New LS3 Inj Fuel Trims Now Maxed

[Exidous]

I had some smaller racetronic injectors and swapped to LS3 injectors. I have verified fuel pressure (58psi) at the rail, injector polarity (if it matters) and that the injectors are firing (pulled rail and placed towel under all the injectors).

The issue is that the LTFT's are maxing with the VE at what I had with the racetronics. If I add 50% to the VE I get close to 0% trims. There is no way Idle requires 96% in the VE. I am also using a 1bar SD custom OS. The 1bar Custom was running fine with the racetronics. I have also verified AFR with the NB and WB.

I used the data posted in another thread/ls1tuningguide.com and checked it against a couple other sources. I also verified the P/N of the injectors to confirm LS3 42lb.

Could you folks please take a look at my tune and see if I am missing something glaring.

Thanks,

Patrick

[Exidous]

48hr bump :-) I'll take any ideas.

[Pekka_Perkeles]

So you want to run SD, i.e. no MAF?

If so, change the P0101-P0103 to "0 - MIL on first error". This would allow the engine run properly at SD with your Speed Density Custom OS.

This is definitely needed in 2 & 3 bar Gen III systems, but feel free to search here if it applies also with 1 bar SD COS.

[Exidous]

I'm already running SD. I was running it with the old injectors just fine. The MAF isn't even connected and I have no MIL.

[Exidous]

I should note that it starts fine but as soon as afterstart is done and OL kicks it runs like crap. Once CL starts and the LTFT's max out it's okay again during idle only. I cannot hit the throttle.

[Exidous]

Bump


Pretty please?

I tried the injectors in a buddies '10 Camaro and it ran fine.

[Pekka_Perkeles]

If the injectors are fine and if the injector data is right, then isn't it obvious. There is something wrong in the tune.

Again, make sure that the PCM is properly in SD mode. Set P0101-0103 as I suggested and then try again.

[Exidous]

It's a Custom SD OS. The MAF isn't even installed and the the MIL codes are set. Something with the injectors has to be the issue. IE the data. With the racetronics, all fueling tables fell into the range that one would expect for the setup. 45-50 at idle in VE and 100ish at WOT. With these new injectors it now wants at least 50% more in the VE table. There HAS to be something in the injector data that I am missing.

The only other possibility is the injector polarity. I have verified that the harness is wired for common + between them. Does the LS3 use a common ground instead?

I'll check on the MIL one last time but I haven't changed them since before the injector swap and it wasn't an issue then.

[Pekka_Perkeles]

Interesting. It seems that your injector data is correct.

Now this again: "I'll check on the MIL one last time but I haven't changed them since before the injector swap and it wasn't an issue then."

I understand that it's weird that now there's a problem when you have swapped the injectors. But I've seen strange situations before when MAF hasn't been failed properly (as I earlier explained). Just make sure it is like this:

[Exidous]

I've got the transmission out for a rebuild. I'll be back!