the car:

1988 245

the problem:

i was driving the other day, braked hard, and the motor cut out. the car wouldn't turn over though the lights and radio still worked. 30 minutes of running the hazard lights totally killed the battery. got a jump and drove the car home.

at home, i started the car with a jump, then disconnected the battery with the car running. the car continued to run and the alternator was producing enough power for the lights and radio as well. i replaced the battery and considered the problem solved.

a few days later, i ran a few errands with the car running great. came out of a store, got in the car, and the motor would not turn over. i jumped the battery and drove the car home where it still sits.

i'm guessing this is a wiring issue. however, i visually inspected them and everything looks good. i do have a multimeter, but where and how can i use it to check wiring?

could the alternator be working intermittently?

any thoughts?

thanks!!!!

A no-crank situation could be due to a bad wire going to the starter. It's blue and yellow in colour and goes through the gray fire-wall connector. On a 1988, this isn't so common because they fixed the crumbling wiring harness problem.
If the wiring from the alternator that goes under the engine is O.K. then you may be looking at a bad voltage regulator on the alternator.
http://www.fcpgroton.com/product-exec/prod...category_id/112
Which is not to difficult or expensive to replace.
Check the voltage between fuse #13 or #14 and a chassis ground with the engine off and the engine running. It should be about 12V with the engine off and 13-14V with it running. If it's less than 13V, I'd suspect the voltage regulator. If a new regulator doesn't change anything then it's probably the alternator.

thanks for the suggestions.

i did not suspect the alternator because the car will continue to run with the battery disconnected.

Huh.... I wouldn't do that. The charging system is designed to have a battery in the circuit.

Another possibility. If the alternator is O.K. then there might be something draining the battery like an CD player that is wired so that it is constantly draining power even when the ignition key is turned off.

The voltage regulator could be fried. Disconnecting the battery while the car is running is hard on the voltage regulator.

the draining problem might be it. there is an aftermarket radio installed that must be turned off...

however, the motor died while driving - and then would not crank.

i suppose the initial problem could have been the battery (which i replaced)

and the new problem could be the voltage regulator (that may have been fried due to my ignorance)

It sounds like the radio is wired to a fuse that does not turn off with the ignition key. There is probably a wire that provides a trickle change to the radio and another wire that provides switched power from the ignition switch. If these wires have been mixed up - there's your answer.

i've only had the car a few weeks...

but the aftermarket radio is a very old one (cassette player)! i make sure it's turned off every time i remove the key.

Maybe you should check the Voltages and if they check out, disconnect the radio and see if the battery holds a charge. My daughter had a CD player in her 240 and even though it was wired correctly, there was something electrically wrong with it and it started draining the battery. After we removed it, the battery held its charge.

update:

i put a fully charged, new battery in the car and drove it to a friend's house 40 miles away without problems.

last night, we checked the battery with a charger, and the device said the battery was good. it also said the alternator was faulty.

i took the car to autozone this morning and they checked out the alternator and said it was working perfectly (they checked at the battery terminals). they went to check the battery and the car died. the battery was totally drained.

i put in my spare battery and drove it back to my friends.

i checked the voltage at fuses #13 and #14. with the car both running and not running, fuse #14 shows zero. with the car both running and not running, fuse #13 shows 12.5 volts. so, the voltage regulator may not be functioning properly, but that doesn't seem related to this problem.

so:

1.the battery is great

2.the alternator supposedly works

3.the alternator was checked at the battery terminals - so wiring between the alternator and battery is good

4.the battery terminals are not corroded

5.there is a nice, tight connection between the battery cables and terminals

if the alternator is good, why are my batteries not charging (they both will take and hold a charge from other alternators)?!

any thoughts?

anyone?! anything?!

Generally speaking, these guys that help out in a thread, don't leave you hanging as you post more info. It is the weekend though, and although you and I need to use this time to fix our Volvo's, some of the guys that may be able to help out may be enjoying the weekend. I've learned that there are a few guys here that know EVERYTHING there is to know, but you have to be patient. This is free help, you know.

As for your problem, I'm wondering if you have a loose, or damaged wire that is shorting out somewhere. I had an old celica that had a problem with the wire connecting to the starter that would disconnect every time I took a left turn. On a windy road, the car was on, off, on, off and so on. On a jeep I had, my battery was not fastened down, so on hard braking, the terminal would short as the battery moved forward and touched the framing of the radiator core support.

Wiring problems are no fun, and can exhaust you. Keep checking everything you can, and update the post as you go on in your troubleshooting. You may find the problem yourself, or post something that helps some of the Guru's here help you out. In the end, it helps all of us by doing so.

Good Luck!!!!

update:

i checked and cleaned/wire brushed all the wiring in the battery-alternator-starter system.

while under the car, i noticed a loose wire above the transmission. this wire goes up into the cabin.

the insulation around the wire had crumbled away over a 2 inch stretch, and that loose piece of wire was resting on top of the transmission.

this may be the problem?

i've replaced that stretch of wire.

i'll let everyone know how this turns out.

thanks

Were there burn marks to prove a short? How old is your battery, have you had a cold snap recently?
IE battery may be suspect.

no burn marks.

one week old battery.

no cold snaps.

-----------------------

fixing the exposed wire did not fix my problem!

With the key in the on position (car not running) make sure you have +12v at the small AND large red wires on the back of the alternator. Use the alternator case as your ground point. Make sure the battery light comes on (instrument cluster).

With the car running measure the voltage at the battery terminals, anything much less than about 14.5 means the alternator isn't charging.