How the Motronic EFI Works?

[hoss4659]

IIRC (us old guys use that caveat a lot), the Motronic EFI in the '84 to 89 911's:

1. Is a batch fire system rather than a sequential port injection system.

2.. Some batch fire systems fire every 720* of crank rotation but the Motronic fires every 360*.

If this is not the case can someone please explain or provide a reference that describes how the system works. Thanks

[Joe Bob]

Talk to Ingo. 3.6@cox.net

[drl911]

I can confirm those cars you reference are batch fire injection because when I changed to EFI recently with MS3Pro I was surprised to find the factory injector wiring harness ultimately ended up being one wire for all. I rewired it all for sequential injection supported by MS3Pro.

I am sure there are merits to squirting every 360° vs 720°, but in either case it is only supplying the fuel to the intake runner. The cylinder sucks in what's available when the intake valve opens.

[hoss4659]

Thanks, drl911