[Andyinfrance]

A project I have in mind is to replace the Magneti Marelli advance ignition units on a 1981 308 GTSi and combing it with replacing the Bosch k-jetronic mechanical fuel injection at the same time,
I want to keep the original plenum chamber so I can change the single throttle body to one with a throttle position sensor, not interested in individual throttle bodies.
The car has tdc position sensor and engine speed sensor from stock that can hopefully be reused?
I’d have to add a MAF sensor and temperature sensor on the inlet, and an O2 sensor on the exhaust, there are no cats or egr to worry about anymore
can anyone recommend what I should be looking at getting ?

[PSIG]

Welcome!

I want to keep the original plenum chamber so I can change the single throttle body to one with a throttle position sensor, not interested in individual throttle bodies.

TPS may be added anywhere in the throttle system that follows throttle movement. This is primarily for acceleration enrichment in MAP systems, or throttle percent in Alpha-N systems. There are many common or creative solutions to adding TPS to existing systems.

The car has tdc position sensor and engine speed sensor from stock that can hopefully be reused?

That would depend on exactly what those sensors, and especially signal patterns, currently are. Most common options are covered. Specifics needed.

I’d have to add a MAF sensor and temperature sensor on the inlet, and an O2 sensor on the exhaust, there are no cats or egr to worry about anymore

Speeduino can use MAP (Speed Density)or TPS (Alpha-N), and does not support MAF or older AFM. Each system has various pros and cons (benefits and detriments) and effectiveness for specific application and project goals. Most requirements are well satisfied with either SD or AN (or "blended"), and most PCB versions include a MAP sensor for either method on-board, or remote sensor option.

I suggest a light once-over reading of the Wiki, focusing on the info that is specific to your components. A second reading with greater focus to grasp concepts and requirements specific to your project. The largest hurdle for most is reading everything about any option, causing more confusion than help in moving forward. Plan your project goals, identify your component types (sensors, injectors, coils, etc), reference the Wiki and Forum posts, and ask questions from there.

[jonbill]

It looks like a 24 tooth crank speed pattern and a 2 tooth cam position pattern.

Is that right? Speeduino doesn't have a decoder for that, but if the cam wheel were to lose a tooth it would match the dual wheel decoder.

[PSIG]

Waiting for confirmation of patterns; but if assumed 24T and 2T, with 3 sensors, then some of the simpler current generic support options could be:
BF = batch fire; S = cycle-timed batch or sequential; NR = not recommended low-res

• Fuel-only, ignition as-is, signal tap from TDC or ICM pin 10 for ECM input tach
• 24-1, removing one crank tooth and deleting both TDC sensors (BF)
• 24/1, removing one cam tooth and one TDC sensor (S)
• 24-1/1, combining both above, removing 2 teeth and 1 sensor (S)
• 4/0, removing crank sensor, combining 2 TDC sensor signals (BF; NR)

Except for the first option, each assumes distributorless ignition (used only for signals) and multiple coil packs. Note the last one is actually usable, and requires no tooth removal mods, but is low-resolution and also requires waste-spark or individual coils. Higher tooth counts are preferred for transitional timing accuracy. It could be used for temporary system concept tests and first-start stabilization tuning, before committing to distributor delete and coil packs, CNP or COP conversion, etc, but of limited value.

Converting to distributorless multi-coil is more obvious, but retaining the dual distributors could be done with two coil drivers with signal diodes, on alternating output channels (timed WS) using a sequential mode. To simplify the system, I would delete to go distributorless for simplicity, but that's me. User project goals and preferences are needed so we chase the right stuff.

[DaemonCo]

Injection option idea

To keep the plenum and not have to do a custom lower manifold, consider keeping the existing injection system but delete the WUR and change the fuel head to a later KE-Jetronic one from a Mercedes V8





KE-Jetronic is electronically controlled, I have it working on my Porsche 928