off topic, why are the piston pockets on the left piston so much different than the other piston?

it also looks like the machining is different on the left piston, relative to each pocket, intake side i am guessing.

both pistons have scorched on the thin area of the intake piston pockets.

what attention was given to those area's prior to assembly?

what rings were used?

what break in oil & method?

are either of the other pistons showing any signs of hard life?

was the same cylinder head used?

I also see tough life for my plugs on cylinder 1. I also run an aem series 1 ecu.

 

I just want to make sure that you know, all injectors have 12v sitting there, its the ecu that signals (grounds out in the ecu itself) that completes the circuit to fire the solenoid itself in the injector. The only reason I know this is I have kind of the same issue, power sitting at all injectors #2 does give fuel, sent them in to see if they be good, if they are I'm getting a new ecu.
Hope this helps

 

I just want to add that I am switching back to the stock ecu as well. Once I do that, I will send the Aem in to have it checked. There have been instances where people had issues with the Aem box and Aem verified it when it was checked out. I dont think it is very common but has happened. At this point I am just trying to change whatever I can as well as look into the fuel system to make sure everything is working properly.

 

Good eye! The reason the valve reliefs look different on the piston to the left is I had them flycut due to some very minor valve to piston contact. After the first melt down I thought cutting the pistons may have caused a thin spot so I used an Evo IX head gasket on the second build to achieve the additional valve to piston clearance I needed.

I used the Total Seal rings that come with the Manley pistons filed to fit, first build we had them gapped wider, the second build I tightened them up.

To break it in I used AMSOIL BreakIn oil and put a minimum of 500 miles on the motor at varying speeds and boost levels not high boost or full pulls just enough to put varying pressures on the pistons.

All pistons look good except the obvious failures, no speckles nothing of concern can be seen.

The same cylinder head was used on both builds, same cams as well.

 

I understand how the signal is sent however I'm not sure how to test it any ideas?

 

Anymore ideas I don't want this to happen again. What else would cause this cylinder to go lean and/or detonate?

 

I know how to make sure, but it requires disconnecting the injector you want to check. stick one lead into the power pin and the other into the signal pin and when the ecu sends the signal, you will read 12vdc at the connector, and its going to be cycling fast. and to make sure that you have continuity on the lead in the signal to MAKE SURE that your ecu is not sending it, you can disco the ecu and meter from the ecu connector to the injector clip on the signal wire, if its good and then you install the ecu and get nothing then its the ecu. hopefully that makes sense, kinda hard to explain lol

 

This is probably not the most popular opinion but I honestly think it's in the tune. Piston melting is detonation. This could be lean afr or overly advanced timing or some combination thereof. The problem is not the tuner or engine, it's the tuning method. When you really start to modify stuff one of the big things you alter is the flow variance between the cylinders, this is a good argument for not messing with the intake manifold UNLESS you can tune for it. You have the ability to tune individual cylinder trims, you just need a way to log information specific to each one to see where and how the variance occurs. The common method has always been egt logging and more now individual widebands. AEM sells an entire setup for this now and I highly suggest you look into this if you want to truly avoid repeating this. logging sensors is knowledge, knowledge is power, both metaphorically and literally in this case.

 

From looking at the log files i would also say detonation. If you look at the any of log files on Logs3.zip and take a look at the Knock Volts they are in the 1.8-2.0 range which is great and than after 7000 rpm it jumps up to 3.55+ and stays in that area till you lift. So there is the reason for the blown motors, now it boils down to tuners using too much timing for the ethanol content being used because your afr are in a decent range (if using e85) in the 11.8-12.0 range. Or something is messing up the injectors at the higher rpms but you would think something would show up or happen when your at your peak boost at around 5500 rpm when your motor is at its peak load if it is injector issues?

PS one more thing i also noted was right at 7200 your voltage drops from 13.2ish range to low 11's like 11.19 and 11.31 so maybe that's something to consider looking into. That will take a hit to how much your injectors are spraying especially if the injector battery offset is setup wrong.

 

It is obvious after looking at the Log, you need a new TUNER. He should of aborted the pull if he knew what he was doing.

 

How can I tell if the knock sensor is actually picking up knock or if it is just picking up motor noise?
Also here are a couple of pictures of the bottom of the head, notice the cylinder that melted is more silver and the others are darker.

 

looks like failure from being rich on that cylinder

 

On your log clift03.017.stf @ 6746 you motor start knocking all over the place.3.3v and up from there. Your afr also gets to 13.10.

So from like 6200rpm to readline you are to lean.

You other log clift03.014.dtf it is knocking all over the place and lean AFR's.

 

For me looking at the logs you are running to much timing, and way to lean for that much timing. Even your knock test log is lean and to much timing.

7547rpm 17.4psi, 13.38afr, 18.86* == to lean, and to much timing.

 

Logs 14 and 17 were a couple of the first pulls, if I remember right the EMS and the AFR gauge were not reading the same. The other pulls were after this lean condition, do you think it caused the majority of the damage without showing signs of it then finally let loose many pulls later? I still need to open the logs on my laptop to go through them but I would assume the later logs show better conditions AFR wise anyways.