Is my engine choking for air? LQ4, SS2, M6

After a quick look at the files he posted, it's pretty clear kingtextwall followed the rabbit. The engine is fine. The toon is almost stock...seriously, almost everything that matters. And where it isn't stock, it needs help. Torque reading from the ECM is irrelevant with the torque model untouched. And I'd be trusting very little of the data coming through with the ECM voltage dropping into the 10s and 9s at WOT. You've got electrical bugs.

Leave the engine alone. Do a proper diagnosis of the electrical system. Then come back for some toon help. And ignore kingtalon...he went down the rabbit hole with your prognosis without even looking at the data.

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Originally Posted by smokeshow

You sure bro lol

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ICE are remarkably simple things. They are one of the easiest mechanical devices to master.

It is not a difficult or superior achievement to say "One may everything about combustion engines" Because that is not remarkable or unique. Clearly the human race has mastered such devices and likely will progress to phase out gasoline combustion all together as we naturally progress to superior energy sources.

Thus, the IC engine, at least in a modern engineering perspective, is becoming antiquated rapidly. And like any antique, its care, maintenance, and especially performance perspectives, are common knowledge among those engineers who designed such antiques, and any future humans who research them.
In other words, it isn't difficult for any modern-day engineer, who is aware of how large an atom is, to understand how cleanliness is the overriding factor concerning the health of an ICE which is basically the antique in need of preservation and utmost simplicity.

Without the engineering background it would be difficult for a person to understand such things as, the design process of an engine, force analysis, combustion chemistry, computer modelling, fluid dynamics for every system and so forth. Being a PhD can help the engineer learn scholarly aspects yet there is no substitute for experience. It is extremely rare to find both engineering, biological science/chemistry, and experience wrenching, building transmissions, racing and breaking parts etc...

It takes many different types of engineers, people to come together and bring an engine to life. And the engineers do what they can to provide a low cost maintenance and easy to work on platform, at least many manufacturers do (but not all).

And often these engines fall into various types of hands, people who are NOT engineering background, or do not understand the combustion chemistry or biological science of air quality. People that do not know how many parts per million of debris is in the air they and their engine breath and what that debris can do over time to every surface. Very few are measuring their crankcase pressure and flow rates. Even fewer are using particulate counters on incoming airflow path. Fewer still run multiple stages of oil and air filtration to protect their antique engines from hurtling towards the soupy dark conglomerates which are the ultimate fate of all engines, set on a timeline of carbon consumption and random encounters with silicone/dust/metal/whatever.

To summarize, there are two ways to go about protecting our antique ICE.
1. Do what the engineers would want you to do, copy their OEM designs without understanding why. And this is how I have laid out my information to be brief, e.g. paper air filtration, proper crankcase PCV, cleanliness in every port, plug condition and quality, carbon and oil control theory, etc... It is as they would have wanted but without offering explanations as to why.

Or, #2 if you don't trust the OEM engineers or need to understand the reasons WHY they do these things,
2. Get an education in engineering, a master of science and PhD in fluid dynamics, advanced control theory, bioengineering, mathematical methods, advanced mechanics of materials, etc... DO the book work and then UNDERSTAND why you need the paper air filter and pcv and so forth. Why cleanliness supersedes all other details. The information is in the book work, AND the experience. We can build 100 engines and tune 100 engines and come to the realization that only engines that can reach 250,000+ Miles over 20 years end up with mint bearings have had paper air filters and PCV but not understand why those things are essential without doing the book work.

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Originally Posted by smokeshow

And ignore kingtalon...he went down the rabbit hole with your prognosis without even looking at the data.

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I don't need to see the data when we looked at the plugs and compression and realized the injectors are not working properly or there is a couple air leaks to deal with.

Your idea is too early. The engine is becoming carbon'd up the plugs are all over the place and there is some fueling issues related to the mechanical/electrical devices on the engine, Thus beyond a superfluous glance at the tune file there is no reason to start making changes until the plug and compression issues are sorted out. In other words even if there is voltage issues and those are fixed the engine still has potential internal issues to deal with and external devices such as fuel injectors which will still need cleaning.

I've tuned around a hundred engines from various manufacturers around the world, nissan toyota subaru chevrolet vk etc... All engines work the same way. If you bring me an engine to tune the first thing most OBVIOUS thing is to look at the plugs and determine historical evidence of whats been done or not been done properly. Then I give the owner a HUGE LIST of things to sort out before tuning can even begin.

If he brought me an engine with plugs looking like that and I got those compression results I would not even THINK to start tuning or messing with the tune file before dealing with the engine health and cleanliness first. It is natural and common knowledge among experienced professionals who are also engineers. But most people on the forums are not, so they get panties in a wad over 4 minutes of real diagnostics 900 words from a teacher who btw teaches engineering courses at college and doesn't care about punctuation capitalization or the word whom


Despite my arduous tone I really do appreciate you and others on this forum helping people here. You are very helpful but few have a complete picture that OEM engineers had in mind when it comes to antique ICE care and maintenance. I can't force you to learn but if you can stomach a book or two I am recommending some basic undergraduate studies such as statics, strength of materials, thermodynamics, fundamentals of engineering (is a course with several books I teach frequently 130 students at a time), and of course biology and chemistry as necessary basics to give a perspective on the fluids we deal with and their cleanliness.

Lmao. I was an OEM engineer. So keep typing, others are watching :)

So we have a teacher here trying to tell some industry professionals he is better equipped than anyone here to talk about this stuff.

