[apollard]

Apollard I notice that your VE table is leaner at low RPM and mid to high kpa.

Is this for starting or idle recovery purposes?

My idle areas will get you running, but you can't use them as a guide because:
1) My system is a throttle body injection and your port injection won't need the same AFR (you could end up around 13 something, mine needs 12.5);
2) Mine is a larger engine with a higher performance cam in it. Due to overlap, mine idles in the 55-60 kpa range. I NEVER see anything under 45 kpa, even on fast closed throttle. So, there isn't a need to worry about recovery;
3) Frankly, with a home tune the VE numbers are just numbers necessary to get the engine running the best. So, don't think 50 VE really means your engine has 50% volumetric. It doesn't, since there are too many factors not precisely tuned on a typical home setup (like injector characteristics, timing optimization, etc).

I would use this video for getting your idle tune going. It is for MS, but the principle is the same. I use this same process for road engines with mild cams.
https://www.youtube.com/watch?v=Ifd3JTfnJfs

If it hunts on recovery after tuning idle like the above, you need to richen the recovery area a little.

[apollard]

BTW, if it is running well now, autotune might work OK. The same youtuber has an autotune video with good recommendations. Note that the standard CLT filter in Autotune will mean your engine never reaches the filter point. You'll need to change that since your t-stat is probably 160F. I set it to 5F under the t-stat temp.

https://www.youtube.com/watch?v=hi5EHKth1MA

[Izzy46]

Thanks for those recommendations, I'll use them for my next session.

I'm also having a struggle trying to wire the alternator up correctly. The alternator is a Delco 11SI like the one here: https://www.amazon.com/DB-Electrical-AD ... e904010ad0

Basically the documentation says that:

"This alternator will operate properly by connecting only the phase and lamp terminals from the old alternator (These terminals are identified with a “P” and “L” on the voltage regulator connector of the alternator)."

https://www.delcoremy.com/documents/alt ... ch-k1.aspx

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Using the diagram above, I assume ABCD would equate to PLIS. D = P and C = L....? If that is correct it looks like both wires could be hooked to a positive..? I just tried hooking the P up to the alternator output and the L to the ignition. This resulted in the engine not shutting off when I turned off the ignition.

The 11SI marine alternator is a bit obscure with virtually no Youtube videos and Delco Remy documentation only stating
that P should be connected to the "red relay connector" on the wiring harness....

[PSIG]

If this helps:

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[Izzy46]

So I bench tested the Delco Remy 11si alternator and unfortunately it is not longer functional. Time to find a replacement!

I went down to the wrecking yard and picked up an alternator out of a 2007 Silverado.
https://www.amazon.com/ACDelco-15128978 ... B000IZ26J0

Everything matched up perfectly with the Delco Remy 11si except that I've now discovered it takes a square wave input to start the alternator. I'm now exploring my options.....

1) Simulate a square wave to keep the alternator permanently on.
2) Bypass the alternator regulator somehow and have the alternator permanently on.
3) Go back to the scrap yard and find a Chevy alternator that is not computer controlled...... I don't know how likely that is as cars older than 2007 are pretty much non-existent in this country.
4) Order from Amazon and wait a few weeks....

Ideas from anyone experienced with alternators would be much appreciated

[PSIG]

Yeah, those GM alternators are pretty easy. If you just hook them up with no signal, they make like 13.8V. That works but is a bit low for some cases. I would put it on a trickle charger/maintainer to keep the battery topped, and 13.8 will keep it charged fine while you're out. If you were jumping a dead battery, 13.8 would take a looong time to build battery charge even at high-rpm, as an odd example.

If you want to set the voltage to something specific, or get all into charge profiles, we can do that. This was one of the optional functions for my MiniARC (alternator regulator controller) design, that covered most brands and types of alternators, Honda, Mazda, Ford, whatever. You just need the GM function, so we can use a standalone (Nano, ATTiny, etc) if you want a charging profile, or use an unused Speeduino output such as Idle, Boost or VVT if you just want a different fixed alternator voltage. LMK

[Izzy46]

Thanks again PSIG, I was so happy to see your post this morning!! I managed to make a new bracket, find a bigger fan belt and get her installed this afternoon. She's putting out about 13.5v according to the gauge (haven't tested with a multimeter yet) but happy with that for now. I don't know if it's just wishful thinking but the idle sounds a bit smoother too, that random miss that would happen every minute or so seems to have gone too.

Hopefully another water test this Saturday

[Izzy46]

So I went out on a water test this morning with a friend.

