Warmup and STFT

[DGA]

Hi, new user. Have a stock LS1, turbonormalised, LS2 intake and stock 90mm throttle body. E40 ECU. I can log this problem but have not had time to yet, was trying to get some idea first if possible of what might be happening. Engine starts fine. It fights to keep running and you can't increase the RPM as it won't accept any throttle opening, is too lean I believe. After reaching 90F ECT, the STFT starts to richen it up, goes all the way to about 27, and is able to be throttled after about 10 or so. All this tells me that I need to change the cold, low end enrichment somehow. I have looked over the program for some time but still have had no real idea of what to do. Any ideas?

[IDRIVEAG8GT]

VE isn't tuned right. Re-Calibrate your VE to add fuel to that area so that your STFT are slightly on the rich side of zero when idling warm. -2/-3. You'll then want to go back and set your OL P/N and OL In Gear tables basically back to stock. That should take of the problem you're having.

No worky still? On HPT we ask you post up a tune and log file for us to look at that way we can browse through what's done, find the problem and then give you a guideline on how to fix it.

Cheers.

[DGA]

Thanks for the reply. I ran it today but didn't get a chance to log anything. So, if I open the VE table, can I just lift the low temp, low RPM area up some? Bump that part of the map up and then maybe smooth it or something? Any idea how much if I get STFT up to 27 now, probably needs to be moved quite a bit I imagine?

[IDRIVEAG8GT]

Yeah it's a long ways off, couldn't tell you precisely how much but add 10% to the problem area, smooth, relog, repeat. Your mid range load portion and WOT portion are probably going to need the same amounts of increase.

[DGA]

Trying to make sure I am doing this right. The manifold absolute pressure values confuse me as they are not in negative amounts (manifold vacuum right?) So it seems to me that the idle area vacuum is in the upper left of the table. Correct? One other thing, the higher values in the table correspond to richer fuel values, so on the 3D map, the higher the peaks, the richer.....?

[DGA]

Attached the tune and log files. After I changed the VE table, it was worse. I couldn't keep it running, so from that I am guessing the VE table is an air table, so the higher the leaner, or more airflow. Newbie I know. The attached tuner file is the earlier one I was trying to change, but it would keep running at least.

[DGA]

Anyone? I sort of need to get this working a bit better for tomorrow, can anyone just tell me how to richen the VE table, I still have no real idea which way to go with it.

[G_OCHO]

Did you get your problem corrected? some questions for you, Is this an aircraft engine? Did you purchase a tune from someone familiar with converting auto engines to aircraft operation?

[DGA]

I found the DFCO was active all the time so I disabled it, that made a huge difference. Am now fiddling with things and moving the VE map up slowly which seems to be helping. The DFCO active was because the original harness guy threw a tune in the ECU and didn't pay much attention to the fact that there is no transmission functions here.
This is a stock crate engine with a dry sump added, and it's turbonormalised, no boost.

[IDRIVEAG8GT]

Sorry it took me do long to get back, yes you're doing everything right so far. Keep hacking away at it till you can produce decent fuel trim readings, then we can go over transients if necessary.

[G_OCHO]

With the various changes and configurations you don't have a stock system. Maybe stock components. If you haven't done so need to verify the fuel system and fuel injector data is correct for the injectors installed. Otherwise your time will be wasted on tuning the VE and MAF. I'm not much help on how to check this . I can comment on tuning VE and MAF. I'm new to tuning but just completed my first tune , G8 GT with cam and exhaust mods. I will leave the technical to the Senior Tuners , I can share my recent experience as a first time tuner, hope you find useful.

I followed the posts and information shared within this forum and it works.
Suggestion: follow the tutorial by Bluegoat, or the LS2 tuning guide or Camaro5 they are excellent help guides. I would encourge anyone to first Learn the scanner and making your own histograms and config files, its a tremendous tool to help understand what the ECM is doing and what all these tables and variables are for.

I started with MAF tuning, because it was faster and much easier. Bluegoat explains this very well. Then I worked on the VE table. When I started the engine was extremely lean, would not idle, would not take any gas, just stumble and die. I managed to get 30 seconds of idle data in the histogram using STFT % , I followed the procedures to multiply by % , re-flashed, repeated, repeated, and within 3 or 4 times engine was idling good enough to start driving and filling in more of the table. Once MAF was correct, I followed the VE procedure . I followed Camaro 5 procedure because of the details for virtual VE using BlueCAT. For your ECM I believe the LS2 guide covers this procedure for VE tables. Again once I set ECM for VE only mode engine was very rough and lean, just quickly log data , adjusted table, repeat, repeat, repeat, and quick enough STFTs started to line out. Completed the VE table. Then using WB tuned the WOT MAF. Last was idle minimum air tables. I haven't worked on timing advanced my KR is very minor so I'm safe, I'll work on this next.

