Car won't Start

86 911 · 86 911's Garage

I have a '76 911 with a '78 3.0 engine and I can't get the car to start!
History:
This morning I connected an instrument light up to the VDO clock which caused a short in the wires as well as a small electrical fire (very scary seeing your car and garage fill up with white smoke). I sorted out the bad wires and put in a whole new instrument lighting loop (that was the previous burnt harness) and I just now finished hooking everything up. Now the problem is the car won't start. It turns over, but simply won't start! At the end of its attempt to start, it lefts out sort of a small, low pitched "poof" noise. What's wrong? Why won't my car start?

curiousone940 · curiousone940's Garage

Given the recent short circuit problem, I would first check the fuse box for a possible blown fuse to the fuel pump. If that's not the culprit, then you're back to the basics...you gotta have fuel and fire to run. Pull a spark plug, ground it to the engine and see if you have spark while cranking. If you have a good spark, then you have a fuel delivery problem. Assuming the car was running OK before the short circuit problem, I would bet that something has occured in the electrical system to create the current situation. It may require more close investigation in the wiring harness to determine where the damage has happened, but if you can determine whether it is a spark or a fuel problem, that should help you in your search thru the wiring harness. Sometimes an electrical short circuit can cause damage further into the wiring harness than immediately obvious to the eye.

86 911 · 86 911's Garage

Thanks for the info M.
I got the car to magically start up. I tested the CDI unit and it was fine, and then hooked up the timing light to check for spark. The light came on and the car mysteriously started

. It seems to run fine, except the idle is at about 1800 RPM

. It's usually at about 950-1000 RPM.

fred cook · fred cook's Garage

Do a vacuum check. It sounds like you may have a small vacuum leak caused by the backfire (poof sound).

86 911 · 86 911's Garage

Thanks for the suggestion, Fred. I will check the vacuum and see if I find a leak. The P.O. disconnected the vacuum line going from the distributor to the air sensor boot. He plugged the hole in the distributor, but the hole in the air sensor for the vacuum line has been connected with another vacuum line leading somewhere in the back left side of the engine. Oddly, my car only has one hole on the air sensor boot to plug the vacuum line in, not two (for the distributor). Is this normal/okay?
Also, why is my car idling so fast?