2 questions about converting from l-jetronic to MS

[Spiffy]

Hi there, I have a Datsun 720 pickup truck. It was a carburetted 1600, I swapped that for a 2liter fuel injection and 5speed(Z20E). So I now have the stock l-jetronic fuel only system but with a turbo conversion it's showing it's limits.

1. Stock injectors and the 280zx turbo injectors I'm using are low impedance with a dropping resistor, if I've got this correct the ms2 can drive both high and low imp injectors but do I still need the dropping resistor or do I connect them directly to the ecu?

2. I have already converted to a pertronix ignitor, this can be used as a crank sensor so I can have both fuel and ign control? (locking out mechanical and vacuum advance)

Pic for those interested

[Spiffy]

Anyone?

[dontz125]

The V3.0 & V3.57 main boards have two 10A injector drivers with provision for PWM current limiting. Assuming 4 injectors, I don't see why you couldn't drive the lo-z injectors pin pairs directly.

I don't know enough about the Pertronix ignitions to offer an intelligent comment. What's going on inside?

[DaveEFI]

I have a Rover V8 which started off with much the same injection, and use an MS2 to drive the 8 lo-z injectors directly. Been 100% reliable for many a year.
Personally, I'd fit a 36-1 trigger wheel and crank sensor and go wasted spark. Even the best dizzy is a weak point.

[Spiffy]

The V3.0 & V3.57 main boards have two 10A injector drivers with provision for PWM current limiting. Assuming 4 injectors, I don't see why you couldn't drive the lo-z injectors pin pairs directly.

I don't know enough about the Pertronix ignitions to offer an intelligent comment. What's going on inside?

It's a way of replacing the stock points ignition, there's a sleeve with a magnet you put over the distributor axle and a pickup mounted on the points plate. Which sends the trigger signal to the coil. So in this case that would connect to the MS ecu and the ecu would trigger the coil instead.


So I understand that a trigger wheel is preferred but that requires coil on plug ignition right?
That's more parts and more money and not in my budget at the moment. My main priority now is getting fueling right because I'm running the turbo injectors on the stock market ecu, I've recalibrated the afm so it doesn't grossly overfuel but still 12:1 afr while driving down the highway is far to much.

[DaveEFI]

You can use a crank trigger and retain the dizzy to just send the spark to the correct cylinder. You then don't need to lock the dizzy advance, since it is no longer controlling the spark timing - just sending it to the correct cylinder. However, something like an EDIS coil is cheap used in most countries. Only extra bit needed is a second coil driver - as well as the trigger wheel, etc.