HydroStream6

iTrader: (16)

I recently did my own front mount turbo setup, coming from an STS setup. I'm wondering if the added heat under the hood now could be causing this or if it's somewhere in my tune.

Anyways, the car is tuned 3 bar SD open loop. No front O2s, OL all the time. After the car sits idling for about 10 minutes, the AFR goes from about 14.6 to about 19.0 and then progressively gets leaner until I shut her off. It climbs to 15:1 slowly then climbs faster after that. I've monitored the fuel pressure and it doesn't drift at all.

I wondered if my injectors were getting too hot and going funky due to underhood temps now being hotter with the turbo under the hood. I checked the injectors cold and they all ohm out at about 12.5ohm. Hot when the car does this lean out thing they ohm out about 1ohm higher, 13.5ohm. They're all very close to each other though.

I can post a log but I did it with my cable with no wideband O2 input so I'm not sure how useful it'd be. I'd have to get my buddys cable to get the wideband input.

Now that it's getting warmer out as well, if I sit at a light for a few minutes, the car will go into this "mode" (for lack of a better word). Any TPS above like 10% brings the AFR to where it should, but light throttle and idle start to go very lean (17-19:1). Then I shut it down, wait for it to cool down, and get moving down the road, then it's fine again. Going down the expressway even light throttle, this never happens.

Also going to include a FULL rundown of the car just for reference:

2004 GTO
Forged 370, 9:1
317 heads
Patriot Dual springs
LS6 cam
ARP studs
MLS gaskets
TC76 front mounted, 3" downpipe, .96 AR exhaust
46mm wastegate, 1.875" dump
FuelLab regulator 1:1
58psi base pressure
Mototron 60s
Twin Walbros
4L80e, Yank 3600
HPTuners, 3 Bar os
3 bar map sensor

Just a couple other random thoughts:

Car is in OL all the time because there's no front O2s so it automatically goes to OL. STFTs and LTFTs are inactive on the log.

Since my 4L80e swap last summer, the PCM has not known the vehicle MPH. Don't know if this could be related somehow. Did not have this problem last year with the CL/OL Maf tune though.

Also didn't have this problem with the new turbo setup 3 weeks ago with the MAF OL tune. Don't ask why/how but I did drive the car for a bit on the MAF with no front O2s. Part throttle at that time was close enough and WOT was fine because it's OL anyways.

Any ideas?

Here's a copy of the tune if you care to look. It's using HPTuners Beta though so you'll need beta to see it.

Current SD Tune

Thanks,
Adam

poconojoe

iTrader: (43)

I don't think the link works to download, is the file set to share?
You should be able to attach the file to your post, using the advanced feature and not have to store it on a third party site

BLK02WS6

iTrader: (2)

Don't know what HP Tuners 3 Bar has, but EFILive SD COS has tables for adding fuel based on IAT and ECT - if ECT isn't going up, you could possibly use IAT to add a little fuel in that area. Or, just command it a bit richer in the idle cells to cover you...

HydroStream6

iTrader: (16)

If you click on the link it will take you to the page where you can DL the tune.

HydroStream6

iTrader: (16)

Lean Log, no AFR though. Goes lean about 3/4 way through. You can see that the timing starts oscillating trying to control the idle.

poconojoe

iTrader: (43)

I could see the file name, but it wouldn't let me download it, like it wasn't set to share

HydroStream6

iTrader: (16)

I attached it to the original post now.

I picked up some O2 bungs so i'm going to put the front O2s in tonight and see how that goes with LTFTs disabled but STFT enabled.

poconojoe

iTrader: (43)

Make sure you mount them in the upper 180 degrees of the pipe, if you're putting them on a horizonal section

LSxPwrDZ

iTrader: (4)

Sound's like IAT getting heat soaked to me.