DIY LTCC or similar system for LT1s

[kur4o]

All components were measured and matched with the print on the board and triple checked. Really there is no issues there. All build test were passed successfully.
ICM and coil were unplugged during testing.
The crank table at the temp range of testing almost matches the preset one so that also can be ruled out.

Chain and crank sprocket is almost new 1000 miles on it. Cam sprocket have some signs of usage.

The first start issue is usually when the car was sitting for a long time. It is some fuel issue that I still can`t fix and it is random. If it doesnt start whitin half second I stop cranking and it is starts right on the second try. This happens only if the car have been sitting for a long time.
You can see this in the log1 where the car starts and run on COP. On log2 it fires immediately after stock coil is plugged back and failed earlier on cop system.

I am in no hurry and will check the headers temp on stock coil, than will be able to test next week. ALso will setup some video equipment and will try to duplicate cranking conditions where led fails.

[In-Tech]

Hiya Scott and everyone,
I can't imagine a better tester than kur4o, when shiola happens and you're not there it can feel like a kick in the teeth.

Man, I sure wish I had a vehicle or test engine here to help. All of this is pretty exciting. I'd kick the dog for y'all but I think she's actually starting to like it :D lol

[spfautsch]

The crank table at the temp range of testing almost matches the preset one so that also can be ruled out.

Why not fix it, it takes all of 2 minutes? If the answer is because you're having trouble uploading to the controller you're going to need to figure that out. If you're using the bluetooth serial adapter I would recommend taking it out of the equation so we know we can talk to the board reliably.

Another thing I should mention here is that the FTDI cable I used when testing coils on the bench was extremely sensitive to the EMI generated by the coil firing. If the cable was too close to any source of noise it would crash something in the adapter and stop receiving data until the USB connector was pulled to reset it. I've never had any troubles with the ones I have in the car, but the UART wiring has some distance between it and the coils. Also the FTDI board is way over on the passenger side of the center console.

The first start issue is usually when the car was sitting for a long time. It is some fuel issue that I still can`t fix and it is random. If it doesnt start whitin half second I stop cranking and it is starts right on the second try. This happens only if the car have been sitting for a long time.

Good enough, we'll call it a leaky injector. But if there's even a remote possibility its related to the opti we're likely going to be chasing our tails. The word "random" gives me some cause for concern.

I wouldn't worry about making a video of the leds just yet.

Here's what I'd like you to try if you have time - get the latest build (0.9.39). Configure it for your setup and then uncomment the following options.

#define LOCATE_STRT_POS 1
#define LOGGING 1
#define DISC_ECT_DEBUG 1
#define PROFILING 1

Find and comment out (or just delete) these lines in the main sketch .ino file (diy_ltcc_0_9_39.ino)

#if defined(LOCATE_STRT_POS) || defined(DISC_ECT_DEBUG)
#error PROFILING cannot be used with LOCATE_STRT_POS or DISC_ECT_DEBUG
#endif

Test compile, upload, then disconnect the DTR line. Disconnect the COP coils and the factory ignition module, have the EST line connected to the COP system, and pull the injector fuses so you don't flood it. Connect with a serial console program and then crank the engine over for about 1 second or just slightly less - about a full crank rotation. Let off the key / starter and then send "p" over the uart (with a cr+lf) before turning the key to off. Do this two or three times, turning the key to off in between each. I should be able to at least get an idea from the logs what's happening.

Also, can you verify continuity from each of the coil driver pads (1-8) on the board to pin C of the appropriate coil connectors pls?

ls2_coil_schematic.gif

When I get back I'll try to find a dead side post battery to put in to test slow cranking starts. I ran mine down a few times working on the rewrite, and I don't recall having any troubles related to slower cranking.

[kur4o]

I have planned to do some initial testing and than fix all the small things, Everything seems smooth before the fireworks started.

I hope we figure it out soon. Bad news is I won`t be able to test at least late on Sunday.

Today I did some warm up with stock coil and headers were running cooler for sure. The idle wasn`t that smooth as with the cop system on. Engine seems quieter on stock coil and exhaust smell was much worse.
I suspect 2 reason for the extra heat just by the coils. Some lag at coil firing induce a spark retard. I still have to calculate lag time in ms vs rpm vs crank degree retard.
Reason number 2 is better mixture combustion by the fatter spark and more heat due to all the fuel burning.

