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1993 Infiniti G20 - 167k miles- Alternator problem? Rough Idle develops after car has been running for a while
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Persephonie
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Aug 3, 2012, 1:08 PM
Post #1 of 19
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1993 Infiniti G20 - 167k miles- Alternator problem? Rough Idle develops after car has been running for a while
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Hello Everyone,
Ok, I will start at the beginning. I was pulling out of the driveway one day, and turned on my left turn signal light. I heard an electrical short sound(like a pop, then a crackle), and then three warning lights came on and stayed on while I was driving (the anti-lock, the break, and the check battery/alternator warning light). Now the anti lock break thing wasn't actually on, and the break wasn't actually on, just the warning lights were malfunctioning. When I got to work I checked and all my headllights/turn signal lights were working fine, so I am still not sure what that pop thing was. My boyfriend checked all the fuses, and nothing was popped. Him and another guy that "supposedly" knows about cars told me to not worry about it, that it was no big deal. A day or two later I went to go start my car after work, and it wouldn't turn on. I called AAA and they came and said that my alternator and battery were bad. They did readings on it, and I bought a new battery (since it turns out the previous owner put in the wrong size battery... One that was 25% smaller than it should have been! The AAA guy said it was a battery for a smart car or something small, and I beleive him as you could visually see that it was the wrong size)
So anyways, the atlernator was reading at 12.25 v instead of the 14v-ish that it was supposed to be reading at. Since I didn't want to ruin my new battery, the next day I went to the mechanic and he said my alternator was bad. I left the car there, and it was replaced with a remanufactured one. I get in the car to drive off, and okay so when you turn on the car all those warning lights are supposed to flash and then turn off. So now all the lights would turn on when I turned the key, then turn off, EXCEPT for the check battery/alternator light. It wouldn't come on at all, ever. I was really suspicious that maybe they did a botch job and disconnected the warning light so that I wouldn't be the wiser, so I bought a multimeter after doing some research online.
I didn't have time to check it though for a week, since I have been working and all that. But the car hasn't been running right. I turn it on in the morning, and it idles fine, the RPMS are around maybe 800-700 range. Then as I run the car more, after about 10 minutes the car is shaking really bad at red lights, the RPMs go down in the 500 and below range. It just runs really crappy and sounds messed up. It is like the first few stop lights it is in the 800-700 range, then once I am getting closer to work the shaking starts even worse at idle. And it sounds weird when I am accelterating too. Just seems like, underpowered, I don't know. So I finally had some time, I pulled out the multimeter and did a test. First, with the car off it was 12.7 volts. I turn on the car and test for dc volts and with the alternator supposedly on, it was reading at 12.28 volts. Then I turn on the a/c, it goes down to 12.08. I tested it twice, and both times it was reading 12.28 v with the alternator on.
So then I am like damn, maybe they gave me a bad alternator. I go to the shop and pop the hood and check again before speaking to the mechanic, and it was reading at 14 volts! So it seems the alternator is turning on and off, or maybe there is something loose.
Anyways, I am wondering why my check alternator/battery light isn't coming on when I turn on the car (as I said, it had previously been on, and then after I picked up the car it was the first thing I noticed. I went to leave after they replaced my alternator and all the other lights flash on startup except that one.)?
Is it likely they cut the wire, or is it possibly an honest mistake? I checked the owners manual and it says it is supposed to flash at startup like the rest of the lights.
Would a failing alternator cause my car to idle poorly after it has been running for a while, or do you think I have a second problem?
I also thought I smelt gasoline a few times, but then there were other cars around so I am not 100% sure. I also just recently, within the past few months, replaced the spark plugs, got an oil change, and replaced the fuel filter.
