Car won't start, and battery seems charged

Maintenance/Repairs
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1

I have a 1990 Ford T-Bird. My car has been having starting issues for a while. I’m not sure if the seat belt light being on whenever I have the car on is part of the issue, or not. Note that it’s on, even though I have it buckled.

When using Cen-tech digital multimeter, it reads 12.5 - 12.7.

Earlier today, I hooked up a Everstart 750a jump starter. Once red and black clamps were applied, and I turned the Everstart on, the engine icon keeps flashing. Doesn’t become solid. It reads 12.7 - 12.9 v. All 4 battery bars are full.

Overhead light comes on when reattach battery, and re-enter the car. However, the check engine light comes on for a second, and other lights, then all goes out. OR it doesn’t come on. Makes a clicking noise.

From this, it indicates that the battery seems to be ok. Alternator? Starter?

2

If the vehicle has this type if starter relay mounted on the fender well,

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jumper the two large terminals on the relay.

If the starter operates replace the relay.

Tester

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3

Also, change the negative battery cable. It’s probably original. Change it whether you think it’s bad or not.

4

I presume you mean the battery. That’s the correct voltage for a fully charged battery. So pretty good chance both alternator & battery are good. Was that measurement made before first start of the day? Or what had been happening to the T-Bird just prior to that measurement?

I presume it doesn’t crank the engine with key in “start”; i.e you don’t hear the normal rrr rrr rrr sound, instead you hear nothing, or maybe just a click. The problem is likely a faulty starter motor or faulty starter solenoid (as mentioned above). If I had that problem on my Ford truck, my first test would be to measure the voltage at the starter motor with the key in “start”. It should be at least 10.5 volts. If it is, and it won’t crank the engine, I’d replace the starter motor. If less than 10.5 volts, post back what you measure for more ideas. Could still be the starter solenoid. I’ve had to replace that part on my truck before, but never had to replace the starter motor. Truck much older than your T-Bird.

5

Another thing to check is the (IIRC) ground wire (close to the battery) on the fender, they tend to fray and loose good connection, that is the ground for the Processor (ECM), again IIRC…

6

Good point. When I measure the voltage at the starter motor I probe between the terminal on the starter and the starter case, which should have a solid connection to engine and battery ground. . That way any grounding problem will show up in the voltage measurement.

7

A neighbor just had the same problem.

In his case, the battery clamps were rusted. He fixed it by removing the rust.

Maybe he should have used a conductive de-oxidizer oil or grease on the terminals?

8

It has nothing to do with the alternator.
I can think of three options from relatively minor to absolute nightmare

  1. Starter
  2. Wiring
  3. Ceased engine
    Does the battery voltage drop when you attempt to crank? If so - 1 or 3. Otherwise, 2.
9

I’m going out on a limb here and saying the OP was a one and done, OP has not been back on…

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Joined Jul 11, Last Post Jul 11, [Last] Seen Jul 11

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