Mike on your last screenshot I see the desired fuel pressure is 2432.3, but it is actually only getting 1534.5. i cant see that being good. What can cause this? This is for anyone who wants to give there $.02. thanks.
Mike on your last screenshot I see the desired fuel pressure is 2432.3, but it is actually only getting 1534.5. i cant see that being good. What can cause this? This is for anyone who wants to give there $.02. thanks.
Last edited by powermizer; 04-20-2015 at 05:43 PM.
WTF? Holes shouldn't be in that part of your head!
As for tuning guides, the LNF has been well covered by GMTech's posts and CCSOB's LNF Bible thread. As for my contributions, I tried to make them easy to find from any browser by searching "lnf <name of the table no one has mentioned like PID, optimum torque, or optimum spark> hptuners".
As for what I've seen in the other forums, exactly what you're not supposed to do. Idk how many times I've read people with no knowledge of how to tune a DI motor tell C7Z owners that 12.8 is too rich and they should be running 10.5-11.1 and pulling timing. That's just one example.
Here's my config file. It's not nearly as comprehensive as others because I know my other parameters are in check from 500+ logs. But, it gives you the basics.
LNF config update 4.cfg
One other thing I noticed here were long, what I presume to be high gear pulls. I see 100% throttle, but only a 20 mph gain in 10 seconds, like 40ish to high 60s ish mph... Lugging these motors is bad news too. BUT, there are other underlying issues. I will be curious to see what the actual damage is, then we can make presumptions at that point, otherwise they're just ASSumptions.
Regardless, I don't think David did anything particularly negligent, and I hate to see this happen to anyone. TBSteck, the LNF is a very finicky motor, whereas the LS series motors are highly forgiving. The LNF sometimes just fails to fail and it's of no fault to anyone but some weak molecule of metal. Hate to say it, but that's why many people have converted to V8, 2JZ, or have gotten rid of the platform altogether.
Also, there were times where commanded FP was 2,xxx and actual pressure was 7xx!!!!! I am surprised the car didn't shut down, or at LEAST blink something on the dash. And I have never actually seen a lambda of 1.2x.... I still hardly believe the car wasn't in limp mode. Again, I see no fault of this in David's tune, just looking through it briefly. The sudden nature of this screams mechanical failure, unfortunate for both parties involved.
Last edited by mkriebs; 04-22-2015 at 11:29 AM.
I just got the call from the engine guy and he said one piston in particular got a "little" hot. He did say it didn't look like it hurt the piston walls - thank God. I asked him what was his best guess why and it he said it was too lean. Looks like we are just going to replace the piston and cam related sensors ... plus the tune.
mkriebs - All pulls, except the last one when the engine went, were done on pretty flat roads and were only done in 2nd or 3rd gear starting around the 2500 rpm range other gears were at much higher RPM's. It would be nice to put the gear the car is in on the chart and/or gauges display but I'm not sure how to do that. I asked Term2 but he didn't tell me either it can't be done (which I really doubt it) or he just didn't have the time to tell me.
If it was a mechanical failure, the timing is just amazing, no issues for 6 1/2 years, 35,000+ miles then put in a new go fast parts (listed earlier in this thread) and a new tune and everything goes to pots and ruins. Remember this car has been autocross'd and Hillclmb'd since it was born so it wasn't like it was just babied on the street and then we started to race it.
Oh well, stuff happens, life goes on.
To be clear, between the "mechanical failure" or "caused by tune" question, ALL of the logs that were posted showed major issues that any tuner looking at the logs should have seen and raised a HUGE warning flag about. This engine had issues from the first tune David put in it and should have never been driven in that condition. In my opinion, it's up to the tuner to inform the customer of impending doom, no matter who or what is causing it. Had you posted one of those logs on here before the engine blew, I'm betting half a dozen guys would have said to immediately stop driving the car. I certainly don't blame you for that though because like you said, you paid good money to insure that your engine would be safely tuned and logged. It wasn't. Your engine failed because it was operated in a dangerous manner while running with a dangerously out of adjustment engine management system. Period. The End on that subject.Originally Posted by TBSteck
Now on to the next warning flag I'm seeing. (lol. Sorry. I'm just really good at catching signs of "impending doom".) I'm worried about your engine builder. I think you need to proceed carefully with this engine build/repair. I would press him further on a few issues.
