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Hi,

 

When extending the injector wires is there any polarity to observe?

 

I mean - does it matter if they are possibly reversed? :euro:

 

And same question regarding the coil connections please?

 

Cheers in advance.

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keep them the same polarity as youll certainly kill a few components especially the coils

If the polarity is wrong you'll effectively be trying to close the internal solenoid with each pulse rather than open it - not helpful. Doubt you'll damage anything if it's only for a few seconds / minutes, if say, you're starting the engine to check the idle once finishing your re-wiring.

Prolonged reversal could burn out the relevant transistor in the PTU - but that's just a precautionary hunch.

  • Author

I have been told by the manufacturer (RC Engineering) of my top feed injectors that polarity is not important.

 

There is nothing but a coil inside conventional electromagnetic injectors. Apparently they have done extensive magnetic testing and there is a small difference in the shape of the first pulse when you reverse polarity and this is due to hysterisis. Any trace of this is gone by the 3rd pulse so it is insignificant.

 

There is a significant back EMF when the magnetic field collapses but this is absorbed by either an RC or (more commonly) zener circuit in the ECU. The breakdown voltage of the insulation is typically more than an order of magnitude higher than the back EMF voltage.

 

I am told that if polarity is marked then the mark allows a technician to match the terminal polarity to the terminal of the harness.. just helpful for diagnostics.

  • Author

... This may not be the case for the stock side feed injectors of course...

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