69 912 new engine+starter blowing fuses when trying to start

[Steks]

We've recently gotten our 1969 912 back on the road. The engine was rebuilt, we've rebuilt the carbs, and basically wrapped up a 10 year major resto. After some recent issues with the starter, we replaced it, and now find ourselves blowing a fuse almost every time we try to run it (especially when hot).

Green and Red light come on, car may turn over once (or just pop fuse - 2nd and 3rd fuse down from top), or it will turn over a few times with what sounds like some hydrostatic compression built up and then stop turning over.

After we let it sit for a while, 50% of the time it will turn right over, start and run.

I'm afraid to take the car anywhere where I have to turn it off for fear it won't restart.

I've checked and sanded down the terminals in the fuse box to make sure good contact. Any other ideas?

Thanks!

[Jaems]

1. check your wiring
2. The battery goes to 1-5 on the #1 fuse box.
3. The 2 fuse wire goes to the ignition switch.
4. The 3 fuse wire only goes to the Cigar lighter and the light in the glove box.

So it's a good chance if the wiring is correct and there is not a short in the wiring. Then it may be the ignition switch.

[C. Clark]

Fairly common issue, try here.
912 Board - Search

[Steks]

Thanks guys for the quick response. Any reason by chance why the fuse wire for #2 and #3 would be bridged together? I noticed a wire bridging them.

Really random in that sometimes it starts strong, then the next time it turns over, makes an ugly noise and fuse #3 blows. Thanks again!

[Steks]

This is a picture of the wires

[Jaems]

You need a wiring diagram for the 912 and one for the 69 911. The 69 used two fuse blocks where the 65-68 used one. They never did make a wiring diagram just for the 69 912.

If you do not have a wiring diagram for both cars. You are just spinning your wheels.

[RichardM912]

I am not an auto electrician but, on a 69, I believe that fuses 1 and 2 were not used. They are for electric window lifts on some 911 models.

Fuse holders 1,2,3,4 and 5 should all be live with the ignition off. They are fed from the battery. Fuse 3 serves the cigarette lighter relay, the electric clock, the glove compartment light and the interior lights (operated by the door switches, etc.). It seems that someone has put a fuse into 2 and jumpered its downside to the downside of 3. Can only presume they wanted belt and braces. Perhaps the clock was stopping - known to happen! - and they wanted to be sure it was not a poor connection at the fuse.

[Jerry1]

My skin crawls when I look at the stock wiring. There are 3 or 4 wires under each terminal how do you know which wire could be bad. When I had my car down for restore I completely rewired the fuses. I put in a terminal block with 30 spots every wire has its own test point. And a updated fuse block with 16 instead of 12 fuses. The best diagrams I found were at Dave Hillmans 912 web page.

Wiring Diagram for Early 912

Good luck

[912UK]

you have a wire prob for sure,

if your stuck get an Auto Elctrican it's not worth the hassel they will work in out in a few hours and tidy up the rest.. if your not carefull you could start a fire..

but just check you have the right fuse rated fuses in place.. after than get the yellow pages out and ring about..