[Dishy]

Hi All,
I have just finished replacing my old carburetors with a Speeduino 0.4.3d. The basic setup is a 1.5L four cylinder that has been running fine on weber IDF carburetors. I have removed the carbs and replaced them with a fuel injection manifold. I have fitted a 36-1 trigger wheel to the crank, 14point7 SLC Free O2 controller and sensor, Bosch 044 fuel pump and GM temperature sensors. I don't have a cam trigger and I still have the distributor and single coil connected. The single coil timing is controlled by the speeduino.
I have attached the current tune and a quick log I took driving up and down the driveway. I don't know why, but the engine wants a lot of advance and fuel just to idle and I also do not have very much manifold vacuum.
I have wired each fuel injector individually to channels 1A, 2A, 3A, 4A of the Speeduino. I have set 2 squirts per engine cycle alternating and semi-sequential injection. I think this is right for what I have built, but I am not sure. Any advice on these settings would be great.

Dishy

[LPG2CV]

have you disabled any advance weights and vacuum in the dizzy?

where are you taking vacuum from for the map sensor? is it above or below the throttle plate?

[Dishy]

I have not disabled the mechanical advance on the dizzy and there was never any vacuum advance. I think this should work with the mechanical advance in the dizzy roughly matching the advance in the Speeduino. The advance should be controlled by the Speeduino based on the 36-1 crank trigger.

The vacuum is coming from the manifold log between the throttle body and the inlet runners to the individual cylinders. I have attached a photo of the manifold and circled in red where the vacuum port is.

[PSIG]

No. If the distributor advances the signal to Speeduino by 20°, and Speeduino advances the output 20°, your timing will be 40°, not 20°. Attempts to use distributor advance with Speeduino always at 0° (resulting in distributor advance output) is an interesting hypothesis, but testing has not been conclusive or reliable - so far.

[Dishy]

There is no electrical connection from my dizzy to the Speeduino. I need the Speeduino to get its crank timing from the 36-1 trigger wheel. This is what I think I have setup in the trigger setup.

Dishy

[Dishy]

Can anyone confirm that the correct settings for individually wired injectors is 2 squirts per engine cycle alternating and semi-sequential injection?

Also should the injectors be wired to 1A, 2A, 3A and 4A. In the same order as the firing sequence.

[LPG2CV]

The simple test for the over advanced timing is to lock the timing in TS and using a timing light, see if the marks move when reving the engine a little. Have you set the trigger angle using a timing light?

What info do you have / can advise on the injectors. Where did you get them from? Is the engine they came off a simular hp the engine you have put them on?

[Dishy]

I have eventually resolved the issue. I was never able to get semi-sequential to work. I gave up on semi-sequential and have re-wired the injectors in pairs. The engine runs much better now with a VE fuel value of about 45 and ignitionbtiming of about 12-15 degrees.

[PSIG]

Can anyone confirm that the correct settings for individually wired injectors is 2 squirts per engine cycle alternating and semi-sequential injection?

Yes, but after basic tuning, explore 4-squirts per-cycle for benefits. This results in quasi-sequential with one squirt at every cylinder's TDC, and improves fuel distribution in some engine designs. However, it may limit rpm depending on several factors, so we just use that mode and test for results.

Also should the injectors be wired to 1A, 2A, 3A and 4A. In the same order as the firing sequence.

INJ channels always fire 1-2-3-4. These should be cross-wired (INJ1>Cyl1, INJ2>Cyl3, etc) to inject in firing order as shown in the Wiki: