[apollard]

Very similar!
Looking forward to trying out the new firmware code (giving individual shots on each channel). Hopefully next week

[apollard]

OK, so I' run into an issue. I can get to 3400 rpm, and then it is like a limiter kicks in. Goes lean, skips, etc. Won't go above 3400 with speedy doing fuel and ignition. I changed to carb and let speedy do just ignition and the problem was still there, but I could go above 3400. Around 3700 it takes back off.

Tried it on the bench. Setup is a drill driving the same distributor, module, etc that is in the boat. At 3400 or so it starts missing ignition and injection pulses.

Attached are current tune and tooth log. Video shows the ignition pattern missing pulses. Excuse the crappy scope, the Tektronix I got had some issues, so back to the seller it went.

https://youtu.be/rfrqlaBHPoc

[apollard]

Standard log - this is on the bench, not in the boat, so not all sensors hooked up.

[apollard]

I've needed to update the thread, but I've been tied up at work - or running the boat.

First, the issue directly above (dropping ignition pulses) is sorted out and it runs great to redline.

I've got it mostly where I want it with the tune. I can crank it cold (well, as cold as the summer gets here) with no additional throttle, and it will warm up idling nicely at 700 rpm or so. Cold start video -> https://youtu.be/SLRkwOEi32A

It holds that idle RPM with no issue now, dropping about 100 RPM when shifted into forward/reverse (only two 'gears' on a boat). I've also been able to lean out the idle some, helping with the smell when idling. It still likes around 13 AFR to idle, but with advanced timing there really isn't any smell. HUGE advance over the carb, where I needed 12.3 or so to idle well.

I've been able to lean it out in the midranges without seeing any signs of detonation. This is a major jump overt the carb, where boat angle cause fuel mixture problems (from changing fuel level in the bowls) - at 1800-2500 RPM on plane, I could never get the carb out of the high 11's AFR, now I run 13.3 or so. I spend a fair amount of time in that range, so I am enjoying the fuel savings.

After I got all that done, I turned Accel Enrichment on. This was a challenge, since there is not much needed at 2000 rpm up, but a lot needed at off throttle. Boats essentially act like a car with a loose torque convertor - put much throttle in off idle and the RPM jumps to 2400 in a second or less. At PSIG's suggestion, I solved this by increasing the VE in the cells just off idle. I also reduced the % AE some and increased the duration of the AE.

All in all, I am Please with how it has turned out. The Speeduino is an amazing system and fantastic community. Boat has never run better!

Current tune file is attached in case someone wants to reference it.

[cristian3500]

Great job !!!

[evo_lucian]

Good work Andre. Its nice to hear all the hard work come together nicely. Truly a well documented build thread that I'm sure will help many down the road

[Carteknik]

Hi, I am new here, Great topic!
Some years ago thought about this, arduino and ecus, glad someone took it to another level!

Have a boat with a mercruiser 3.0, carburador but electronic distributor with I think same gm 8 pin part you have on yours. It's only a 4 cylinder but also think it would benefit a lot from fuel injection.

I got is if I should place injectors individually on intakeanifold. Think this is the best solution and not inject fuel near the carburador.

Any thoughts on this? Should it be possible? Not sure if have space on manifold for that.
Also what kind of injectors would this need?

Will follow your topic! And start buying some components!!

[cristian3500]

Hi,
from the tests I did on my mercruiser 3.0 with megasquirt & speeduino I never been able to find a stable tuning for it.
I think that the problem is on the oem intake manifold that is not working fine with GM TBI.
On other 4 cylinder engine (old volvo penta and fiat) the same system worked fine.
Last year, on intake manifold I wanted to try the 4 injector solution, but when summer arrived I choosed to install the weber 38 carburator (that works really fine).
As next step I wanted to try to use speeduino only for manage the EST ingnition module with MAP sensor.
Maybe I will made some wrong configuration but this is not my main job and I am a simple enthusiast.

[apollard]

Sorry I missed your posts, I had to step away from the project and site for a while. If you are still working on these, post any questions you have.

Boat is still running great.

[apollard]

Hi All -

Checking back in boat has been running well. I did find the cause of the bog above certain throttle openings and RPMs - a flat cam lobe. Fixed that and no issues.

Haven't had time to do much else to her due to a couple of moves to different US states due to the job. But finally settled a little more, and catching up on the changes to Speeduino.

WOW. Lots of changes and new features. Going to set aside some time to update. Especially like the idle timing control, since that is the one area I still seem to have some problems.

Anyway, fantastic work Josh & everybody!