Procharged 2006 LS2 GTO Fueling Problem - Must Max out VE to idle

[SB2PRO]

Help is greatly appreciated. I am working on a Procharged 2006 Pontiac GTO with an LS2 that I am unable to tune. The car was running fine until the owner rebuilt the engine and installed a cam. Now the only way it will idle is to almost max out the VE table values at an idle. The wideband shows it lean and it appears to want more fuel. It won?t rev and the wideband will go lean when you do. VE is maxed out in that region. The engine has good vacuum and I have sprayed it down looking for a vacuum leak. I have checked the cam timing and it is fine. The rail pressure is steady at 58 psi when running. I have tried 2 sets of injectors. The voltage to the injectors is good. I have checked the grounds and they are connected (back and front of engine). All of the sensor ranges seem normal. TPS, MAP, IAT, ECT, etc. There are no codes set. I am out of ideas at this point. This was a running tune prior to this, so I am suspecting something electrical/mechanical? Any suggestions, or ideas on what could cause this would be greatly appreciated.

[5FDP]

Tunes and logs may be helpful.

Is the wideband sensor in good condition?

What cam and did the displacement change at all?

[SB2PRO]

Tunes and logs may be helpful.

Is the wideband sensor in good condition?

What cam and did the displacement change at all?

The displacement has not changed, and is stock. The heads are stock. The cam is around .600 lift and 230's duration. I believe the wideband is good. No issues with other vehicles. It won't idle with the original tune/VE. The WB is showing 18+. If I substantially raise the VE numbers almost to max, it is hard starting, but will idle around 14 AF. I am scratching my head with this one. The plugs do look really black when pulled. I may throw another set into it and see what it does. Any other thoughts? Thanks.

[Scaldeddog911]

add some timing into the cranking table

[SB2PRO]

add some timing into the cranking table

Thanks for the response. At this point, I'm not as concerned about the hard starting as I am the huge VE numbers required to make it idle. The numbers are maxed out and can't go any larger for it to rev. Fuel pressure is good and stays steady when idling and trying to rev. I know the injector data is good. I am going back to square one today and putting it back just like the last time it was known to have ran correctly. I'm not pulling out he cam though. It wasn't running when it was brought in after the owner freshened the engine, and put in a cam. LIke I said, I checked the cam timing and it was ok. The compression is 155 to 160, which I don't feel is out of line. Thanks again. All suggestions are appreciated.

[Scaldeddog911]

does it have a custom operating system?

[SB2PRO]

does it have a custom operating system?

I have tried it both ways. I believe it has more than one problem. It was the factory OS. And would not run. I converted it to a 2 bar SD because I felt that would be better. After having to crank the VE to make it idle and being unable to resolve, I switched back to the original tune. It acted the same way. However, I noticed yesterday that the MAF sensor was not working in that tune. When I switched back to the custom OS (Speed Density, MAF disabled), I forgot to put the 2 bar map sensor back in and it ran with lower VE. You could actually rev it. It was idling around 105KPA. I am going to investigate this today. The 2 bar map sensor would idle around 60 KPA, which seemed normal, but you have to crank the VE. I'm going to check the output of both sensors with my mityvac today and compare. This 2 bar operating system is weird. It has a separate boost VE table. At ideas?

[Ben Charles]

Sounds like wrong Map data and entering fuel in the incorrect spot

[SB2PRO]

Custom 2 bar operating system and 2 bar MAP sensor. The tune and the log file below are with the VE maxed to get it to idle. As you rev it, it goes lean? What am I missing. I am concerned about the MAF sensor interfering. I think I have it disabled correctly? It is weird that it runs better with the one bar map installed. It idles at 105 KPA with this tune and the 1 bar MAP and will rev. Any thoughts?

[SB2PRO]

Sounds like wrong Map data and entering fuel in the incorrect spot

I thought the same thing, the MAP seems to be logging correctly with the 2 bar. I have attached the tune and log file. Let me know what you think. Thanks.

[SB2PRO]

I finally got this thing resolved. Thanks to those who replied. Evidently, the MAF sensor not working was creating a problem even if it was shut off in the tune. Originally, I had the High fail set at 10 and the Low fail to 0. Once I saw the MAF was not working, I set both to zero. Still no luck. I finally went back to the original 1 bar tune with the MAF disabled. Once again no luck, so I decided to try to get the MAF sensor working. After checking the wiring, I swapped in a new MAF sensor. After turning it back on, the car ran normal. I swapped the 2 bar OS and MAP sensor back in and all was good. I am still thinking I had the MAF sensor disabled correctly and that it must be a quirk of this OS or ECU?