First question you should ask your engine builder... What EXACTLY happened to the piston? "Got a little hot" is NOT a diagnosis of failure. That's like when people say "My battery is bad". Why is it bad? Did it stay out drinking the night before? I'd want to know what the exact failure was. In the car repair world, there is something called CCC. It stands for Concern Cause Correction. I'm assuming the ring land broke, which I can explain exactly why it did if you want. The repair order explanation for that should read something like this... "Customer says engine runs rough and smokes." "Technician ran compression test and found 0 pressure on cyl #1. R&R engine, found #1 piston ring land broken resulting in loss of compression. Ring land failure was caused by overly lean mixtures and excessively hot combustion temps from an aftermarket ECM calibration that modified fueling and ign timing." "Installed forged pistons and instructed customer to remove aftermarket tuning and return ECM to stock configuration or engine failure WILL happen again." (lol)
Second question... Please tell me you're not "just going to replace the piston". PLEASE tell me you're not! If the engine is out, I would STRONGLY recommend at least putting forged pistons in it.
Third question... Is he planning on honing or boring the cylinders? My recommendation on that would surprise most, but it's from seeing many failures and successes rebuilding LNF's specifically.
Fourth question... (probably should have been the first) Has he ever built an LNF? I know, I know, he's built racing engines for decades. Do you want me to tell you how many engine builders with amazing credentials I've seen butcher an LNF rebuild? Quite a few. An LNF is NOT like most other engines. Do you want him learning how to do one on your engine?
Sorry to be such a downer! I'm just trying to save you more headache. I've seen plenty of headaches that could have been avoided with a little discussion and knowledge. Just proceed carefully is all I'm trying to say.
I would not recommend changing just 1 piston. The engine is obviously apart and forged Wiseco's are ~$500 so in my opinion it would be dumb not to take the opportunity to upgrade to the forged pistons. Hopefully the cylinders are still round.... If it were my engine, I would also upgrade the rods while it's apart but that's just me.
John - I would appreciate hearing your recommendation on honing or boring for installing the forged pistons. (in the stock size)
Yes it's super easy to show what gear you're in. Go to the "Table Display" and right click on an empty spot and select "insert". Look in "transmission" and you'll find "current gear", select that. Once it's in your table display, go to your Chart Display and right click on it. You can then add that current gear pid to your chart display. Now you'll be able to see current gear in your Chart Display.
BTW, when I'm looking at logs, I'm looking at the Chart Display 80% of the time. Gauges display- never. Table Display- rarely or only to add or take out pids. Histograms- the other 20% of the time I'm looking at histogram data. Even then, there are many times when looking at the traces in the chart display will give you a much better view of the TIMING of an event. The histograms don't always show exactly when something happens so that you can adjust for it at the right time in the tune. (This is info others might benefit from.)
Haha I knew if I said that someone would ask. It seems like 90% of the time on these LNF's when a ring land breaks it doesn't hurt the bore at all. In those cases, what I do is VERY lightly clean up the bores and nothing else. I've seen SO many LNF rebuilds that end up burning oil because guys get too aggressive running a hone or boring the cylinders. Ecotec engines rarely have bore issues. They can go 100k miles with no problems on bore sizing. I recently helped a guy rebuild his LNF that had ~30k miles on it when it broke a piston. He measured the bores and found they were slightly out of specs. He was ready to take the block to a machine shop until I convinced him to just lightly clean up the bores and put the Wiseco pistons in it. (I of course had him file the rings to get the end gaps perfect.)
Why did I recommend against the machine shop? Who do you think can make a straight bore better, Joe machine shop operator on a crappy old machine or GM with it's multi million dollar equipment? And before the piston broke, did the engine have bore issues? Was it burning oil or had bad compression? No. Ecotec's rarely do. And even though he did an awesome job checking the bores with excellent measuring equipment, did he check the bores with the cylinder head torqued down? Nope. So who's to say those out of spec bores wouldn't have been in spec under torque? I trust GM on that stuff. I don't trust them on much, but they do know how to make a good cylinder bore that lasts. On just about all of their engines. I trust them WAAAAYYYYY more than some dork in a machine shop that's never seen an LNF cylinder bore. So my recommendation when an LNF breaks a ring land? DON'T LET ANYONE HONE OR BORE IT. I'd rather guys did NOTHING to the bore than to cut into it in the wrong way, which is what usually happens. Just my opinion. BTW, the guy I helped on that LNF build has been driving that car with NO engine issues or oil burning.
And yes, I would also strongly recommend forged rods and actually also a balance shaft delete kit. NOT the neutral balance shafts, I've had the ZZP one's fail and do a bunch of damage on my engine. Same reason I don't like the ZZP larger fuel pump lobe cams, I've seen too many HPFP's go out shortly after guys put those cams in.
I use the Chart Display while I'm logging and for review afterwards and really only use the Histograms to check fuel trim averages. The good thing about the chart is I can see how everything is reacting while I'm cruising. When I do a WOT pull, I can glance at it afterwards when I let off of the throttle to see if anything was out of whack. I like to look over just after I let off the throttle to see if there was any KR since it takes a couple seconds for the chart to run off of the left side of the screen. I also keep things like KR chart settings to a max of 6 so I can easily tell if it's happening by glancing at the chart. No sense in having KR displaying from 0 to 30.
