Hello all my name is: Chris
I have a: 1991 GTO 3000 VR4 twin turbo
It has the following issue: car has had new battery ( 2 months ago ) and alternator is working ( battery man come round and tested car running at 14.2 VDC
I also have new type of maintenance battery charger so battery is all ways kept charged while car is not in use.
Was taking it out for the day , started up all ok car had about 45 min run, we played mini golf for about 1 1/2.
Came back to the car and it would not start . just clicking at the dash board , starter did not even try to go.
i put my booster battery on car , then it started all ok.
i am a sparky and i could be wrong but it like the car will not even try to run if voltage is down a little bit.
This should be an easy one to solve for a sparky. Do you have 12v at the starter motor on the thick wire from the battery? If no, check that you have a good tight connection on the battery. If yes, there is a smaller wire that goes to the starter motor. It is a spade terminal which carries the solenoid voltage to engage the starter when you turn the key. This often gets fowled up or even comes off completely. Clean the terminal and plug and this should solve the problem. If you have the turbo model, it is quite hard to get to so you may have to work blind. Remember to disconnect the battery before starting as there is a very high current, live wire going to the starter.
You may have a parasitic earth. Disconnect your battery earth and connect your meter between the earth strap and the earth terminal on the battery with ignition key removed. If you find a current flow you have a parasitic earth flattening your battery. To find the circuit its on start removing fuses one by one until the current flow stops. When it does you’ve found the circuit with the fault. It’s equivalent to leaving your lights on and coming back to a flat battery after a couple hours. Worth trying as it’s very quick and easy to eliminate this potential fault
If a booster pack started the car then I would assume a battery issue , or a charging issue. Check if battery is charging with a multimeter. You should be getting 14v while the car is running across the battery terminals.
If that’s ok then have your battery checked and if that’s ok I would carry out the parasitic drain test that @vtecgrin described. There are plenty of YouTube vids on the process but be careful not to start the car while your meter is in circuit as it wouldn’t handle the starter motor current.
I think most modern cars up to 100ma is norm , but I would be expecting a lot less on older cars so 50/60 ma would sound about right.
I know a standard ac clamp meter wont measure dc current but if you have a dc one you should be fine.