Lost of power after multiple jumps

Tiny
POORLILRICHGIRL
  • 2003 CHRYSLER PT CRUISER
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 75,557 MILES

Hello, Please I need your help I am a poor college student that bought a pt 03 cruiser limted two weeks ago. Everything was running fine and then yesterday I was driving to school and it died while I was driving just shut off the radio everything went off. It didnt make noise or smell or smoke it was hard to steer if off the road. So I hoped it was the car battery. So I bought jumper cables and had someone with a new car jump my car mulitple times. The first time nothing at all the second the door being ajar would ding and power returned. The third time the car actually started and was on so we ran it for a bit and would press on the gas pedal to reve it. Thought it was all fine but then the moment I took the cales off the other cars battery my car died again no power at all back to square one. Is is the battery or something else? I dont want to waste money I dont have on a battery if I dont have to. Especially b/c theres paper work saying it should have a 84 month battery in it replaced 4/28/10. I need to move my car asap I fear it might have already been towed. I also need to know should I tow it to a shop or is it something I could fix? Thank you for your expertise I just I dont have anyone to talk to or help me with this.

Do you
have the same problem?
Yes
No
Thursday, May 12th, 2011 AT 7:13 AM

3 Replies

Tiny
CARADIODOC
  • EXPERT
  • 28,549 POSTS

First of all, was it hard to steer because the engine stalled or was the engine still running? If it was still running when it was hard to steer, check if the drive belt popped off. That would also cause the battery to run down.

If the hard steering only occurred after the engine stalled, you likely have an alternator problem. The first thing to do is recharge the battery. That can be done with a small battery charger or with another car and jumper cables, but it's going to take a good hour to charge the battery completely. Expect it to have to charge at least 15 to 20 minutes to last long enough to start the engine and drive any distance. With a fully charged battery the car should be drivable for up to an hour if you don't have to turn the head lights on.

Find an inexpensive digital voltmeter to measure the battery voltage while the engine is running, then holler back with that number. I can walk you through the steps if necessary. You can find voltmeters at Sears, Walmart, Radio Shack, or better yet, a Harbor Freight Tools store if you have one nearby. They often have little ones on sale for $2.99 that will work just fine.

With the engine running, the battery voltage must be between 13.75 and 14.75 volts. If it is lower, around 12.0 to 12.6 volts, the alternator is not working. A real common problem with an inexpensive fix is worn brushes inside it. I can post pictures of how to replace the brush assembly but I'll have you do further tests first to confirm that's the problem. That involves measuring the voltages on the two small wires that bolt to or plug into the back of the alternator, but those readings must be taken with the engine running.

I'll be out of town tomorrow so don't think I'm ignoring you if I don't reply right away. I'll be back in the late evening.

Was this
answer
helpful?
Yes
No
Thursday, May 12th, 2011 AT 7:57 AM
Tiny
WOLFDREAMER WOLF
  • MEMBER

Its the alternator, I can tell when you said as soon was you took off the cables, it died. A way you can test it is if you have a fully charged battery and you start it up, then remove the positive cable, and it still runs, your alternator is fine, but vise versa it dies, then the alternator is likely bad.

Was this
answer
helpful?
Yes
No
Friday, May 5th, 2017 AT 11:44 PM
Tiny
CARADIODOC
  • EXPERT
  • 28,549 POSTS

AAAAUUUUGGGGHHH!

WOAH! STOP! For anyone researching this six-year-old post, absolutely do not even think about pulling off a battery cable while the engine is running. Doing so can instantly destroy numerous computers.

Every year I did a demonstration on the alternator test bench for my students to show what can happen when you do that. It was real easy for the voltage to reach over 35 volts. That WILL destroy any computer on the vehicle, the alternator's internal diodes, the voltage regulator, and any light bulbs that are turned on.

