Electrical problems, battery and alternator

ATLFAN65

MEMBER
2002 MITSUBISHI LANCER
2.0L
4 CYL
FWD
AUTOMATIC
165,000 MILES

I am recently having problems with some electrical components of my car. My alternator went out 2 months ago and I replaced it with an 80 amp OEM (allegedly) alternator from RockAuto. Things were fine for a little bit, but I recently began observing the obvious signs of a low battery (headlights dimming when windows are being pit up/down, etc) and upon looking at my battery I discovered that my cable on the positive terminal that connects to the starter was very corroded. I bought a replacement cable but when I installed it, the start was constantly engaging. The only thing I could do was disconnect the battery to cease the starter engaging. I went to install the old cable again so I could get to work, however the metal tab that is bolted onto the battery terminal from the actual wire component of the cable broke off, so I had to get a copper connecting piece and crimped it to the wire so that I could connect everything. After hooking everything back up, I used a multi-meter to check my battery with and without a load. Without read 12.4V and with a full load with the car running read 12.6V and was very slowly increasing. I was under the impression that I should have gotten a reading of 13.5-14V if the alternator was fully operating. However, the battery/brake light dash light combination has not come on to alert me to an alternator problem. Would the corroded positive cable cause this voltage reading or is the alternator bad already? I cannot take off the alternator and have it tested at a shop since I then could not drive to the shop, so is there a way to test the alternator with it still on the car with my multi-meter? Also, what would cause the starter to always engage like it did when replacing the cable with a new one? Are these problems connected?

If it helps, I was unable to remove the old starter cable from the bundle of wires so I simply left the old cable in the bundle (both ends disconnected) and rand the new cable alongside the bundle. Not sure if that would cause the problem.

3 Replies

ATLFAN65

MEMBER
13 POSTS

A car parts store can only do a load test with the alternator off of my vehicle. How can I test the alternator using a multi-meter with the alternator on the car?

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Monday, December 15th, 2014 AT 3:11 AM

ATLFAN65

MEMBER
13 POSTS

Do I run the new cable to the starter and also a new cable to the solenoid from the starter? Will the cable have one connection at the battery terminal and one at the terminal and branch off into 2 connections, one for the starter and one for the solenoid?

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Monday, December 15th, 2014 AT 8:23 AM

JACOBANDNICKOLAS

MECHANIC
109,650 POSTS

Hi,

A bad cable can cause this, but it sounds more like the alternator may be failing. You are correct that it wasn't providing the correct voltage when the car was running. As far as the old cable not removed but disconnected, that isn't a problem. Do me a favor, try this load test. It is simple.

https://www.2carpros.com/articles/car-battery-load-test

Also, here is a link that explains how to test the alternator at home:

https://www.2carpros.com/articles/how-to-check-a-car-alternator

Now, I understand why you can't remove the alternator to have it bench tested, but often times a parts store will load test it on the vehicle free of charge. I would try that.

Back to the battery terminals. You do need to replace the one that broke and was repaired. If the starter would engage when the new cable was installed, chances are the new cable which is mounted on the starter, is also touching the S terminal (smaller wire) in the starter. Double check that.

________________________________

Here is a link you may find helpful if it is determine the alternator is bad. Take a look through it.

https://www.2carpros.com/articles/how-to-replace-an-alternator

Here are the directions specific to your vehicle. The attached picture correlates with these directions.

________________________________
2002 Mitsubishi Lancer ES L4-2.0L SOHC
Removal and Installation
Vehicle Starting and Charging Charging System Alternator Service and Repair Procedures Removal and Installation
REMOVAL AND INSTALLATION
GENERATOR ASSEMBLY

pic 1

REMOVAL SERVICE POINT

ENGINE MOUNT VEHICLES WITH ABS REMOVAL
1. Remove ail the power steering hose clamp mounting bolts.
2. Jack up and support the engine assembly, and remove the engine mount.
3. Tilt the engine to remove the generator.

________________________________

I hope this helps. Please let me know if you have other questions.
Take care,
Joe

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