Mechanics

03 WEIRD ELECTRICAL PROBLEMS

2003 Mitsubishi Eclipse • 6 cylinder FWD Automatic • 107,114 miles

I recently bought this car, had an engine scan before buying, came up clear.
Shortly after my car started losing rpms in idle and when I would turn my blinker on, all my gaugues would flash with it.
About a week into it, my car completely lost power and died. Had to get a jump start.
The next day she started fine! Took it to my favorite shop and they couldnt figure out what was wrong after 3 hours of searching, the obvious electrical problems were there, but no idea and no codes coming up.
So, took the car back to the dealer. They said it had to be the battery, they replaced it free of charge. She ran PERFECT for 2 days.
Now shes starting to the blinking gauges again, and when I turn off my AIR, she loses some RPM, but than regains it.
Im good with cars, and Im scratchin my head on this one. I also have a feeling that the same thing is about to happen all over again. Because the battery was apparently not the issue.
Any ideas? Im so stressed and frustrated over this.
Thank you.
P.S. There is also a new alternator, so its not that either.
Avatar
Mscoole77
August 12, 2011.



When the problem acts up again, use an inexpensive digital voltmeter to measure the battery voltage while the engine is running. It must be between 13.75 and 14.75 volts. If it is low, the generator is not recharging the battery. New generators can be defective but more than likely, if the voltage is low, there is a wiring problem that is causing the generator to turn off.

If the battery voltage is okay, follow the smaller positive cable from the battery to the under-hood fuse box and check that connection. They seem to cause a lot of trouble when the nut works loose. Also look at the smaller negative wire where it attaches to the body to be sure it's clean and tight.

Caradiodoc
Aug 12, 2011.
Why dont you get one of those volt meters that plug into your cig lighter so you can monitor the voltage when it acts up. Even with a new alternator doesnt mean you dont have a charging issue.I have replaced water pumps power steering pumps etc on brand new cars just because its new doesnt mean it good. Also make sure the battery cables are clean and tight.

Saturntech9
Aug 12, 2011.
@ cardiodoc- I thought that, but if it was the cables or wires around the battery, wouldnt I have still had the issues as soon as the new battery was on, regardless? Im thinking there is a wire somewhere that is draining the battery, & because it was brand new, it took a couple days to drain it down again. @ Saturntec. They did an alternator test at the first mechanic & its def a good one. & The strange thing is, there are also no codes coming up.

Tiny
Mscoole77
Aug 12, 2011.
Is there a way to test the entire electrical system of a car? Perhaps a certain kind of specialist? & Thanks again for your feedback on this, so appreciated.

Tiny
Mscoole77
Aug 12, 2011.
First of all, you're dealing with an intermittent problem. Those are always the most frustrating to find because you never know for sure if you really found the cause.

Second, you have to do any diagnosis while the problem is acting up. The generator, or whatever is really the cause, is going to test good when the problem isn't there.

Based on your description and the need for a jump-start, it really sounds like a charging system problem. The generator is just one part of the system. The voltage regulator is most likely built in, but there's still wiring to consider.

When they changed the battery, they would have cleaned and tightened the cables. The connections right at the battery wouldn't exactly cause the symptoms you described, although they could prevent the battery from charging completely. A jump-start would take care of starting, but I don't think the dash or turn signals would be affected. Since you noticed the problem occurred when higher current was needed for the signals, that suggests a bad electrical connection somewhere else. The most common cause I read about repeatedly on many brands of cars is that positive wire at the fuse box, but there are many other places for bad connections or corroded splices to occur.

If the things we recommended so far don't pan out and the problem continues to occur, the goal should be to try to keep the problem occurring so it can be found and corrected. Too many people wiggle and poke at things until something "fixes" it, but we know it's not really fixed.

You might not get any fault codes. They are mainly for things that can have an adverse effect on emissions. Low system voltage can do that but the conditions needed to set a related code might not have been met.

