[PSIG]

I've checked the output of Ignition 1 (pin7) and it's 0.15v when cracking. I seem to remember that previously it was 1.1v when cranking but am not 100% sure....

Your reading is an average, of mostly 0V an an occasional 5V dwell pulse. The concern is if it is substantially different than before. Compare tune settings and check wiring connections if a problem exists.

I'm hoping that my tune settings are correct and that the attached tune will produce a spark from a GM 8 pin module? I'm wondering if someone could kindly take a quick look to see if the basics are in place?

Offhand, looks OK, if everything is connected for how the tune is set. Are you following the GM7/8-pin setup outline in the Wiki? If the module B pin (Bypass) is grounded, the distributor should fire without signal from Speeduino (self-fire).

I'm also a little puzzled as to why "Trigger Pattern" is set to "Basic Distributor" rather than "GM7X" given that I'm using a GM 8 pin ignition module?

The GM 7x is a special crank/cam signal decoder for certain GM engines with multiple waste-spark coils. It is not related to the GM 7-pin or 8-pin modules. The GM HEI distributor outputs a basic distributor signal, so that's the decoder used.

[Izzy46]

Over the last few days I’ve been working to get the boat started without much luck.

Before the winter break I had the boat running using Dupont connectors, alligator clips and Apollard’s base tune. In hindsight, this was a miracle as the tune was for a v0.3 with throttle body injectors, whereas my setup is v0.4 with port injectors. The boat started consistently but ran very rich and a little rough. The throttle cable was disconnected and I never revved the boat.

Since that time I’ve soldered the relevant outputs to a plug and have everything connected up in a waterproof box. I’ve only connected the injector channels 1 and 2 and the ignition. I plan to connect the water temp, oil pressure, MAP and TPS once the engine is starting consistently.

At the moment I note the following:

- There is consistent and strong spark,
- There is pressure at the fuel rail and the injectors click when I turn the engine over.
- The LEDs for injector channels 1, 2, 3 and 4 light up when the engine is turned over and TunerStudio reads 150 rpm
- The distributor is in the same position as when the boat was running so I’m confident the timing is correct. The B terminal on the ignition module is grounded and the timing is being set by the GM 8 pin ignition control module.

I’m trying to understand why the engine is not firing and my best guess is it’s something to do with the injector setup….

I have eight injectors which are wired into a 4 pin plug. Two of the pins are connected to a red wire and supply 12v to the injectors. There is one pin connected to a blue wire that supplies a ground to 4 injectors and a pin connected to a green wire that supplies a ground to the other 4 injectors.

When I look at the ‘Injector Layout’ on TunerStudio there doesn’t seem to be an option that matches my setup exactly.



Paired: 2 injectors are wired to each channel. The number of channels used is therefore equal to half the number of cylinders. (I have 4 injectors wired to each channel)

Semi-Sequential: Semi-sequential: Same as paired except that injector channels are mirrored (1&4, 2&3) meaning the number of outputs used are equal to the number of cylinders. Only valid for 4 cylinders or less. (I have 8 cylinders)

Sequential: 1 injector per output and outputs used equals the number of cylinders. Injection is timed over full cycle. Only available for engines with 4 or fewer cylinders. (Definitely not this one)

I’m wondering which setting I should use and whether this is the reason the engine is not firing? Could it have something to do with the Trigger Angle (Deg)....?

This is the first time I’ve actually considered how injector and ignition timing work together to create a balanced and running engine. At this point I feel like I’m stumbling around in the darkness, trying different things hoping the answer will hit me in the face!

Once again any ideas are greatly appreciated.

[Izzy46]

After searching forum a little more and reading the wiki it would seem I need to rewire the injector harness to look like the v8 example in the wiki.

https://wiki.speeduino.com/en/wiring/Injector_wiring

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I'll go back to the shop to buy some more marine wire and get to it