Hope someone can help, I have a 1982 firebird that's been converted to a KITT replica. Here's the issue, first 6 months of using it no starting issues what so ever, the past few months have been annoying. I can go out and start the car fine, turn it off go to start it again and its dead, no ignition at all, then all of a sudden the ignition will suddenly work and all will be fine again. Yesterday I got fuel, came out of garage and the car was dead, I fiddled around and nothing, after 20 minutes I took the negative lead off the battery(for the 4th time) put it back on and it suddenly sprung into life. My partner was in the car and he said before it came on there was a click behind the dash....does anyone have any clue what's going on? It's just so random when it does it, can be fine for weeks then bam it happens.
Its not a ground issue either as the main ground in engine bay has been replaced.

 

Id start with the battery and all the wires and connections between the battery and the starter. You could have the battery checked as well. Of all of that is good, Id consider moving on to the starter and the wiring on the solenoid. Its possible there is an issue in that area. This is where the car gets its keyed power from. Intermittent electrical issues so often are ground issues or connection issues. If you rule out a wiring issues, you could pull the starter and replace it. There is also a ignition switch that could fail but that is much less likely, those usually work or don't.

id start w wire/connections/battery then starter. If possible, when its doing it, try and move all the wires and see if anything changes. The good old jiggle test!

i have an 82, they're really incredibly simple cars. So start w the simple stuff first.

 

Appreciate your reply, the batteries are new, all the battery cables are new, the car was fine for about 8 months, I could check for loose wires on the starter, but a faulty starter would not stop the lights working, indicators, heaters etc.
I am seriously baffled as its so random when it does it, I dont understand what the click is behind the dash when the power does come back on....no one seems to be able to help!

 

The main power wires get their 12 volts from the lug on the starter that the positive battery cable is connected to. Check those wires. They can get burnt from being so close to the exhaust. I had to replace my fusible links on those wires...

 

Thankyou, i will try that, though ive just discovered the cars main earth goes from the battery to the engine not the body of the car, so ive rectified this also

 

That's how it's supposed to be routed/hooked up. To the engine block. Smaller gauge wire connects to the body.

 

The negative batt cable IS SUPPOSED TO go from the batt to the engine.

The highest current that flows in the entire electrical system, is what the starter motor draws. The path from the batt to the starter, and back, therefore needs to have the largest wire and the fewest possible connections in it. Which is why the pos cable goes straight from the batt to the starter, and the neg cable goes to the block, which the starter frame is bolted to, and which has less resistance than a length of cable would. I.e. the block makes a better "cable" than a cable would, for that short distance, so they run a short cable from the batt to the block, and let the block handle the current the rest of the way.

Undo your "improvement" and put it back like it belongs. In NO POSSIBLE UNIVERSE is that the cause of your intermittent starting issue. The right answer to an electrical problem is NEVER to hack on the wiring; that just creates more problems.

You have a bad connection somewhere in the car's battery power wiring. It is almost certainly NOT a ground, or negative side, issue. The suggestion to check the fusible links down by the starter is a good place to start. The deal there is, there are 2 Big Red Wires that carry battery from the starter end of the pos cable, into the passenger compartment, and then power everything in the car. The electrical load in the car is split roughly in half between those 2 wires. One of them has a bad connection in it, which kills the power to everything that runs off of it. Those 2 fusible links act like the main circuit breaker in your house, except that instead of just one main breaker, your car has 2.

The "click" occurs when power is restored to something else under the dash at the same time as it is restored to the starting circuit. It is not part of "the problem". It is merely another symptom of the actual underlying problem, along with the no-start, no lights, no heater, etc. Ignore it.

Power flows from the batt cable post on the starter, through the fusible links, through the 2 Big Red Wires, to C100 which is the big square connector below the power brake booster. On the inside of the car from the other side of C100, each of those wires goes to a splice, which distributes battery to all of the places that it needs to go; the fuse box, ignition switch, headlight switch, and so forth. Since multiple things go out when the intermittent strikes, the fault is somewhere between the batt and those splices, such that all destinations served by the one splice lose their power. The fusible links are the prime suspect, followed by C100. The wires themselves, and the splices, very rarely fail, except that sometimes the terminals on the wires at C100 can get loose on the wires.