Any questions you have before you begin buying, building and installing.
Izzy46 wrote: Mon Mar 13, 2023 5:57 pmI went ahead and washed the PCB in the dishwasher. After it was all cleaned up I put it on the boat and was able to power up the Speeduino without the injector 3 mosfet heating up. :D :D :D
Image I think Speeduino is "top dishwasher rack safe". :lol:
Izzy46 wrote: Mon Mar 13, 2023 5:57 pmWhile everything seemed to be working well, I did notice the injectors clicking after the engine finished cranking. Each time I finish cranking I could hear about 4 injector clicks in quick succession.
That is normal. Speeduino attempts to finish the current cycle if the rpm are high enough but trigger signal is lost. Here is an example of an HEI V8 distributor triggering a DSC conditioner prototype on a v0.4 (the DSC has diagnostic LEDs that flash with signal output), where you can see the effect at higher signal rate (above threshold) then sudden signal stop:
So I made adjustments to the first column of the VE table as well as delaying the injector prime to 2.1 and now she fires up first time every time. A few pops of the throttle and she sounds amazing!! After 10 months of hibernation the beast is finally awake!! :lol: :lol: :lol: 8-) 8-) :D :D

So thanks to everyone for your advice and persistence with my questions, I really appreciate it. :D :D :D

The boat sounds pretty good, there is no smoke and the throttle is pretty responsive. At the moment the idle is sitting a little high at 1500 rpm. This might be due to throttle calibration or the need to change a few more settings.

I still haven't installed a number of the peripheral inputs such as TPS, coolant sensor and o2 sensor. I plan to get that all together and make the computer installation a little prettier and more robust.

A few questions about the peripherals:

Does the TPS need to be connected, does this matter if the MAP sensor is the primary method of gathering information for the computer?

Does the GM coolant sensor need a resistor as in the picture below or can it be install directly? I'm either going to use the current coolant sensor or replace it with this one. ... re-sensor/
Temp_sensor_connection.png (12.1 KiB) Viewed 1405 times
With the wideband o2 sensor it seems there is a heating element that needs to be turned on but not left on with the ignition. Some suggest wiring it with the fuel pump relay and have it turn on when the fuel pump is turned on. I'm wondering why the o2 sensor heater is relevant when it will heat up instantly once the engine is started? I also live in Qatar where the temperature never gets below 20C. Is the heater really necessary?

I'm looking forward to getting into this next tuning stage and hopefully getting out while the weather is good. :)
Great news

If you haven't changed timing in idle regions, I wou,d do that and then adjust idle.

TPS is needed for acceleration enrichment, you need it. Especially on a ski boat.

The GM coolant temp sensor does not need an external resistor.

O2 sensors need the heater. Maintaining a temp range is required for the measurement method. I wire mine to the FP relay. You'll get errors and no measurement without it. The sensing element runs over 1000F, and at idle could drop below that w/o the heater.
Looking at your tune file again, double check the trigger angle. ie, lock timing and make sure with a timing light that the actual timing matches the value set when you locked timing.

I say this because you have a 0* trigger angle set. I tested with a number modules and at least 3 different reluctor types on different distributors. I have never seen one at 0*, they are usually -10 to -30 degrees.

That is not to say yours couldn't be 0*, but that is outside what I've seen, and is an uncommon situation for it to be exactly zero. Locking timing and verifying with a light will ensure no problems.
Alright, I will see if I can get my hands on a timing light. I know in Doha there aren't many cars older than 15 years and I've never actually seen a timing light in a workshop or a shop. Hopefully I don't have to wait on Amazon again :roll:

To understand the timing situation more clearly:

The distributor orientation has not changed from when it was successfully running the old MEFI 4b computer. I'm assuming the old computer had a setting somewhere between -10 and -30 degrees that I'm now trying to replicate with the Speeduino. Is that correct?

If I'm unable to find a timing light locally, is there any other way to set the timing accurately?
I don't know of another way, but perhaps someone else does.

MEFI was likely set up similar, but that is still a huge trigger angle range. Boat engines have been damaged by too much timing, and it doesn't take long once you are on the water. Boats are running near 100% load all the time, lots of drag. Think about how long your car coasts on decel versus your boat. That drag is why boat timing tops out at 34-36 degrees, where cars can use 45 degrees in some areas.

If the timing is too little, you'll never get it tuned as well as it was.

Getting trigger angle right is critical.
+1, you can get it close, but not spot-on. The Trigger Angle is to tell the processor where 0°TDC is, relative to the incoming signal. It must be accurate to use timing tables accurately. This requires a crankshaft position reference, e.g., a crank sensor, timing light, or other reference between action and crank angle.

Yes, a good tuner using acquired skills can adjust timing to best angle without a timing reference, but that is rare and would be unconfirmed angle. Acquiring those skills would be much more costly than borrowing or buying a timing light. ;) Without those skills or light, your engine is running in unknown territory, with unknown (but potentially substantial) consequences. The old ECM could have had any trigger point for its internal purposes (Speeduino can do that), so that is not a good reference assumption that it ran in that position before.

BTW, new cars also often use timing lights for the same and other advanced diagnostic purposes, so local shops or neighbors may have one hiding in a drawer somewhere. I don't use my timing light much on new cars, and not usually for the crank timing, but I do use it for other stuff on new cars, e.g., torque converter function, belt slip, ABS, etc.
I asked my buddy who is a Mercruiser mechanic what the trigger angle is on MEFI, but that is not something he saw in the factory information or scan tool. He says the factory procedure after removing the distributor is to lock the timing in the MEFI (they have a tool for that, or a MEFI scan tool can do it), and then adjust the distributor until timing reads a set angle BTDC. That angle changes with models but is usually 8-12 degrees.

Because it's a purpose built EFI controller, specific to each model there isn't a trigger angle adjustment in the scan tool. The above is how they know the timing is correct given the fixed trigger angle. If there's a boat repair place, check with them for a timing light also.

PSIG, my grandfather was one of those guys that could set timing by ear. I recall once he helped a neighbor do a valve job in the driveway, and then set timing by ear. They were concerned since he didn't use a light; he got his light and checked, he was 1* off :D
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Heh, I can't find it by ear. But I can find the perfect timing with data, with or without a reference. It's just an extension of my tuning methods, in that what runs best and most efficiently doesn't matter if it has numbers attached. That setting is best, and I manipulate from there for base timing, test for cruise, etc.

I agree (with how I tune), that most users could tune better if there were no references, with timing in Klingon and AFRs in the alphabet. :lol: Then there would be no preconceived notion of what it should be, and instead require diagnostic tuning to find what really is optimal. ;)
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