The good news:
- The boat starts idles and warms up smoothly
- Tip in is great (more tuning to improve)
- Idle recovery is pretty solid (more tuning to improve)
- The O2 sensor seems to be surviving well

The bad:
- The mysterious random tiny stutter is still there at low RPM.

After doing some low to medium speed runs I passed the boat over to my friend so I could make some adjustments on the go. When he went to take off the boat stalled and wouldn't start again. The fuel pump was not turning on so I bypassed the computer and grounded the relay lead which turned the fuel pump back on. I then discovered that there was no spark. We managed to get towed back to the marina by a big dow boat so it wasn't all bad.

Tonight or tomorrow I'll fish the boat out of the marina and get to work trying to solve this last problem. I'm going to focus on three areas:

- check the Chinese ignition module as these are notorious for failing
- gut the wiring to and from the computer, install new relays and fusebox. I doubt this is the problem but it will make me happier if it's all tidied up
- check the computer to understand why the fuel pump is not grounding
- bench test the coil (if that is possible)

When I was driving back from the marina I realized I may have made a mistake in how I've wired the power supply to the DStage throttle controller and Speeduino. Months ago I soldered the DStage power supply to the back of the Speeduino power supply pins. In my rookie mind I was thinking that the TC would simply piggyback the power from the Speeduino without any issue. I've now realized that Speedy and DStage are wired in parallel and thus the resistance will be halved...?

I'm wondering if this could cause the issues I'm seeing?

[apollard]

Start with checking power to speedy and the module. If power is good, take a tooth log while cranking. If no teeth show, I’d change the module. It can be checked with an ocilliscope but not a multimeter.

[Izzy46]

So she's working well again!

Start with checking power to speedy and the module. If power is good, take a tooth log while cranking. If no teeth show, I’d change the module. It can be checked with an ocilliscope but not a multimeter.

I don't have access to an oscilloscope so I put the old "genuine" ignition module back in and she still didn't start.

I then remembered that the computer had ask me to update Speeduino with 100+ differences, which I rejected. I then remembered that this had caused me a lot of troubles a few months back. I decided to burn my best .msq to Speedy and she started up right away.

Unfortunately she ran terribly so I put another Chinese ignition module in and she now runs beautifully. My ignition module score sheet looks like this:

"Genuine" GM: runs terribly
Indian T-Series x2: DOA
Indian T-Series 3 and 4: yet to try (I have 4 T-Series because of an Amazon mistake!)
Chinese 1: runs at 98%, has the odd miss here and there
Chinese 2: runs almost perfectly. I had her going for around 2 hours without a single miss. At the end of the session the engine stalled twice, I'm not sure whether to put this down to the module or something else...

As a side note, as Apollard suggested, the ignition timing on the Chinese module was 4* increased over the "genuine" module. I'll need to check the latest module again for discrepancies.

So today's session was excellent overall. I got a chance to experiment with TS and the boat is running pretty well.

At the moment I'm a little concerned with the two batteries I have. One of the batteries came out of my Porsche Cayenne as it was unable to turn the engine over despite having more than 12v. The other battery has been in the boat for at least 4 years, which is a long time for a battery to last in this country. The engine cranks well but the voltage drops down to 8v when cranking. I'm thinking if I upgrade the batteries it will give a stronger crank while providing more voltage to the coil for a strong spark at startup. Could bad batteries have anything to do with my terrible luck with control modules?

I'm planning to purchase the registered TS version and go out for another session with the autotune tomorrow. It might be an idea to use the ignition log viewer to get a better idea of what the ignition module is doing....? Is it worth upgrading to the Megalog viewer and TS combo for $75 over just the register TS for $70...? (Probably answered my own question there )

Apollard, your tune has been a guiding light throughout this mission and there are a couple of things I'm wondering.

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Why are the RPM values dispersed widely at the lower range and then come closer together at the higher end of the range. The steps go 400, 400, 400, 400, 500, 600, 700, 700, 600, 100, 200, 100, 100, 100, 100. I would have thought there would be a greater need for finer control at the lower ranges....?

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On the acceleration enrichment you have cold adjustment taper at arctic levels, what is the thinking here?

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Now that I'm up and running, is it worth emulating part or all of your AFR table or should I just stick to 12.8 across the board?

Thanks again for all the advice, it was brilliant to be out on the water again after a full year with a broken boat. It's clear to say that without everyone's help the boat would be in the scrap yard and I'd be signing divorce paper right now.