Thanks for the info John! I've read about the ring end gaps which makes perfect sense to me.
EXACTLY! That's the best way to do it, have the chart display up and running so you can see immediately after a run what it looks like. And yeah, that's another good point about the chart scale settings. I've seen so many guys with the min and max settings so whacked out that they can't see any changes. Setting something like the KR max to a low number like you did makes it super obvious to see when something is wrong. When I'm looking at things like MAF fluctuations at idle, I lower the max levels so that idle airflow fills the whole chart. That way you can really see what's happening clearly. The HPT scanner is an awesome tool, you just have know how to configure it. I do have some config files I could post, but that would take me another hour or so to explain that there are TWO different "config" settings in HPT and the one that most people post is only PART of the config, which is why it doesn't work using other people's configs a lot of the time. lol, let me get off this computer and get something done and maybe some other time I'll get into that!
On your questions:
1st) That was my wording - "Got a little hot", more of a joke then a description. He gave me a more detail explanation but didn't catch it all - I'll call him back and have him repeat it for me to post
2nd) No not just one piston, the whole set and probably will be the forged Wiseco kit ones - stock size
3rd) He said the walls weren't damaged much and he is planning only to do a little honing to clean them up and probably will be in the stock size. Is there a max amount of clearance you should have until you up your size to the +.5mm ones? This is for my curiosity more than anything.
4th) He admitted he hasn't worked on a LNF engine but others that were similar. I know what you are about to say ... my thought too. It isn't a complete rebuild, just a little honing and new pistons and rings. Not touching anything else except all the sensors will be replaced.
He said the rods looked fine and don't need to be replaced. I'm not surprised on this based on what I've read and the speed of the engine when it went.
And thanks gmtech16450yz for saying what others wouldn't, "To be clear, between the "mechanical failure" or "caused by tune" question, ALL of the logs that were posted showed major issues that any tuner looking at the logs should have seen and raised a HUGE warning flag about.", I got no negative response from him. I told him from the very first tune that something wasn't right around the 3000 range and it never missed there or any where before that tune. He should have said something and maybe I could have avoided this mess.
One good thing, I'll get a stronger engine out of this.
As you can guess, I'm looking for another tuner, but as someone said that I probably won't find one here because of what I did ... I'm still trying to figure that out ... I did trust my tuner.
While the specifications probably come with the Wiseco pistons, they're most likely not specific to the LNF. If you do a search on "LNF REBUILD - FORGED ROTATING ASSEMBLY (After broken piston)", you'll find a thread that takes you through several pages (with videos) on the measurements and how to measure them. The thread is located on the skyroadster.com forum and John has given some excellent information there as well.
When it comes to tuning, put your stock calibration in it and run it for a while. Since you've gone through this ordeal, take the time to read through the LNF threads and watch the videos so you'll become familiar with what you can do. I know time is hard to come bye but a half hour or an hour an evening could do a world of good. CSSOB has a starter file to get you going or you could simply compare that starter file to your stock file to see what changes were made and then read some more and start making your own file.
I went through 2 different tuners and fortunately had great luck. I knew a bit about tuning from one of my older cars that I converted from carbs to EFI so I knew about some of the things one should look for while tuning. Working with the tuners helped me to learn about the tuning on the LNF and I've been tuning my car on my own for the past year and have made a lot of improvements. With a little effort and time, you should be able to do the same and when you do need help, it's easy enough to post up a log on here and ask which direction to go.
He is going to send me a picture and I'll post as soon as I get it.
It was highly suggested not to drive my car with the stock tune because of the mods done (listed above) that is why I got a temporary one from DDM so I could move my car around until I got my tune from Term2. Hmmm ...
The reason I wanted someone "professional" to tune my car initially was because I didn't have the time to learn torque tuning until later this year but I wanted to race it immediately. Seems like I'm in between a rock and hard place. I was just hoping to find someone that really knows what they are doing and has the time and interest to tune my car. I really want someone that has tune a bunch of these engines and understands how the engines are treated during an autocross run and how they are run differently during a hillclimb. Plus it would be nice if they knew how to make different tunes based on 92 or 100 octane fuel. For street and autocross we usually use 92 and hillclimbs we usually use 100.
You should run Dave's tune then until you find someone to tune it. The reason that it was suggested to not run the stock tune with your mods is most likely because of your catless downpipe.
If you're doing email tunes, you could probably have Dave tune it.
Here are the pictures of the piston. Like I said it got a little warm.
ommfg!!!
Sorry, I meant to say
OMMFG!!!
Last edited by gmtech16450yz; 04-22-2015 at 05:57 PM.
GEEZ-US!!!! That is FUUGGGLLLLYYYY!!!!!!!!!!!!! Looks more like a melt down....
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