The thinking is that if you disconnect either cable and the engine stays running, the alternator must be working but a lot of them will stop working due to the voltage regulator responding to the dips in the "ripple" voltage being produced. That will make a perfectly good alternator appear to be bad so that test is not valid.

If a mechanic is caught pulling this stunt he will typically get one verbal warning. For the second offense he will be fired. It's that big a deal.

Some alternators respond to the high points in the ripple. That momentary higher voltage goes right back to the field winding and creates a stronger magnetic field. That stronger electromagnet creates a higher output voltage which again creates a stronger electromagnet. It's a vicious circle and voltage can keep on rising until something gives out. The main thing that smoothes out that ripple so it doesn't affect the voltage regulator or the alternator is the battery.

Three things are needed to generate the output current. They are a magnet, (electromagnet, in this case), a coil of wire, and most importantly, movement between them. That's why the belt needs to make it spin. One thing that can save you from doing damage by removing a battery cable is not raising engine speed. Generators are relatively inefficient at low engine speeds and their output voltage is less likely to rise to dangerous levels, ... As long as you don't raise engine speed.

One other thing to keep in mind is batteries give off explosive hydrogen gas. Regardless if your generator is working or not there is going to be a big spark when you remove a battery cable with the engine running. Either the alternator's current will be recharging the battery, and that can be up to 20 amps, or the battery is going to be supplying the car's electrical systems, and that can easily be over 30 amps. That kind of current is going to create a big spark when a connection is broken or reconnected. Small arc welders run as low as 40 - 60 amps and look at the sparks they create. The reason we don't hear about more battery explosions is because people are careful to not disconnect the cables when there is current flowing through them. It's also why there are huge warning labels on all battery chargers to be sure they are turned off before connecting or disconnecting them from the battery.

Another common alternator problem is one defective diode out of the six. You will lose exactly two thirds of the alternator's capacity but system voltage will remain normal or it could even be just a little high from the voltage regulator responding to the greatly increased dips in the ripple voltage.

It's always a good idea to wear safety glasses when working around car batteries, but if you still insist on removing a cable while the engine is running, a face shield makes more sense, and have plenty of water on hand to wash any acid off the vehicle's paint.

Ford used to have a really nice generator design that allowed testing right on the back of the unit. Only Chrysler alternators are easier to diagnose. Unfortunately the engineers don't really care about ease of service on GMs and many other brands.

The way you tell if the charging system is working is to measure the battery voltage while the engine is running. It must be between 13.75 and 14.75 volts. There still could be a bad diode though. You need a professional load tester to test for that. Ripple will be very high and the most output current you will get will be one third of the generator's design value. That is not enough to meet the demands of the electrical system under all conditions so the battery will have to make up the difference, until it runs down.

No resolution was ever posted for this problem. The most common cause for intermittent loss of charging on a Chrysler product is worn brushes inside the alternator. Those can be replaced as a ten-dollar assembly, and on many models the alternator doesn't even need to be removed from the engine. Two quick and simple voltage readings on the back of the alternator can verify that failure.

The next best suspect, although some of the related clues or observations weren't present here, is a loose battery wire. Specifically, the smaller positive wire that bolts to the under-hood fuse box. It is common on all car brands for that connection to become loose or dirty. When it makes poor contact, the instrument cluster is usually dark, no lights work, and a jump-start won't help.

There are more things besides the alternator that can cause the charging system to be dead. That's why we always perform a few simple tests first before wasting our customers' money. These systems are so extremely simple, and once the theory of operation is understood, they are very easy to diagnose properly. With a little practice, my students could diagnose any charging problem in a couple of minutes. That's not because I'm so smart. It's because they had learned how to do it properly.

I don't even want to get involved with a car that has had a battery cable removed while the engine is running. It is safer to see if there's gas in the tank by using a lit match, but obviously I'm not recommending that either!

Was this
answer
helpful?
Yes
No
Saturday, May 6th, 2017 AT 1:09 AM

Please login or register to post a reply.

Recommended Guides