Had an anomaly today. I have about 1500 km on the engine since I put it in. So I'm still breaking it in but all seems well so far.

Got re tuned by the tuner...safe conservative tune and on 94 octane.

10.5 to 11.2 AFR @ WOT. I'm not sure what the timing is at though.

4 psi boost. 76mm on a forged 370 built for over 800hp. Compression is 10.8:1

LS9 GASKETS AND ARP HEAD BOLTS.



Wot pull today I got a CEL random misfire.

And then about an hour after on another WOT pull I got another CEL for cylinder 7 misfire.



Oil pressure is about 200kpa which I believe is around 30 psi. At idle.


I swapped injector 7 with injector 1. And swapped spark plugs too.

Just to see if that's the issue.

I don't really wanna blow this thing up.


I'm also spraying a small amount of untuned 50/50 meth water mix.can't spray just water cause it'll freeze with the temps we have out here.



Coolant looks good.

No signs of oil or coolant around the head.




What gives? Anything else I should check?

 

You really need to know the timing in it...

How did the plug look? Insulation cracked? Any speckles on the inside? Inspect the plug wire.

 

The plug on #7 had more black carbon inside it than #6.

Know what I mean?

And it wasn't uniform carbon buildup. One side of the plug had noticeably more carbon on it.

I made sure the plug wires were pushed on all the way etc.



This has me a little concerned as that's the CEL I got when I blew a hole through #7 piston on my 5.3.

But the truck isn't billowing out white smoke and I still have oil pressure.

And the plug was saturated in oil when I blew the piston last time.

Again this happened at WOT this time.

 

I mean make sure the plug wires arent burned or touch the exhaust anywhere. Still need to know how much timing you have in it...ask your tuner.

 

Try swaping coils? Sounds like could be a dead coil or dieing coil

 

If I get a CEL today I'm gonna swap coils after. That's IF I do a WOT run. And I'll log it and check my timing too.

Oil pressure seems good this morning. Drives fine.

 

If your timing is right, I would replace the coil and wires. It's a minor cost compared to replacing the engine once more.

 

I did a little WOT run today from a roll. Only stretched out a gear. Probably second.

And timing fluctuated between 12-13-14 degrees.

I will check again tomorrow but how's that sound?

Afr is about 11:1

 

CEL didn't come on this time.


?

 

I'd say 14 or 15 degrees timing @ 10.5 AFR is how she's going at WOT.

94 octane and a bit of 50/50 meth n water.