Weird unknown problem

Hi,
My car engine won't start a few weeks ago because of a problem that was presumably a bad battery or faulty alternator. So I replaced the battery and the car works fine again... for about 3 days. During those 3 days, I noticed a few thigns:

1. The engine feels weak, the accelertion is slow and there are occasions when I step on the gas the engine revs but the car won't move for like a second.
2. Everytime I use anything that requires electricity i.e. windshield wipers, power lock, power windows, brakes, etc. the headlight dims, the interior lights dim, and the dashboard dims.

The people at Autozone says taht it's probably the alternator, so I brought in the alternator to have it checked out and it was fine. I also did the test where u disconnect the battery while the engine is on, and the engine still runs. One day I turned on my stereo on the drive home from work, turned off the engine, then tried to turn it on the battery was drained and the car won't start. Everything seems to point towards the alternator but strangely the alternator is fine. So I poked around the hood just pushing on random connections then jump started the engine. Suddenly everything works fine. I cranked up the heat, turned on the music and everything but the car does not shut off. On top of that the acceleration feels smooth. So apparently now nothing is wrong that you can notice except for the interior lights still dims a little but not nearly as much as before. I assume the problem has to do with one or more of the electrical wires but have no idea which. Anyone have an idea?

first off which year and drive train do you have.

second off autozone has been known to flub a alternator test up.

also maybe the problem is intermittant and when it was tested it wasn't "acting up."

also how many amps was it putting out when autozone tested it?
i know on my previous camrys, the amp ratings were 75/80 depending on what trim package you have? mike

p.s if you have a digital volt meter you can atleast find out if it is putting out good voltage

"also did the test where u disconnect the battery while the engine is on, and the engine still runs." First of all, don't do this again. This test was OK many years ago, (I did it myself a few times) but on today's cars with many sophisticated electronic devices, it's not a good idea. The voltage spikes created by disconnecting and reconnecting the battery with the car running can ruin some of these electronic devices.

Second, check and clean all battery terminal/posts connections. They should be shiney clean. You can get a tool for cleaning these items at most auto parts stores for a few dollars. I have even seen them at a few of the dollar stores. Just remember to disconnect the negative terminal first and reinstall it last.

Third, make sure the alternator belt is tight. A good rule of thumb is you should have about a half inch of deflection across the belt's longest span, when moderate thumb pressure is applied.

Fourth, you may still have a bad alternator that is causing an intermittant problem. I have seen this happen, especially when the brushes wear down inside the alternator. Keep a watch on things and if it happens again after doing the battery terminal/post cleaning, I would suspect the alternator.

Mike

"So I poked around the hood just pushing on random connections then jump started the engine."

Do it again and see if you can nail down which connection may have been the culprit. Ya, I know you're comfy with it running fine now but, considering how it was 'fixed" there is a good chance it will come back. Better you "break it" in your driveway than have it die out in the cruel world.

Problem update. To answer 2000izusu I have a Toyota Camry 94 XLE. I replaced the battery and the alternator. Today I drove to autozone to get my car's charging system tested again I got there but couldn't start the engine back up. Everyone there seems to think the problem was the alternator so I bought one on the spot and replaced it. Tried to jump start the car it doesnt work. So I opened up the hood and moved the negative terminal on the battery around (just fidgetting with it not remove) and the dashboard lights up and the car could start again. Basically the battery connection had to be moved around until you see the lights for the car to start. So I started the car, drove around fine. I got my brother to come look at my car. We tried to diagnose the problem. My alarm was sounding everytime we touch the negative terminal while the car was off so I disbled the alarm. The problem still persist. The problem is when driving around if i press the powerlock the engine would shut off. If I step on the brakes the engine might shut off sometiems yes sometiems no, same with the heater and everything else electronics they make the lights dim. However, suppose I start the engine, then disconnect the battery, either stepping on the brakes or press the powerlock would shut off the car. My cousin who knows a bit about cars seem to think it is the sensor or a lose ground. But he doesnt know for sure yet.

Problem update. To answer 2000izusu I have a Toyota Camry 94 XLE. I replaced the battery and the alternator. Today I drove to autozone to get my car's charging system tested again I got there but couldn't start the engine back up. Everyone there seems to think the problem was the alternator so I bought one on the spot and replaced it. Tried to jump start the car it doesnt work. So I opened up the hood and moved the negative terminal on the battery around (just fidgetting with it not remove) and the dashboard lights up and the car could start again. Basically the battery connection had to be moved around until you see the lights for the car to start. So I started the car, drove around fine. I got my brother to come look at my car. We tried to diagnose the problem. My alarm was sounding everytime we touch the negative terminal while the car was off so I disbled the alarm. The problem still persist. The problem is when driving around if i press the powerlock the engine would shut off. If I step on the brakes the engine might shut off sometiems yes sometiems no, same with the heater and everything else electronics they make the lights dim. However, suppose I start the engine, then disconnect the battery, either stepping on the brakes or press the powerlock would shut off the car. My cousin who knows a bit about cars seem to think it is the sensor or a lose ground. But he doesnt know for sure yet.
Seems like a faulty/loose negative battery cable is the source of the problem. get this fixed and your car should be ready to go.:smile:

Regards,
Joet/camry

Clean the battery posts and the cable ends to remove oxidation/corrosion. If that doesn't do it, also check your main grounds and the cables themselves as battery acid can make them brittle and fail.

So tomorrow I am going to check the grounds and clean the battery terminals. I only know of one ground near the battery. Where are the other ones?

It sounds like a bad cable to me if your battery connections are all good and tight. Have you modified the oem battery connection in any way for your alarm or an upgraded stereo?

dave mc

The previous owner installed an aftermarket alarm system and a 5-disc changer. Neither works anymore. I just disabled the alarm by pressing the off switch under the driver's side and I don't know about the 5-disc changer because it has never worked. The alarm before it was activated would sound whenver you remove the negative terminal of the battery and reconnect it.

Hi, I forget to mention whenever I remove the negative terminal and touch it back again there is a big spark approximately 5 cm long if that makes any sense. I was reading somewhere and it says if your battery sparks when you do that you may have a short.

I brought the car to a mechanic today and he tested the charging system. We noticed that when the radiator fan comes on the voltage drops then goes back up again. This points to a potential resistance problem where the alternator is fine but corroded or loose cables may be preventing it from putting out maximum power. Other than that, the mechanic says the car is fine nothing's wrong. I do not trust this however because my car still has problems. I think I will now bring it to an electrical auto shop to have them figure it out.

Hi, I forget to mention whenever I remove the negative terminal and touch it back again there is a big spark approximately 5 cm long if that makes any sense. I was reading somewhere and it says if your battery sparks when you do that you may have a short.

I would say if you DON"T see a spark, you have a problem. Don't try this anymore. Voltage spikes can eat the solid state components in the car in a heartbeat. That said, with the problems you have it wouldn't hurt to get the battery load tested. That will tell you the strength and condition of the battery.

Have you changed the negative battery cable yet? The reason everything comes to life when you wiggle it could be two fold. The cable itself could be corroded internaly and loosing continuity or...the fact the cable is making and breaking continuity due to internal corrosion is removing power from the engine and body computers, resetting them.