pcmhacking.net

Hey guys,

I've got a friend with a 2001 VU ute LS1. They purchased it some time back with an OTR intake and MAFless tune already installed.
They have been complaining it doesn't always idle very well and smells like its running rich. We cannot find anything else wrong other than it running rich - to the point of fouling plugs sometimes.
I have noticed it will never enter closed loop - or at least never has when I've had the scan tool on it. The O2 sensors are working but are pegged at 850mV when its idling.

I've got no prior experience tuning LS stuff, but since I have an OBDXpro I purchased some time ago with the intent to have a play around (but have never have) I thought I would try and read it with PCMhammer. I always assumed it would be tuner locked but to my surprise it wasn't and PCMhammer read an entire bin without issue.

The OS is 1290005 which from searching is a commercial EFI live OS so I wont post the bin here (unless someone can confirm there's no issue doing that).

I did find a 1290005 tunerpro XDF searching online. Looking at it with my untrained eye and reading online I've noticed a few things:

- The closed loop enable coolant temp vs IAT table + LTFT enable scaler are set to 140 degrees.
- The LTFT and STFT IDLE flags are both unset / disabled
- The open loop AFR table contains non-stoich values (lambda 1.04) below 100 degrees and 60kPa - which I'm assuming will also prevent closed loop.
- The values in the main VE table are all way higher than I expected - it would be cruising at about 150-160% VE. This doesn't make sense to me unless the injector flow rate or something is off.

Also noticed that the MAF High Freq Error is still set at 13500hz. My understanding was that this is normally set to 1 with a mafless tune so the MAF sensor fails instantly and forces it to use speed density? But I'm guessing this maybe not the case with the EFI live OS?
There is also a lot of DTC's that have been turned off - including P0300 which I guess explains why it never had a misfire code.

I'm unsure if I should try and fix this or start again with a factory OS?
Should I try and re-enable closed loop so it at least corrects itself at idle? It seems to drive alright otherwise (but is running rich).
As far as I'm aware it is completely standard other than the OTR intake and missing MAF sensor.

Thanks in advance

1290005 being a custom os will already have the maf disabled. no need to modify the maf fail points.

post the file i'll take a look at it.

Mod edit: Please do not post commercial software

BIN is attached

so injector flow rate is stock, the 1.04 lambda below 60kpa is effectivily keeping it out of closed loop, but it's also not enabled as you detected.

fuel map looks normal for a stock map. spark timing is probably a good 4 degrees to high, but you can see they have pulled a bunch of timing out through various points.

you can download efilive and be able to view all the maps, you dont require a cable.

Awesome mate thanks for your help.

I found a very helpful forum post here: https://forum.efilive.com/showthread.ph ... -with-LTFT
which was useful in explaining how the open loop / closed loop works in this OS

if you want to use HPT you can with this file.