Motor blew up today.....need some tuning experts in here.

**EagleMark** · 10-11-2013

I agree. I think your valve spring was broke causing this issue long before everything came flying apart.

Log pictures clearly show it was not a transition issue.

**lwrs10** · 10-11-2013

Originally Posted by mecanicman

The valve spring explains your map signal. Have pic of the engine bay before you took it apart? Still like to see that log.

still trying to wrap my head around what you are getting at with the map signal. It went all the way back to october of last year through my logs when my engine was completely stock. The MAP looks EXACTLY like it does now. And it ran great then. Same tiny little dips WOT, same max KPA, etc. And the only thing common between the current motor was the shortblock. Let me post some pics....

**Caleditor** · 10-11-2013

Originally Posted by lwrs10

still trying to wrap my head around what you are getting at with the map signal. It went all the way back to october of last year through my logs when my engine was completely stock. The MAP looks EXACTLY like it does now. And it ran great then. Same tiny little dips WOT, same max KPA, etc. And the only thing common between the current motor was the shortblock. Let me post some pics....

And you could see that the AFT1 flag had just run

**lwrs10** · 10-11-2013

Originally Posted by Caleditor

And you could see that the AFT1 flag had just run

there is that too.

we can throw out the WOT stuff, because I had a mechanical failure. But....gotta get rid of this lean then rich spike at part throttle once i fire up the new engine this weekend.

and dammit....I do not have any pics of it. I have half completed pics.

**mecanicman** · 10-11-2013

Broken valve springs cause cylinder missfires which can show up on wideband as lean. You may still have another problem, I would still like to see the log you referanced above. Just checked out your build thread on s10 forum. I have 3 s10s, here is the link to my turbo project if your interested. http://www.s10forum.com/forum/f213/j...i-hope-503806/

**lwrs10** · 10-11-2013

Not sure a broken valve spring would make both banks go lean at the same time though.

**mecanicman** · 10-11-2013

What injectors are you running?

And both banks is a valid point that there is another issue at work. Now if only I could see this issue..................lol

**lwrs10** · 10-11-2013

Originally Posted by mecanicman

What injectors are you running?

And both banks is a valid point that there is another issue at work. Now if only I could see this issue..................lol

Which log would you like to see exactly?

And I am running the LS3 injectors.

**mecanicman** · 10-11-2013

I want to see a log with a good capture of your lean/rich spike. And your injector data is way wrong, which may be contributing to the spike. Unfortunately I'm back to work today, but I'll get you the data in the correct format tonight.

**lwrs10** · 10-11-2013

Injector data is wrong? Fuel pressure is 58 psi, and the flow rate is 41.7lb/hr at that pressure.

The offsets are derived from the stock LS3 tune, using the 400 column, which is equal to the 0 kpa line in our tune. The IFR and offsets are flat across because I am using a return style system.

The short pulse adder is also straight out of the LS3 tune, but interpolated for the 0411 values, as are short pulse limit and minimum pulse width.

But I am interested to see what you have. I find it very hard to believe stock GM data for a stock GM injector is wrong.

**mecanicman** · 10-12-2013

If you have all the answers why are you asking for help? I dont need to keep arguing with you. I can promise that using ls3 injector data does not result in negative short pulse adder values like you have, or a table the looks anything like that. Good luck with your tune.

**lwrs10** · 10-12-2013

Originally Posted by mecanicman

If you have all the answers why are you asking for help? I dont need to keep arguing with you. I can promise that using ls3 injector data does not result in negative short pulse adder values like you have, or a table the looks anything like that. Good luck with your tune.

I am in no way trying to argue. I can post a stock ls3 tune that has those negative short pulse adders. And as I said before, I would like to see the data you have.

My apologies for making you mad...totally not my intention.

**EagleMark** · 10-12-2013

Listen guys, there's never been arguing here! Maybe difference of opinions/knowledge or facts? But we just talk about it and come to a conclusion!

mecanicman has been asking for data logs and none posted yet? He seems more then willing to help and has some knowledge I'd like to hear as well! Maybe if he had them this difference could have been answered already?

Maybe it's my fault as your first post said

*will attach some files when I figure out how*

So when you click Reply to post, look underneath and click Go Advanced, then under that box is the attatchement manager and you can upload your files. I'm not sure all HP Tuners file extensions have been added so if you have a problem let me know what the extensions are and I will add them. For now you could just zip the files.

**lwrs10** · 10-12-2013

I will post some logs in a few minutes. I stayed up all night swapping in the other motor I had and drove it to work today. No way for me to post logs from work, as I do most of my posting from my phone. That should explain the delay in those logs.

BTW, it did the same exact thing with this "new" motor. I looked through the tune to see if I missed anything when I changed most things back to stock. Found I missed the injector timing, and the new motor has a stock cam. Set the EOIT to match what I had in there, which was to start when the exhaust valve closed. That lean spike went away completly until I made an idle airflow change and it came back. Then I set the EOIT back to the stock numbers and viola! No more massive lean spike.

Once I get my heads back together and swap the valvetrain over to the new motor, I have a damn good lead on how to fix it!

**lwrs10** · 10-12-2013

here is a log with some pretty distinct spikes. One happens about frame 3850.

https://docs.google.com/file/d/0B4qs...it?usp=sharing

Here is a 2010 Camaro SS LS3 bone stock injector data screenshot. This is exactly what my injectors came out of. These PCM's work off pressure delta, but to figure out what to use for an 0411 with a return style fuel system, you simply find your fuel pressure number in those numbers and use it. The pressure delta at 58 PSI rail pressure would simply be 58 for 0KPA. So pretty easy to do. I also have this data in E67 format too that uses the 400 scale.

Most of the short pulse adder table is negative because of the non linearity of these below 4ms pulse width. They actually have an upward swing from the linear flow line right below 4ms....hence the negative number to reduce fuel. Just below 1ms pulse width is where the flow falls off, and thats where the numbers go positive.

And here is the short pulse adder table side by side with mine. Surprisingly the 0411 has more resolution.