Please help diagnose P1516 after WOT

[tirefryin_s10]

Hey guys I was recently playing with a LS3 engine/GMPP E67 controller with a procharger on the dyno and we ran into some issues with code P1516 popping up in high rpm dyno pulls. I can not verify if the code is popping up before or after I lift at the end of the run but right after I lift and get the car slowed down it is in reduced engine power mode and p1516 is there.

We did verify the throttle body was not obstructed or sticking in any way we also changed the throttle body out for a brand new unit with no change.

The blow off valve on this particular set up is somewhat far away from the throttle body but not anything too crazy its just on the supercharger side of the intercooler.

This set up is pegging the mas air flow sensor but fueling still held really nice on the wideband and did not appear to be a major problem, the throttle appears to work just fine in all normal driving and idle conditions but under wot it always screws up. The injector flow rate and stoich values have been scaled for larger injectors.

Any and all help is greatly appreciated.

Here is a log and a tune file:

FINAL FOR NOW WITH P1516.hpt
wot 4.hpl

[CRTD]

That tune won't open on the home pc. But I would bet the P1516 diagnostic table higher rpm cyl air values need to be increased to probably 1.6-1.7 and that should go away. Just look at your log and compare the rpm vs cyl air to what's in the diagnostic table. Adjust as needed without going too far.

[tirefryin_s10]

which P1516 table are you referring to? I have not been able to find one in this OS.

[schpenxel]

He's probably thinking about P0068 table in engine diag, airflow.

Set enable RPM for P0068 airflow correlation to max to disable it. Low chance of it affecting 1516 but it's worth a shot

[tirefryin_s10]

Already tried that to no end.... Any other suggestions or ideas?

[ecotec88fiero]

Which way does the throttle open? Could you have a throttle plate being forced in the wrong direction by the high airflow?

Or after you let off and the boost spike before the BOV opens is moving the throttle in a way that isn't commanded?

P1516 is a mismatch between indicated and predicted throttle angle so if the throttle is over or undershooting its predicted target due to high airflow moving it or a boost spike holding it or slowing it down you could have an issue.

You ruled out wiring to the throttle right?

[mowton]

^^^^^^^ Agree It is most likely a correlation error between the PCM throttle control and TAC module. How many pounds of boost.
?

Does the TB have a gold or silver blade? sb gold

Log the ETC/TPS PIDS (volts and %)

Ed M

[tirefryin_s10]

13-14 psi and it was a gold blade so was the one we replaced it with. I agree it is likely a correlation issue between the tac and the PCM but just not sure how to get around it.

Not sure which direction it opened. I don't have the car with me right now either. TPS shows 88% until the end of a WOT pull ...

Thanks for everyone looking into this with me.

[tirefryin_s10]

Anyone else help with this? I was considering doing a write entire to swap it to a different OS and see if that would change anything.

[veee8]

You can contact [email protected] with your file. They can provide you with a beta that has the po1516 diag table in there. Then just raise it up a little until the problem goes away. Tag engineer with PO1516 test in the email.

[Montecarlodrag]

Doing a write entire will not change anything since it does not write the TAC portion of the OS.