I make a log and you can make a comparison of the blms. Stock coil vs COP. BLM comparison clearly shows the meaning of a good spark.

I use stock gm harness and connectors for the coils so everything is good and traced.
Ftdi usb is currently disconnected from controller and I have zero issues logging and updating firmware.

[spfautsch]

I have planned to do some initial testing and than fix all the small things, Everything seems smooth before the fireworks started.

I hope we figure it out soon.

You cannot fathom how much I'd like to figure this one out.

I beg you to focus on the debugging steps I mentioned with the 0.9.39 build. These may give us some hints as to why your controller isn't detecting or staying in sequence properly.

Today I did some warm up with stock coil and headers were running cooler for sure. The idle wasn`t that smooth as with the cop system on. Engine seems quieter on stock coil and exhaust smell was much worse.

I'm intrigued.

I suspect 2 reason for the extra heat just by the coils. Some lag at coil firing induce a spark retard. I still have to calculate lag time in ms vs rpm vs crank degree retard.

No offense, but I think you're chasing vapor trails here. The amount of time the coil per cylinder coils are taking to fire is likely on the order of a few hundred microseconds (us) and is also likely quite similar to that of the stock ignition coil. The controller itself is introducing perhaps a few dozen microseconds of delay. We've discussed this previously. The amount of spark retard this could be generating is negligible unless you're turning the engine > 10K-12K rpm. At idle speeds it's quite certainly irrelevant.

Perhaps there's another logical explanation that aligns with:

Reason number 2 is better mixture combustion by the fatter spark and more heat due to all the fuel burning.

First, let me say how disconcerting it is that you seem to be able to tell a difference in temperature of your exhaust headers when switching between the two ignition systems without instruments (i.e. by feel). In my experience, exhaust manifolds / headers should be hotter than all get out. With mine, within about 15 seconds of engine run time, you'd better not touch them with your flesh or you'll be nursing a blister very shortly. After more than a minute or two of run time you'll be instantly cauterizing the flesh, so blisters may not be able to form.

Working from that tangent, I have to wonder if there's another 3rd possibility: your stock ICM and / or coil have one foot in the grave.

I really, really want to figure out what happened, or at very least what the primary problem is. From your description it sounds to me like either:

a) something causing an immense amount of noise on one of the time-critical inputs

b) something is causing the AVR to reset randomly

c) a damaged AVR

I'm sorry to continue to ask, even though I'm sure based on the questions you've asked that you have a competent understanding of the basics. But I'd really like to see some pictures of the board and the install.

[kur4o]

Still nothing to report.

On the last test with stock coil,
I left hooked the controller and it does seems to function properly when the engine is run on stock coil. All leds flashing with proper operation. I even make a video of the leds when the engine was running with stock coil. Maybe you can PM me some details on upload server.


To rule out any lag in ls coil ignitor or even the coil itself, I plan to do realtime comparison of spark output and film it on tape. Not high speed but hope fast enough to get an idea.

The plan is on warmed up engine to hook #3 coil on the controller and remove #3 from opti. Put on both ends spark plugs and start engine. It will give exact visual confirmation of spark output and duration from stock coil and controller.



I was measuring the radiated heat from the headers by feel, didn`t risk touching them, and the stock coil is some msd unit. You can feel it loose steam on higher rpms but on low it must be strong enough.

[spfautsch]

On the last test with stock coil, I left hooked the controller and it does seems to function properly when the engine is run on stock coil. All leds flashing with proper operation.

PM sent. Out of curiosity, how close to the engine / ignition system (coils and high tension components) is the controller?

The plan is on warmed up engine to hook #3 coil on the controller and remove #3 from opti. Put on both ends spark plugs and start engine.

Another test (assuming this functions correctly with the controller driving one coil) is to run one cylinder from the controller and the other 7 from the distributor. Just make sure to put a grounded spark plug on the loose spark lead to control the severe EMI an unhooked plug wire will cause. Then use a cylinder balance test to see relative strength of combustion.

the stock coil is some msd unit. You can feel it loose steam on higher rpms but on low it must be strong enough.

What about the ICM? Is it also MSD or stock?

[kur4o]

Here is the requested log.

The first 2 attempts the leds show a valid sequence was detected so I tried to duplicate the fail conditions by giving some smaller durations crank time. I did manage to make some of the leds freeze on some of the last attempt. Too bad the phone camera switched off on the most important part. I will try to do another video.