911sc backfire if don’t have interior lights

[BobT]

Hi all,

A few days ago I’ve was fighting a left rear taillight fuse popping, and since I couldn’t find my container of spare fuses, I decided to “borrow” one from another circuit. Thinking I didn’t depend on the interior lights much, it seems like a safe choice.

So today I when I went to start the car, it ran rough, and then backfired. I found that if I could get it up to speed it would run ok but when I backed off the throttle and then tried to raise the revs again it would start backfiring. The car has never done this in my 25 years of ownership.

So I turned to the forums here and found, buried in a discussion, that The fuse that is labeled interior lights is also the fuse for the lambada system and the oxygen sensor!

So I just went out to the garage and returned the fuse to it’s original place and voila it’s running great again. So I thought I’d post it here where it won’t be quite so buried and just say what a wonderful resource these forums can be. Left to my own, I would’ve never thought the fuse for the interior lights causing a serious backfire!

[Marc Bixen]

Yes, the same fuse powers the interior lights and the F.I. lambda system, (control unit under the passenger seat.) If you blow the interior light fuse the frequincey valve doesn't operate and the car runs rich.

[john walker's workshop]

Lean.

[Mixed76]

That's insane

Sent from my Nokia 7.1 using Tapatalk

[Marc Bixen]

Woops, end of day, tired thanks John Walker.