Converting Magnetic pickup to Points for tacho

[discostuee]

As the title explains, anyone have any idea how to convert magnetic pickup signal on the new engine ive put in my car to the distributor points pickup signal for the original tacho from the engine previous.

thanks

 

[Sceadwian]

Considering you have provided absolutely NO information of any kind about either the new or old engine car make or model, no we can't help.

 

[discostuee]

sorry, didn't realize you needed the info. though it was a standard thing.

Car: 1991 Toyota 4runner vzn130

Original Engine: 3vze Dissy.

New engine: Holden commodore "VP" v6. No distributor but crank angle sensor. (i think engine is the same as the buick)


thanks

 

[discostuee]

anyone have any idea?

 

[Diver300]

I guess that you have whatever is needed to power the coil.

If there is a crank angle sensor, some type of engine management computer will read the signal from the angle sensor and decide when to fire the coil.

Just connect your tacho to the coil input.

 

[discostuee]

isn't the original tachos run from Negative though? but good point

 

[Diver300]

I think that most modern ignition systems switch the negative feed to the coils, just like contact breakers.

As well as better control of the timing, the electronic systems can control the time that the coil is on in milliseconds, not degrees of crank angle. That means that the coil inductance and the time that the switch is on controls the peak current, not the coil resistance.

The coil generaters a lot less heat so it can be smaller, so in some cars they just put one coil per spark plug straight on top of the plug, so no HT leads to get damp.

 

[bundyloves]

be careful about putting your tacho on the coils of a holden v6 theres a bout 450 volts back emf on the primary side of coils . on the ecu wireing harness there should be a wire with a 12volt square wave signal ( this is to drive a tacho )

 

[power58]

Most of the Buick coil Paks have a Tach output from the module under the coil packs. It will drive a point type tach just fine. My 95 Aurora V8 Engine has 4 coil paks and the module has a point contidioned tach terminal that drives my 1970's Sunpro Tach just fine. If the car did not come with a tach the harness does not connect to the Tach pin.
Check Repair manuals for the Tach term.

 

[Diver300]

be careful about putting your tacho on the coils of a holden v6 theres a bout 450 volts back emf on the primary side of coils . on the ecu wireing harness there should be a wire with a 12volt square wave signal ( this is to drive a tacho )

If the tacho is designed to connect to the primary of a coil, it will be designed to work with the big back emfs. It doesn't matter whether a transistor or a contact breaker cuts the current. Both cause big back emfs.

If you do want an alternative source, the ac side of the diodes in the alternator is a possible place. I was fixing an alternator over the weekend (Fiat Cinquecento, Magneti Marelli alternator) and the ac connections between the windings and the diodes were really easy to get to, just under a plastic cover on the back of the alternator.