2011 Escalade L94 Twin Turbo High Load Misfire - P0300

[asquinton]

Guys,

Any suggestions would be appreciated. I'm working a 2011 Escalade with twin turbos installed at about 9 psi boost. The engine is stone stock otherwise with the DOD locked out but the hardware still in the engine. The cam phaser is still active. This thing has been a total PITA compared to other builds I've done. I've had a misfire issue from the beginning. Wires have been an issue so I finally threw the kitchen sink at it with Moroso Ultra 40 wires, ceramic boots, fire sleeve and fiberglass wrap on problem wires. The wires seem ok now, (TF).

I'm still getting random misfire at 7 psi boost and up. As soon as I'm off the throttle, it comes back, runs fine and the CEL goes away after coming on during misfire. The plugs are AC Delco double platinum 1 step colder plugs gapped at .026" (factory is iridium). List of changes include:
1. 2.5 bar MAP
2 Turbo exhaust manifolds
3 Plugs and wires listed above
4. Intercooler
5. 2 Factory air filters
6. 2 T3 T04E turbos
7. Cast down pipes into factory cats and exh

I'm about ready to go one step colder iridium plugs gapped at .022" to see if there is something there. The only other thing I can think of is exhaust back pressure. The front cats are in, active and have no face melting. The tuning has been straight forward minus the misfire.

Any known solutions or ideas would be appreciated.

Thanks,

Aaron

[CptFalcon]

Need to post the tune and log. Sounds alot like spark blowout to me.

[asquinton]

I'm thinking spark blow out or burst knock. I've taken the burst knock out but not tested yet. I'll grab my other computer and post it. Thanks for your response.

The weird part on spark blow out is I run my GTO at 10 PSI (procharger) without any issues with the same plugs.

[asquinton]

Here's the calibration. My log files are too big to upload and I've not sorted clipping it shorter. When I get the oil leak fixed and take another log file and post it. Thanks for your help.

[CptFalcon]

Maybe try a colder copper plug like an NGK, also maybe another set of coils just to be sure they aren't dropping out at high dwell. You should tune your vve as well, were you planning on staying maf only? A log file would be more helpful.

[blindsquirrel]

"2.5 bar MAP" with the linear/offset from the LSA 3 bar MAP?

[edcmat-l1]

Need to get those junk plugs out of it. BR7EF is the plug you want.

[blindsquirrel]

Would you put a tiny little T3 turbine on a 210-220HP 3.1L engine?

[abc]

"Spark blowout" seems very unlikely to me at that power level. An easy test would be to tighten the gap to .020" and run a test or change the plugs out to a standard plug first with a gap from .020 to .024" as a test.
Although that may actually mask the real problem of some other weak leak in the secondary ignition system.

[Alvin]

Guys,

Any suggestions would be appreciated. I'm working a 2011 Escalade with twin turbos installed at about 9 psi boost. The engine is stone stock otherwise with the DOD locked out but the hardware still in the engine. The cam phaser is still active. This thing has been a total PITA compared to other builds I've done. I've had a misfire issue from the beginning. Wires have been an issue so I finally threw the kitchen sink at it with Moroso Ultra 40 wires, ceramic boots, fire sleeve and fiberglass wrap on problem wires. The wires seem ok now, (TF).

I'm still getting random misfire at 7 psi boost and up. As soon as I'm off the throttle, it comes back, runs fine and the CEL goes away after coming on during misfire. The plugs are AC Delco double platinum 1 step colder plugs gapped at .026" (factory is iridium). List of changes include:
1. 2.5 bar MAP
2 Turbo exhaust manifolds
3 Plugs and wires listed above
4. Intercooler
5. 2 Factory air filters
6. 2 T3 T04E turbos
7. Cast down pipes into factory cats and exh

I'm about ready to go one step colder iridium plugs gapped at .022" to see if there is something there. The only other thing I can think of is exhaust back pressure. The front cats are in, active and have no face melting. The tuning has been straight forward minus the misfire.

Any known solutions or ideas would be appreciated.

Thanks,

Aaron

Is this a real miss or is the misfire diagnostics just telling you you have a miss?

A log would be helpful

[asquinton]

"2.5 bar MAP" with the linear/offset from the LSA 3 bar MAP?

Correct

[asquinton]

"Spark blowout" seems very unlikely to me at that power level. An easy test would be to tighten the gap to .020" and run a test or change the plugs out to a standard plug first with a gap from .020 to .024" as a test.
Although that may actually mask the real problem of some other weak leak in the secondary ignition system.

I agree, however two of the plugs require exhaust manifold and turbo removal to change. :-(

[asquinton]

Is this a real miss or is the misfire diagnostics just telling you you have a miss?

A log would be helpful

real misfire for sure, it falls on it's face

[asquinton]

It looks like I found it. I turned off burst knock and bam, it pulls to 5500 rpm and zero spark knock. Time to shift it at 6000 rpm and start feeding it a little timing. More to come.

[verlon]

Try this

MAF Only PwrEn On DoD Disabled B2S1 02 off High Octane 2 bar run16 3-Nov-24 tune MaxBoost80kPa.hpt

[abc]

real misfire for sure, it falls on it's face

A few or even many miss fires don't usually act that way. Dropping a cyl. or two on a moderately powered boosted engine won't feel like it's "falling on it's face". We would have known if you posted the .HPL. I'm guessing the .HPL would show it pulling a lot of timing?

[edcmat-l1]

A few or even many miss fires don't usually act that way. Dropping a cyl. or two on a moderately powered boosted engine won't feel like it's "falling on it's face". We would have known if you posted the .HPL. I'm guessing the .HPL would show it pulling a lot of timing?

This is why a data log is MUCH better than a verbal explanation. I tell my customers "Don't tell me what's it's doing, show me". Most of the time the verbal explanation is wrong, as in this case.

A misfire under boost, especially due to spark blow out, is usually accompanied by some exhaust popping similar to back firing.

[gtstorey]

"2.5 bar MAP" with the linear/offset from the LSA 3 bar MAP?

Correct

Why?

[abc]

I was a little curious so I had to look and... Those spark tables are are the cause of it falling on it's face. Interesting to say the least. Even with the base corrections it seems off to me.
I'm gonna guess a .HPL will also show the MAP is out of whack also due to incorrect specs.?

[asquinton]

Try this

MAF Only PwrEn On DoD Disabled B2S1 02 off High Octane 2 bar run16 3-Nov-24 tune MaxBoost80kPa.hpt

Thanks!