The most helpful thing you can do for now is to take the voltage readings at the battery. You might also see what happens when the problem is occurring and you stop the engine. See if the head lights are bright or dim, if the turn signals work, and anything else you can observe. At that point, measure the battery voltage again. You'll read 12.6 volts if it's fully charged. In that case, work your way down the battery wires to the fuse box and body to try to find a place where the voltage drops lower. Leaving the head lights turned during that test will make it more accurate as the current that can't get through the bad connection will make the problem easier to spot.

If you find closer to 12.0 volts at the battery, it is good but discharged. That will prove something isn't working in the charging system.

You might also look at the fuses themselves. Turn signals don't take a lot of current so they really shouldn't cause much trouble in high-current circuits like the smaller battery cables, but in a circuit that is only meant to handle that lower current, a corroded fuse terminal or partially broken wire will be affected greatly by the added current of the signals. I have a vehicle here right now that is missing the cover to the under-hood fuse box. Two of the fuses completely corroded away from the water that sprayed up there. If you push a fuse and the problem clears up, check the terminals for signs of corrosion.

Hope that gives you some more ideas. Holler back with those voltage readings.

Caradiodoc
Aug 12, 2011.
That volt meter in the cig lighter would be very handy you could actually see the voltage at the moment its acting up and while driving to see if it is a charging issue. I wouldnt assume they cleaned the battery cables when they changed the battery you never know. Cardiodoc is right the postive cable is the one most likely to be corroded if they are. Baking soda and water soaking the end in there for about 10 mins followed by a wire brush cleaning works great unless the cable is so bad the acid went down the cable itself. Also the battery can be drained by a bad alternator or diode within the alternator. If the alternator were to fail not all the time it would be failing more times when it got heated from engine then when it was cold.I would also check for corroded fuses and connections like cardiodoc suggested also make sure all the wires to the alternator are tight with the battery disconnected so you dont hurt yourself.

Saturntech9
Aug 12, 2011.
Mscoole77 - did you ever figure this out? I also have a similar problem that I think is an electrical issue. I have a 2003 Mitsubishi Eclipse Spyder Convertible with 159000 miles 6 cyl. Overall the car has been great, no major problems and I've kept up with the maintenance. However 4 years ago I moved to South Florida and started "going through batteries". The garage was saying that batteries don't last as long down here due to the heat but I've gone through 5 batteries in 4 years. That doesn't make senses (fortunately I only paid for the 1st one and all the others were covered under warrantly). I also had my horn go out. The sound got weaker and weaker till it didn't sound any more. I went to Pepboys and bought a new horn and installed it (very simple). Worked fine for a couple of month and then it started doing that again getting real weak sounding and then the "battery went again". New battery and the horn doesn't sound any more. The dealership and Goodyear (where I got the battery) have both done basic electrical/charging tests on the battery, alternator and starter and said it was fine. But I'm convinced there is some electrical problem somewhere. Any ideas?

Tiny
Sloporto
Sep 22, 2011.
I found my problem which was similar. The battery post is tapered and the cable end is straight. It would act like a spark plug arcing across the gap. This is hard on the battery and causes build up on the posts which causes even more problems. My CD player would start spinning and sometimes I would lose everything and have to jump it. I don't like using shims but found them for sale at every parts store so I put them in and that was the end of my problem. They do wear out after while if you work on your car a lot. It would probably be better to replace the cables with tapered ends if you can find them. I could not find a battery with straight posts. I always end with this little note. I could be wrong.

Tiny
Rwhuff
Nov 14, 2012.
Good information but there's something wrong with your battery cables. All top post battery posts are tapered and the positive post is always larger in diameter. I'm not familiar with any kind of shim for battery cables. If you have the thin sheet metal clamps that are common on Japanese cars, those are designed to bend and conform to the post.

Any battery post and cable clamp reamer also has the cutting blades taperd to match the posts. I've never seen a battery with straight posts or had anyone ask for that. Regardless, happy to know you found the problem.

Caradiodoc
Nov 14, 2012.