Premium Fuel Switch

[notacarlo]

Question relating to the premium fuel switch.

Is there a way to wire that harness so that the "premium" option is hot all the time? I know what the switch does, but I do not know exactly how it does it.

My switch sleeps with the fishes. It fell apart many moons ago and I installed a LED switch I had on my bench to get by until I found a replacement. Two years later I have not found a replacement. (my BCS blew in half before this, so I could not confirm the drop in boost when the switch is hit)

I do not have any confidence that the LED switch is functioning like the old rocker. I also don't know how to confirm that. Hitting that switch at WOT to see if i get detonation is not on my want to do list. I would rather do a cut and dry "it's on" fix.

Any insight would be greatly appreciated.

Cheers,


Dan

[MikeFleming]

It does two things using relays.

IIRC:
1) It grounds an EEC input pin to tell the EEC to use Premium mode. Regular mode opens the EEC pin.

2) It sends an EEC output pin to the BCS input so the BC output pin on the EEC connects to the BCS. Regular mode opens (disconnects) the BC output wire to the BCS.

This is schematically described in the 1984 SVO Supplement to the Factory Service Manual. Someday I'll scan & post that section after I figure out how to use a scanner.

BTW - all of those switches (three on an 84, 2 on 85+) are the same switch so you can swap in your Fog light switch (just swap bezel).

[notacarlo]

I will swap with fog light switch as they are currently disconnected until I find a lense.

Thanks again....uh, I mean....I knew that.

[MikeFleming]

Thanks again....uh, I mean....I knew that. Nice recovery. Pat probably won't see this one.

[notacarlo]

Sooo.....I swapped the fog light rocker to the premium fuel wiring. It does not light up when selected to premium. Is this possibly because the BCS is disabled?

Or have I maybe opened a whole nuther can of worms. It's probably the worms.

[notacarlo]

The premium fuel switch/fog light swap seems to have worked regardless of the led not lighting up. I can feel the car pull timing during WOT when I flip the switch.

This question has been answered and issue resolved.