Maybe I have more than one problem, but I am just very worried and suspicious. When I went up to the first mechanic and showed him my receipt he looked all shocked or idk (maybe because they don't see a woman pull out a multimeter and start talking voltage often, but I did that intentionally in the hopes that if it was a botch job they won't mess with me again.) I thought they might argue with me or something but they hardly even wanted me to speak, there were other customers in the lot and they were just like oh ok it must be the aternator is bad quality, can you leave the car? It seemed they just wanted me to get out of there, epsecially when I mentioned how I was concerned about how the check alternator light doesn't flash at startup. I could barely finish saying what I wanted to say and they were like oh yes just leave the car here and we will figure it out. I didn't make any accusations, I just said that the aternator is working on and off, told them about my readings, and said maybe a wire is loose or something. It is possible that they just didn't want their other customers to worry so wanted me to leave asap, or it could be something else....It has been already 2 hours and I haven't received a call. I left the car and went home as there is no point standing around in the hot sun, and they had a bunch of other customers so I figured it wasn't going to be quick.
I am just really concerned and wondering if it was an honest mistake, or if car warning lights just suddenly stop working? Any insight would be greatly appreciated.
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Aug 3, 2012, 1:21 PM
Post #2 of 19
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Re: 1993 Infiniti G20 - 167k miles- Alternator problem? Rough Idle develops after car has been running for a while
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Out of all that you "told" a mechanic to replace the alternator and should have just stated that you noticed it wasn't charging and to find out why and repair that.
It may have nothing to do with the alternator itself. Check for burnt wiring or connections that may not look right. IMO it isn't going to run properly as volts drop for whatever reason. Do you want to chase it down or take it back and ask for it to be fixed without telling them what to replace?
T
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Aug 3, 2012, 1:49 PM
Post #4 of 19
(4026 views)
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Re: 1993 Infiniti G20 - 167k miles- Alternator problem? Rough Idle develops after car has been running for a while
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OK - Go back and ask why it isn't charging. Yes, it could be a loose belt which would have to be removed to replace and should be known on tight enough or tensioned enough with replacing an alternator up to requiring a new belt if old one is junk or stretched too much to be right. If it behaved for the shop when finished and pulled this again it will have to be looked at again.
Why the "popping" is a mystery and perhaps that wrong battery could move or who knows now that it's gone? Back to the shop to inspect + diagnose it is what I suggest.
If it somehow just behaves perfectly in front of them it could be difficult. Do make sure if at all possible to have a full charge to even go back if not too far as battery power alone isn't going to last too long,
T
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Persephonie
Novice
Aug 3, 2012, 3:42 PM
Post #5 of 19
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Re: 1993 Infiniti G20 - 167k miles- Alternator problem? Rough Idle develops after car has been running for a while
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The mechanic called me and said it was a loose wire. I went back and he had a kind of like, black zip tie like thing on the positive battery wire bundle. He said the problem was just that it was loose and that the alternator is fine.
At stop lights I am still having the problem with the car vibrating and the RPMs dropping, though the car seems to have a bit more omph and sounds a little different, a little quieter. Maybe I should just get that wire replaced, Idk.(not sure of the price on that either @.@) I am thinking of maybe going to another mechanic to get a second opinion on everything.
I haven't hooked up the multimeter yet, so I am not sure if it is fully fixed. But I guess I will do that later, I just don't want any more bad news at this particular moment and it is scorchingly hot out right now. I will look at it later, and then maybe just pay for an inspection at another shop to get another oppinion and some troubleshooting done about the vibrations at idle and to see if the wire maybe needs to be replaced.
I have been in many cars and maybe I am just being silly(I hope!), many old cars vibrate. This particular model also has a problem with the engine mounts going from engine shaking, just a poor design or something, Idk. I saw it discussed in forums and reviews of the car. In the past this car had two(of the three) engine mounts go out before I bought it, and they were replaced, so I am not sure. Its probably better to get it checked out since it does seem suspicious.
I have a portable jump starter battery pack thing in my trunk that is fully charged, and also a 50ft outdoor cable so if the battery dies I can jump it one way or another. Then I also have AAA so if that didn't work they would come jump it for free. (though waiting an hour is never fun)
I really wonder what that pop sound was, I guess I will see what happens as I move forward with this. 
