LS1 Trans Am leaning out above 4000 rpm

[Gripenfelter]

Heads and cam car. This year I changed the heads, went to LS3 injectors, FAST 102 intake, 102 TB, etc.

At first I thought it was the MAF but apparently it's not. No matter how much fuel I add to the VE tables it still goes lean above 4000 rpm even with the MAF unplugged.

Fuel psi is perfect and never drops. I have new pump and I changed the fuel filter at the beginning of the season anyways.

Injectors were flow tested and showed 42#s which is what they should be for LS3 injectors.

What am I missing here?

At 4800 RPM and 40KPa, my cylinder air mass is 0.30 g/cyl on the log, but the VE table is commanding on the order of 0.8. Attaching log and tune file with MAF unplugged.

July 12_2.hpl

July 12_1.hpt

[TCSS07]

couple issues i see with the log - why is the tps reading only 24%? the throttle doesnt seem to open which is why the map is only reading 44kpa and the cylinder airmass being low which is why your commanding such a high ign timing 30+ degrees as a result of the throttle %
is your throttle drive by wire or cable driven?
also under torque management under maximum torque you have rpm vs gear maxed but vs rpm is set to 0 - max that out also

[Jay@HAP]

why is your TPS only going to 25%?

Sorry I just that was posted when I refreshed the screen.

TPS voltage is maxing out at 1.50 volts or so.

[Gripenfelter]

I wasn't WOT. Just part throttle. Just doing part throttle testing for now which is why the TPS is only 25%.

I'm cable driven.

So I should put the vs. RPM at 868 as well?

[5FDP]

Id' be looking at vacuum leaks if it's always lean.

[Gripenfelter]

Id' be looking at vacuum leaks if it's always lean.

I don't think it's a vacuum leak. I have a vacuum/boost gauge on the car. Goes lean above 4000 rpm mostly.

[5FDP]

You won't know that unless you test for a vacuum leak.

Looking at that log it shows me it's lean all over. Your wideband even at normal driving is way above 1.00 lambda, upwards or 1.05-1.15 most of the time. Unless you VE is just that far off everywhere else.

[Gripenfelter]

You won't know that unless you test for a vacuum leak.

Looking at that log it shows me it's lean all over. Your wideband even at normal driving is way above 1.00 lambda, upwards or 1.05-1.15 most of the time. Unless you VE is just that far off everywhere else.

I'll take another look this weekend thanks.

[TCSS07]

smoke test to verify for any leaks, fix if any are found - if none are found add like 10-15% to your ve chart
another test you can do is in closed loop - idle and see how the trims are if there lean which looking at the lambda reading they probably will be - if you raise the idle rpm the and the trims even out then you most likely have a vacuum leak if not then the fueling is off and needs to be adjusted better

[Gripenfelter]

smoke test to verify for any leaks, fix if any are found - if none are found add like 10-15% to your ve chart
another test you can do is in closed loop - idle and see how the trims are if there lean which looking at the lambda reading they probably will be - if you raise the idle rpm the and the trims even out then you moat likely have a vacuum leak if not then the fueling is off and needs to be adjusted better

K I'll do that right away and post back.

Thanks.

[Gripenfelter]

Midas checked the car today. No vacuum leaks. They said even when they loosened one hose, the car would start surging and it's very obvious...so no leaks.

[5FDP]

Calibrate your wideband if possible too.

Are we safe assume the wideband is placed before the cats if you are running them?

[TCSS07]

like 5fdp said - make sure the wideband is functioning properly and set to the proper calibration setting and when all is right as rain youll just have to make the necessary fueling adjustments for idle,p/t and wot

[Gripenfelter]

Ok. Actually, I'm going to borrow a buddy's wideband next week and use it instead as a sanity check.

The wideband is right after the header but yeah, it could be off.

[Gripenfelter]

Wideband was fine.

No vacuum leaks.

Rechecked the injectors. Despite the shop and the seller telling me they were 42# LS3 injectors, they were not. I should have double checked myself and not taken their word for it.

They were FAST 39# injectors.

Installing proper Fuel Injector Connection balanced and flowed 42# LS3 AC Delco injectors tomorrow.

[lukearmstrong1990]

is your fuel system dead head or it has a return style system with out of tank regulator?