123ignition to signal ecu?, or do I need a cranck trigger? Options

[barkamatic]

Purchased a 123 ignition for a D-Jet but due to the difficulty of finding D-Jet parts I have decided to go with an aftermarket system. Probably a silly question, but could I use the FI firing triggers from the distributor for a crank position signal? Thanks in advance.

[Superhawk996]

Bottom line: D-jet injectors are bank fired and shooting fuel into closed intake ports. So not highly accurate.


My third point pertains to FI needs to know crank position and cam position to know when to fire injectors and spark.

In modern FI the cam sensor is driven directly off the camshaft. So cam position is accurately known.

Same for the crankshaft - sensor is usually reading the crankshaft directly.

Position of both the crank and the camshaft needs to be accurate to know when to fire a cylinder.

What you are proposing is (IMG:style_emoticons/default/bootyshake.gif) backwards.

The crankshaft would be inferred across lots of gear lash slop and the absolute camshaft position would be subject to lash (assuming you’re not putting a camshaft sensor directly on the cam somehow). Not ideal.

I’m not saying any of this is impossible, just that inferring crank position via the D-jet trigger contacts isn’t the best design for a FI system.

[barkamatic]

Bottom line: D-jet injectors are bank fired and shooting fuel into closed intake ports. So not highly accurate.


My third point pertains to FI needs to know crank position and cam position to know when to fire injectors and spark.

In modern FI the cam sensor is driven directly off the camshaft. So cam position is accurately known.

Same for the crankshaft - sensor is usually reading the crankshaft directly.

Position of both the crank and the camshaft needs to be accurate to know when to fire a cylinder.

What you are proposing is (IMG:style_emoticons/default/bootyshake.gif) backwards.

The crankshaft would be inferred across lots of gear lash slop and the absolute camshaft position would be subject to lash (assuming you’re not putting a camshaft sensor directly on the cam somehow). Not ideal.

I’m not saying any of this is impossible, just that inferring crank position via the D-jet trigger contacts isn’t the best design for a FI system.

Since I won't know absolute cam position I can't run sequential injection anyhow. I guess I will just have to go to a crank wheel. I thought that since I won't be using the 123 Distributor injector signals to fire the injectors I might be able to use them for a timing signal. But I see what you mean about the tolerance slop. Thanks for your reply.