To tune VE table, a way to vary the load is helpful, I live in Kentucky so I used a long hill on an interstate and was able to generate increased loading for different speeds. Might be even easier for airplane, chain to anchors and use variable pitch on the prop to change load.

Other comments. I wouldn't spend time on setting up for different fuels, tune for 93 octane or whatever you use, then when all is working it will be straight forward to setup for AVGAS . I saw in your picture headers, if these are open headers, might be carefull about reversion air during idle throwing off the STFT%,.

Bottom line, as IdriveaG8GT commented" Keep hacking away". Just get after it and these STFTs will line out, that was my approach and I found it worked very well. Good Luck.

[DGA]

Thank you for the good advice. Working with HPT seems to be like buying a Holley 850 for the first time and pulling it apart and just changing any parts you find inside without first knowing what they are or what they do. It takes time to learn what does what and affects what area of the engine's range.

The motor is a stock LS1 in that it has the original cam, heads, intake and compression. The turbo system I designed and fabricated to not ever make any boost as I am trying to keep the power down and keep it alive for many safe hours in the air. 300 hp and only weighing 1250 lbs, it is plenty as is.

Can be hard to load the engine, yes. I haven't actually got enough fuel to the motor yet to feel confident to load it much. It has been, and still is really, very lean. The STFT bumps up to 27% quickly at the low end until the LT takes over and zeros it out. I have moved the VE table up a few times, total of 25% now and it's still lean, but managable to actually put the prop on and run it. I can't figure out why it would need so much more fuel than the stock LS1 would have, the headers are 34" long equal length, 2" diameter, those would bump the power up a bit to make it lean maybe. Very little backpressure as it has a 1.48 A/R hot side on the turbo. 3" tailpipe and 2.5" wastegate tailpipe.

If reversion is affecting it, I need to start looking at that I guess. It went into some kind of low power mode today, not sure why, it had the narrow band O2s flipping up and down nicely and the STFT was about zero, so I still don't know why. Low power mode in aircraft is not a good thing, you can't just pull over and call someone on your cellphone to come get you when it stops.......

[camaro1]

wow tuning that engine for an aircraft,,, i woulnt want to be the tuner if it does happen to go into REP during a flight,,, maybe a DBC system would be better as some of the rep diagnostics are hard coded and just tuning the dtc's off wont help rep mode, i would think the baro and map are going to cause issues at different altitudes , maybe?

[DGA]

This plane is pressurised so I like not having another cable going through the firewall to leak air, plus the DBW throttle is so smooth and you have accurate control of the power.

The system is designed to keep sea level pressure at the MAF, so 'theoretically' nothing changes much up to the turbo's critical altitude, which I hope is 29,000 ft. Wastegates are wide open on the ground and slowly close at that height, which is only 4.7 psi, down 10 psi from sea level.

[Speedmaster747]

Would love to see a video clip of that engine!

[DGA]

Here you go http://www.youtube.com/user/DGAlgie?feature=mhee
You can tell how bad it was running on the first engine start video.

[IDRIVEAG8GT]

OP I gotta hand it to you, that's totally badass.

I did some research and noticed that you have a MAF sensor in place, and that your induction system is completely changed compared to that of a normal LS1. Do this,

Fail the MAFby setting MAF fail to zero hz under egine diagnostics, then max out the dynamic airflow enable rpms, and set codes P0101, 102, 103 to MIL on first error. This should essentially shove the engine into Speed Density or true VE mode. It won't reference the MAF for any more fueling calculations and you should be able to tune your VE table through the entire rpm range.

Whenever you fire it the first time like that, you'll know you have an issue with the MAF if it goes way rich. Let me know,

-Rob.

[DGA]

Thanks IDAG8GT. That's what I should have done to start with I bet. I have raised the VE table 25%, so I bet it will start up rich. Will take me a few days to get to do that with all the other work I have going on but I'll get there.

Shouldn't make any difference to the MAF, but if you noticed, I have flipped the throttle body over to get the throttle motor away from the turbo hot side and the radiator header tank. So the throttle blade is feeding air to the top of the intake manifold instead of the normal bottom. Make a difference at low throttle openings, not sure, all the sensing is over at that point except the MAP.

Odds are pretty good that the turbo is feeding a high energy vortex at some place into the MAF and it thinks it's getting far less air than it really is.