Tune issues. occasionally dieing at stop.

[rfrankb4]

This tune is from a short drive while logging data for VE tuning. Tune idles well in P/N and most of the time while driving around. I have two apparent issues when coming to a stop while driving.
1) as exhibited in this file around frame number 3400 the engine died at a stoplight and I do not know why.

2) I have a recurring problem with the same effect that is apparently caused by the computer occasionally reading 2% throttle while the blade is closed. I have tried two different sensors and this is an intermittent problem. Most of the time the sensor reads correctly.

data follows:

This is a LQ4 in a 66 chevelle DBC, 2010 camaro intake, LS3 heads milled 0.025, 4l80e, Fuel pressure is 58psi, 227/232 ~.610lift 112+4 cam, base tune is from a 2006 express van, computer and harness were originally from a 2007 express van. I have Wideband and HPpro. This is a 2 bar OS with the MAF failed so that I could adjust the offset on the MAP sensor. STFT LTFT and DEFCO are turned off.

Injector data is possibly wrong. They were supposed to be LS3 injectors but that was obviously wrong and had me ending up with VEs well over 100 for most of the table and throwing lots of other calculations based on cyl air volumes out of wack. From a search of the part number i thought they were 33s and tried that but VE still looked too high so in this tune file I have them down as 31lb/hr. I will probably be getting changed to 42s so I have a known set in the future but this is not all of my problem.

This is my first attempt with HPtuners and while I have read tons on here and feel mostly comfortable with the system it is likely I am missing several key simple concepts so do not hesitate to ask me if I made what some would consider simple mistakes.


thank you for the help

[gn2beatu]

Before you make any more changes, you need to find what injectors they are for sure, and load the correct data. Otherwise you will be doing it all over again when you do get the right data. VE table hasnt been smoothed, but it isnt terrible like others I have seen either. After each round of adjustments, smooth once. I bet once you get the injectors data dialed in, your issues will go away after finishing up the VE table. You do have a few flat spots around the idle to 2800rpm range. I would just smooth the table once and then do a new log.

The computer and harness are from an 2007, tune from a 2006, isnt that the year they went from 24 to 58 crank reluctor? You didnt state what year engine you have, but since its running, Id assume an 06 or older.

[rfrankb4]

Thank you for the response. The engine is a 2007 but the Express vans had the 24 tooth set up. The vans had them one year longer than anyone else as I understand it.

The numbers on the injectors seem to correspond with 33lb/hr ls2 injectors. Should I just use those numbers even though they appear to give me VE values that are too high and could cause issues with other tables that use calculated air volume?

I have smoothed the VE table after adding the data from this morning to my newest tune that I will use on the way home.

[thebeewantsboost]

before i read that the injector data was possibly wrong, it already sounded like the problem.

[WS6FirebirdTA00]

Check your P/N on the injectors for a flow rate at a pressure.

Verify your system fuel pressure (is it fixed or varying).

Calculate (with the spreadsheet in the stickies) your new IFR values. You will also need to enter the proper offset tables, short pulse, default pulse, etc.

Fix that and delete some PIDs. Take logs that show these higher values. Looking at many spots in your tune the car is rich.

Get fueling right first, then idle. Your idle airflow is way off. It should not be that high when cold and should not be that low when hot.

[rfrankb4]

Alright, I have checked the part numbers again and they are reading as LS2 injectors. So I copied data from a 2006 GTO over into my tune.

I increased some of the operating temp idle air flows until I can get a P/N switch wired.

And I have started VE tuning the points I can easily hit while driving around town. I will post a tune up tomorrow after a little more VE tuning.

Thanks for the help.