Changed battery but still won't start

mjanczura · #1 (**permalink**) 08-12-2012, 05:03 PM

Hi,

I am looking for some tips on what to check next. I hadn't driven the Cobra in a couple months and couldn't get it started. I finally jump started it and then drove for about an hour. I let it cool down and then tried starting it again, but it wouldn't start. I suspected the battery and changed it, but still nothing. When I try to start it I hear it attempting, but I never get ignition. I even tried a second jump start in case the new battery was low, but that didn't do anything.

Thanks for your suggestions.

Mark

PatBuckley · #2 (**permalink**) 08-12-2012, 06:15 PM

Did you check to see if it is getting fuel?

Gaz64 · #3 (**permalink**) 08-12-2012, 06:51 PM

Can you give more info?

No crank or no fire?

mjanczura · #4 (**permalink**) 08-14-2012, 08:09 AM

The engine is cranking, but there is no ignition. Based on your comments it sounds like checking the fuel is the next step.

Would you recommend adding a drop of fuel directly into the carburetor as the next step to try?

Tommy · #5 (**permalink**) 08-14-2012, 08:50 AM

To check for fuel with a carburetor, remove the air cleaner, open the choke so you can see down the throat of the carburetor, and look for fuel going into the throat as you fully open the throttle one time. If you do not see fuel, that is likely your problem (e.g., fuel pump failed, tank empty, etc.). If you see fuel, it is likely an electrical problem.

You say you had to jump start the engine before driving it for an hour. If the battery was really low, driving it an hour might not provide enough charging to get it fully charged. But it should be enough to allow it to jump start again. Unless you are getting strong cranking action from your current battery, I would suspect it.

If you are getting good cranking RPM (i.e., 300-400), pull the distributor cap and see if the rotor turns when the engine cranks. If it does, then you may have a problem with your coil or ignition system (you haven't told exactly what you have).

Clois Harlan · #6 (**permalink**) 08-14-2012, 11:41 AM

Make sure you have a ground going from your battery to your engine block...probably .00 wire should do just fine. Then a nice heavy ground from you block to your frame.

tirod · #7 (**permalink**) 08-15-2012, 08:14 AM

Get a volt meter and check the voltage across the battery terminals. If it's less than 12.3 volts DC it likely hasn't enough juice to spin the motor and get it started. If the car has electronic ignition, the system must have a minimum voltage to power the electronic package, and the car has to spin fast enough the crank sensor can accurately count it - or, it won't start.

Driving the car for an hour does about 30 -40 amps of charging. The battery is rated over 500CCA, at 40 amps an hour - a high rate - it will take over 12 hours to charge up. At the more battery friendly rate of 10 amps, it will take 50 hours to charge.

Put the battery on a float maintainer and avoid the problem in the future. It's no different than a boat at the lake dock. Non use drains the battery. Changing the battery to another one is no cure, especially if that battery has been sitting around, too. A dead battery isn't a bad battery, it only needs a charge.

Once the battery is FULLY charged, then crank it. If it won't start, check to see the carb is squirting fuel down the venturis. If not, the issue is lack of fuel - the pump may have lost prime sitting around for months, and the lines are empty. The fuel pump has to siphon gas from the tank, and that takes cranking it a lot to pull fuel all the way up to the carburetor.

Cars don't sit idle for months well, they are designed to be driven daily. If it needs to sit, it needs to be started and used weekly to make up for it. Otherwise, it should be drained of all gasoline, put on jackstands, the battery removed, and stored. There's not much middle ground. That doesn't stop the clock ticking on all the rubber parts oxidizing due to contact with the air, including upholstery, too. They can't be frozen in time.

L79v · #8 (**permalink**) 08-15-2012, 03:37 PM

CCA is not the same as amp hour rating.

mjanczura · #9 (**permalink**) 08-20-2012, 05:55 PM

Well I got to the bottom of it. It was a problem with not enough fuel for the mechanical pump to get it to the carburetor. As part of this troubleshooting I discovered that my fuel gauge doesn't work. So even though I put in 2 gallons of gas this was insufficient for the pump to generate enough fuel pressure. Thank you for the troubleshooting tips. It helped point me in the right direction.