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nickwarner
Veteran
/ Moderator
Aug 3, 2012, 3:56 PM
Post #6 of 19
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Re: 1993 Infiniti G20 - 167k miles- Alternator problem? Rough Idle develops after car has been running for a while
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The 20 year old connector on the field coil terminal didn't like being disturbed and when the alternator got replaced it didn't hold well. Seems pretty normal to happen and I see things like that a lot. I don't think they were trying to hose you and shoo you away. Like you said, they had a bunch of customers there. They need to hurry up and get them out of the way in order to get their guys working on the vehicles. You have a meter, test the thing to see what the running voltage is. As you know now, its an easy test. Good job on being willing to buy a meter and learn how to use it. My girl has only even checked her oil one time in the last year because I rode her about it for a whole year. I know she did it because she texted my phone while I was at work to specifically point out that she had. Hasn't done it since though.
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Persephonie
Novice
Aug 3, 2012, 6:12 PM
Post #7 of 19
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Re: 1993 Infiniti G20 - 167k miles- Alternator problem? Rough Idle develops after car has been running for a while
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Yes, it is definitely possible they weren't trying anything, but the check alternator light suddenly not working had me worried. I am very suspcious of mechanics, as my mother has been ripped off. She had some banging noise in the back of her car, and the mechanic kept saying it was this and that. She spent 3k fixing various parts, and it turned out to just be a loose panel in the end. Its so sad. That mechanic ended up getting fired from the shop(I guess there were other sad stories) but I just don't feel confident about not getting ripped off, considering cars are so complex and since as a customer I don't know enough about what is going on so it wouldnt be too hard for someone to rip me off.
I also have a friend whom a mechanic messed up an oil change, the oil drained out of the engine as he was driving out of the shop and now he has some problems. He also got fleeced with someone messing up on a tire job; they stripped the lug nuts and then refused to fix it. He had to pay $500 to get them, as well as a hub, replaced.
Then when I was researching auto shops, I found quite a few that had reviews where girls said they took the car to the shop, got told XYZ would cost $120. Then they had their bf or father go to the same shop with the same car, about the same problem several weeks later (and to the same mechanic at the shop) and they got a $20 less estimate.... Its just very iffy. So yeah, I am very suspcious of foul play, mistakes and lack of responsibility in the auto repair field. I am sure there are honest mechanics out there, but many people close to me have been fleeced pretty bad so I worry.
Yeah, I am willing to buy a meter and all that jazz as I don't want my wallet to get taken for a ride, if at all possible! I have researched some other possible causes of a rough idle and how to test for ohms in certain parts and wires, just Id hate to break an aging wire by testing things randomly. Perhaps it is a vacumn leak, but I certainly don't have a safe device to do that test, and certainly don't like the sound of the carb cleaner method as Id hate to set my car on fire. I guess I am going to send my bf to another shop and see what they say about the idle I suppose. From my research it seems like there are a lot of possibilities, so I am hoping to find a good mechanic that understands the symptoms well, and could pinpoint what is the problem (if there is one) and do so without racking up a huge bill in the process. Though from seeing posts in forums of people spending thousands of dollars and the problem still not being fixed, it seems many mechanics have trouble pinpointing what is wrong as well. @.@ This doesn't bode well......
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nickwarner
Veteran
/ Moderator
Aug 3, 2012, 6:36 PM
Post #8 of 19
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Re: 1993 Infiniti G20 - 167k miles- Alternator problem? Rough Idle develops after car has been running for a while
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Ok hon, you've been taken for a ride and know plenty of people who have as well. We get the horror stories every day here and on the job. Every one of us here are professional mechanics currently or retired. We get accused of a lot regularly because of the bad apples in our profession, and its something we try to get through everyday. We donate our time and knowledge here. Not one of us is paid to help you out. We use the years of knowledge about very complex systems that keeps our rent paid to tell you how to save money. So thats where all of us are coming from.
