2 step possible blown motor 😡

[bstuder11]

Oops

[joecar]

what was wideband lambda, commanded fuel EQR, and spark advance...?

[joecar]

Sounds like the upper ringland ruptured on a few pistons.

[joecar]

The 2 step should not be cutting fuel.

[joecar]

Post your tune file snd log files.

[bstuder11]

Post your tune file snd log files.

Maybe tomorrow, I should be asleep right now lol.

[Tre-Cool]

a proper 2 step actually cuts timing not fuel.

I would never use a fuel cut to build boost, especially on a turbo motor.

you would be better off with the msd or lingenfelter 2 steps, you can't use the factory ecu to build boost.

[GMPX]

All that function is doing in the PCM is using the factory rev limiter at a lower setting as set by the user (which for LS1 was either Fuel cut or Throttle limiting), but it was more of a Valet mode thing, not a true two-step limiter.
Hopefully whatever has happened isn't too bad.

From the LS1 COS Tutorial:
CAUTION
The Valet mode RPM limiting uses fuel cut-off to limit the engine RPM, it does not use spark cut. It is not recommended you hold the engine on the RPM fuel cut for very long as the engine can run lean and damage the engine itself and/or catalytic converters, use it sensibly.

http://download.efilive.com/Tutorials/PDF/Custom%20OS%20Upgrade%20Tutorial.pdf
(http://download.efilive.com/Tutorials/PDF/Custom%20OS%20Upgrade%20Tutorial.pdf)

[bstuder11]

All that function is doing in the PCM is using the factory rev limiter at a lower setting as set by the user (which for LS1 was either Fuel cut or Throttle limiting), but it was more of a Valet mode thing, not a true two-step limiter.
Hopefully whatever has happened isn't too bad.

From the LS1 COS Tutorial:
CAUTION
The Valet mode RPM limiting uses fuel cut-off to limit the engine RPM, it does not use spark cut. It is not recommended you hold the engine on the RPM fuel cut for very long as the engine can run lean and damage the engine itself and/or catalytic converters, use it sensibly.

http://download.efilive.com/Tutorials/PDF/Custom%20OS%20Upgrade%20Tutorial.pdf
(http://download.efilive.com/Tutorials/PDF/Custom%20OS%20Upgrade%20Tutorial.pdf)

THANK YOU SOOOOO MUCH!!! it doesn't tell me what I did to the engine yet but I must have dyslexia because I completely read that wrong and my friend that's been tuning around here for a couple decades told me it used spark also so I felt pretty sure that's what it did. He does not use the valet though he uses the msd I was gonna buy for 2stepping his truck and dpare on his Vette so he probably hasn't really ever paid much attention to it. so I used it for maybe 3 seconds and only had it dropping 10Rpm and my A/F was actually really rich at 8; it usually stays around 10:5 just standing on the brake and it starts right up still and idles nice and smooth so im thinking maybe its just a seal I blew in the turbo allowing oil to get into the exhaust that way... any thoughts on that?

[Tre-Cool]

I think it might be coincidence if there is anything wrong with your motor.

Generally if your cuting fuel for a long time your not really going to be burning anything, so heat & unburnt fuel isn't going to help spool up the turbo.

What you want is low/retarded timing & excess fuel.

[joecar]

He deleted the text from his first post, and he deleted his other posts (which I can see)...

his first post said that afterwards engine would sometimes blow blue smoke from exhaust on throttle.

[hrodgmc]

Tuning for a couple decades means the tuner is about one of 6 or so tuners that were on the gm tuning bb.