Working on a small issue now. Truck was running great and then started misfiring under light acceleration. Made it home slowly and was logging the whole time with no codes.

Let it sit over night and went to start the next morning (no luck) and it pulled a code for P0336 or Crankshaft Position Sensor.

Pulled the sensor and it looks okay. The flywheel isn't hitting it and the sensor probably has 175k miles on it or so. Just transferred from build to build.

I have a new one on they way and hopefully that's all it is. We'll know soon!

Also have a Moser 9" on order. After that, we'll be about ready to run.

 

Sensor was fine.... pulling engine. Oil and Filter full of copper. Fun way to start off a freshly built 408 but it happens.

 

Wow. How many miles on it?

 

Bet it took out the thrust bearing.

 

I'll find out tomorrow. Engine is ready to pull now.

Maybe 200 miles on this engine. Never saw high / excessive boost while breaking in. Made a few pulls after 50 miles up to 6,200 rpm at less than 5 psi. Conservative timing.

I'm running an auto meter oil pressure gauge in pressure port on top of motor. Was idling at 20 psi, never knocked (in scanner or audible). Had scanner hooked up entire time.

Timing started bouncing, o2 voltage fell off, went lean when misfiring at 1300 rpm.

Idled good when I killed it to start troubleshooting (that's the strange part to me).

Turns over good by hand still so we'll see how bad it is.

 

Video of reluctor wheel through Crankshaft Position Sensor...

 

Time for a billet wheel! I'm having the same issue on my 408. Mine misfires around 3k rpm. Rebuilt the motor put it back in same issue. Motor is currently out of the truck waiting to have the billet 24x wheel put on. Got it from late model engines (LME) for 200 bucks. Hopefully that fixes the problem. It's the only thing i haven't changed...besides swapping from the original 58x to 24x

 

Yep...bad thing is when I had Scoggin Dicky build it, told them it was going to be a higher HP turbo build and anything it needed I would pay for. Even bought the msd two step from them when I dropped the block off for machine work. They knew it was going to be abused haha...wish I could of made a pass or at least got a good run in. Glad I caught it before anything else happened.

The bottom end is suppose to have a Callies crank and rods. I’ve heard of the horror stories on the callies crank and reluctor wheels.

Pulling it now. Will have pics up soon of the damages.

 

Well ****. Mine is also a callies crank. Hopefully the damage is minimal.

 

any update?