car struggles to idle again, the rpms drop too low and the car is about to stall out. I may need to modify the idle airflow a bit. Other than that the car runs stronger than before with no hesitation below 4000rpm like it had before. Here is the current tune and log file.

log 7_3.hplLS 434 Rev 2 suggested changes-airflow idle.hpt

[Lakegoat]

Use the base running airflow table that I sent. Yours is too low now.

[Lakegoat]

Are you planning on running E85? If not, make the stoich table 28.40000 across

[Lakegoat]

Make your Dynamic Airflow Disable/Re enable 4000/3900

[Lakegoat]

Your running too lean---look at your stft chart. Are you reading a wideband---don't see one in channels

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I have a wideband but it's not being logged, I'm ordering the cables so that I'll be able to. But the wideband reads 14.7 to 15.2 while cruising and 11.9 wot.

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My wideband is being logged now and here is a current log and current tune that I'm running now. With this tune the car idles a little high, is hard to start without pressing the gas, but the surge and hesistation are gone. When I use the settings that lakegoat recommends, the car starts quickly and idles perfectly, but stalls out on when returning to idle while driving. Overall the car is driving better than before.log7_16.hpltune 6.hpt