You know what they say.. those that cannot do... teach. :p

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Originally Posted by smokeshow

Lmao. I was an OEM engineer. So keep typing, others are watching :)

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How can you compare being an OEM engineer to 15 years of college? :slap:

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Originally Posted by smokeshow

The engine is fine. The toon is almost stock...seriously, almost everything that matters. And where it isn't stock, it needs help. Torque reading from the ECM is irrelevant with the torque model untouched. And I'd be trusting very little of the data coming through with the ECM voltage dropping into the 10s and 9s at WOT. You've got electrical bugs. Leave the engine alone. Do a proper diagnosis of the electrical system. Then come back for some toon help. .

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Thanks, I didn't notice the voltage drop either. I've had tensioner pully problems and belt slippage in the past, its probably time to upgrade to a new unit instead of loosening it up with PB blaster lol. Ill also go over the wiring as suggested and report back with findings when I get to it. Im glad my $200 junkyard long block with 100k miles on it still has some life in it, but obviously needs a good internal cleaning.

Following.
I tell many who come to me for help or advice.
Those that can, do.
Those that can't, teach.
Half way through my college days studying for engineering I discovered my teachers were idiots and did not know what was happening in the real world. Working for GM I discovered engineers didn't know how to change their own oil or they would have never put drain plugs over cross members or put an alternator between a transmission and engine on the 3.4l OHC Lumina. I wanted to be a different kind of engineer. One who would tell others, "Hey you can't do that, you know how hard it will be to diagnose or repair that part?". Unfortunately or fortunately I was making a 6 figure killing at the dealership although I used to laugh at people 8 hour a day part time jobs.
I have developed a low opinion of engineers over the decades for good reason. Doesn't mean there are not a sh*t ton of good ones. I guess it is like the police. All it takes is one bad apple to paint the entire group as bad. :(

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Originally Posted by 2xLS1

How can you compare being an OEM engineer to 15 years of college? :slap:

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I'm nothing compared to a professor of everything. lol

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Originally Posted by TheMechanic

Following.
I tell many who come to me for help or advice.
Those that can, do.
Those that can't, teach.
Half way through my college days studying for engineering I discovered my teachers were idiots and did not know what was happening in the real world. Working for GM I discovered engineers didn't know how to change their own oil or they would have never put drain plugs over cross members or put an alternator between a transmission and engine on the 3.4l OHC Lumina. I wanted to be a different kind of engineer. One who would tell others, "Hey you can't do that, you know how hard it will be to diagnose or repair that part?". Unfortunately or fortunately I was making a 6 figure killing at the dealership although I used to laugh at people 8 hour a day part time jobs.
I have developed a low opinion of engineers over the decades for good reason. Doesn't mean there are not a sh*t ton of good ones. I guess it is like the police. All it takes is one bad apple to paint the entire group as bad. :(

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This is true in many cases. At the two of the big 3 manufacturers I worked for, I was surrounded mostly by regular textbook engineers who just did their job and went home to non-automotive lives. Many of them, yeah...they couldn't be bothered to change their own oil. Not that I fault them for it - just how some engineers are. But I do feel the best engineers are those who bridge the gap. Guys who can figure out a car problem by looking at lines on a graph OR by using a trained ear. There's just an inexplicable mechanical intuition that comes from experience with both approaches. I do my best to play that part; I just wrapped up my day job designing missile software and I can run out to the garage, pull the transmission and rebuild it if I needed to. I'm not the best at the white collar stuff or the blue collar stuff, but damn if the guys who skillfully dabble in both aren't rare as hell ;)

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Originally Posted by Frank_Castle

Thanks, I didn't notice the voltage drop either. I've had tensioner pully problems and belt slippage in the past, its probably time to upgrade to a new unit instead of loosening it up with PB blaster lol. Ill also go over the wiring as suggested and report back with findings when I get to it. Im glad my $200 junkyard long block with 100k miles on it still has some life in it, but obviously needs a good internal cleaning.

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I didn't really have to look too long before the data started sowing some doubts. That voltage drop could (and hopefully does) mean a poor connection on a primary ground somewhere, which could explain a lot of problems. Unless the engine is making odd noises, while the toon file and data log look the way they do, there is no need to go all six sigma on a 10% compression difference between cylinders. Make sure the supporting hardware is healthy and then if it still runs sub-par like you said, post back up and we can look into it further. Just don't go rebuilding an engine cause some guy who talks a way too much and boasts some big game says to. Pretty sure most of the claims of engineering lectures or whatever are lies anyway - some of the statements he makes are just simply nonsensical, but they might pass as intelligent to those who don't know otherwise. Basically...just assume everyone is full of shit unless they can logically prove otherwise...even me :cool:

I watched a guy run two different cylinder heads on a engine, two totally different compression ratio's make some absurd number on the dyno. His minor difference is compression between all cylinders means pretty much nothing.

I try to be respectful to anyone who is willing to take the time to respond to a question that I pose, even if they do talk down to me. It’s the Internet and that happens. I like to feel like I’m above that. No need for me to flaunt my doctorate (in physical therapy) just to let everyone know I too am intelligent lol. Obviously I don’t do this stuff for a living and don’t ever plan on it, I have my own career path. But I enjoy working on cars and tuning is the next logical step in developing self growth in my hobby.

Sometimes the smartest guy in the room is the one you least suspect.
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