98 Tacoma won't start

[bull1112]

My roomate is having some problems. He has a '98 Prerunner RWD, 110,000 miles, 4-banger, and it isn't starting w/out a jump now. He replaced the battery a couple months ago and the starter about 6 months ago. I gave him a jump a yesterday, and he needed one tonight after he got to wal-mart after work (couple starts w/out me!). When we got back to our place, it wouldn't crank after he parked. My guess is its his alternator, but I'm not exactly a car person. Anyone got any ideas or similar stories????

[Brian R.]

Get it running and check the voltage between the battery positive and ground. Should be above 14 volts. If it's around 12 volts, then it's the alternator.

http://www.automotiveforums.com/vbul...d.php?t=166525

[Flash75]

Did your roommate change the battery and starter for the same problem? Does the truck have a hi powered sound system? Does the truck have add on driving lights? Is the truck used primarily for in town stop and go driving with lights and sound system on?

It's a good idea to check the alternator as Brian suggested. The check should be done with all accessories off. There is a Battery discharge warning light in the instrument panel. The light should come on before starting the engine and go out with the engine running. Is the the light on with the engine running and all accessories off? If it is not on the alternator should be ok. Before buying an alternator have the alternator tested to see if it's bad. You stated the truck started a couple of time without a jump? That indicates that something added a little charge to the battery, that was probably during daylight hours Then you say tonight after getting to WalMart it needed a jump and wouldn't start when you got back to your place.

Tacoma alternators are adequate for normal driving conditions but the maximum output is only about 70 amps. At low speeds the output is considerably less. Add a hi output sound system and some driving lights and run around town at nights, the alternator will probably not have enough output to operate all the accessiries and keep the battery charged. To check my theory try measuring the battery voltage with all accessories on. If it is below 12.5 volts your electrical load is too big for the alternator output and the load needs to be reduced, change driving habits or upgrade the alternator.

Clifton