EI and ignition lead proximity/separation

FI and ignition lead proximity/separation

Can FI injector leads and ignition (plug) leads share a bundle/same conduit (firesleeve)? Being able to do so would save me some complexity and clean up that part of the packaging near the bottom of the valve covers. If this has been discussed, I can’t find it and my apologies. Appreciate any insight. Thx.

Freemasm said:

Can FI injector leads and ignition (plug) leads share a bundle/same conduit (firesleeve)? Being able to do so would save me some complexity and clean up that part of the packaging near the bottom of the valve covers. If this has been discussed, I can’t find it and my apologies. Appreciate any insight. Thx.

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I can't think of a reason why they can't. The injectors are just coils that create a magnetic field to move the pintle (think solenoid), so pretty insensitive to inductive noise. They get a full voltage for a few milliseconds to get them moving and then moves to PWM to keep them open. FI will DEFINATELY not affect the ignition.

Freemasm said:

Can FI injector leads and ignition (plug) leads share a bundle/same conduit (firesleeve)? ...

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I wouldn’t do it.

Ref SDS Service Bulletin:


I gather you have EFII brand but in any case one injector wire goes to power and the other goes to the driver inside the ECU box.

Spark plug leads should be run separate & spaced away from all other wiring.
Also, never use the injector fuel lines as routing for the injector wiring.
Coil, temp & crank sensor wiring can be bundled in with the fuel injector wiring harnesses.