I see its running rough and you are nervous about spraying carb cleaner to check for a vac leak. Thats ok, err on the side of caution. Here's a low-buck fix you should do anyway just from the age of your car. I want you to go to the parts store and get 5 or 6 feet of each of the popular sizes of vacuum line (there aren't a lot of sizes) which when you buy by the foot costs about dirt. Its just rubber hose and it does decay over time. The quote I always use to explain this to people is the last time I trusted a cheap piece of rubber I got 18 years of child support (which is true in my oldest son's case). Go one piece at a time so you don't get them mixed up. A razor knife or sharp scizzors cuts it well. Replace all of your vacuum lines. Its old rubber 20 years old and if its not leaking now it will soon.
Also remember you have recently had the battery unhooked. Remember the movie Terminator 2? Arnold was a learning computer who grew his knowledge by interaction with people. Your car is similar to that. You have a default set of parameters burned into your hard drive that will allow this car to run. But as it runs for enough cycles it learns more and compensates for things based on how your particular car runs and your driving style in certain models. When you unhook the battery you have wiped out the adaptive memory and taken it back to default. You unlearned all the Terminator learned. So it has to learn again and may take 500-1000 miles to do so. I'm not saying that is the only thing wrong with your car because I can't see it from here, but I wanted you to understand how it works. Does that make sense to you?
Change your vacuum hoses out and double check the voltage before you send your man all over town and spend all the diagnostic fees. Also might want to buy a subscription to Angie's list. Its local and people rate all sorts of area businesses they have dealt with. You can see reviews of car shops in your area and go from there.
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Persephonie
Novice
Aug 4, 2012, 1:55 PM
Post #9 of 19
(3951 views)
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Re: 1993 Infiniti G20 - 167k miles- Alternator problem? Rough Idle develops after car has been running for a while
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Yeah, I imagine it would be frustrating with all the bad apples out there.
I could try to replace some of the rubber hoses, I just would have to look up which hoses are which.
I sent my bf to talk to two mechanics, not to pay the diagnostic fees, but to see what they think and what the fees are. Once I have that information, perhaps we will do a few more checks that we can do ourselves and then go from there.
I have heard that sometimes people unplug the battery to get rid of the adaptive memory, as sometimes if you change something it doesn't recognize the change and runs incorrectly. I can see how it may work the other way too, that without the learnt knowledge it may not run as well.
I must admit the car was running a bit rough at idle even before the fiasco with the battery dying and all this stuff. I just didn't think much of it I guess since it slowly appeared, instead of one day just appearing and being obvious. I am not even sure how much vibration is normal for this car, I have been in many old cars and some do just shake and run for years without breaking down. (though I wouldn't assume I would have such luck  ) I guess I will see what I can do myself and then proceed with testing with caution.
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Aug 4, 2012, 7:05 PM
Post #10 of 19
(3942 views)
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Re: 1993 Infiniti G20 - 167k miles- Alternator problem? Rough Idle develops after car has been running for a while
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Hoses: ">>I just would have to look up which hoses are which.<<"
Just do one at a time. Watch out for any plastic connections as they can be brittle and snap off. Use what works like an X-Acto or small razor and peel them off. As Nick said the stuff isn't expensive just needs to be automotive hose tolerant of the extremes under the hood.
Side note on vibrations: I don't find that absolutely a normal thing just as a car gets older. More indicative of something in need,
T
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Persephonie
Novice
Aug 4, 2012, 9:52 PM
Post #11 of 19
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Re: 1993 Infiniti G20 - 167k miles- Alternator problem? Rough Idle develops after car has been running for a while
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I mean I just need to know which are the vacuum hoses and which are the fuel etc. so I don't disconnect the wrong thing and have a nasty mess on my hands. I found the diagram of the vacuum hose system and took the car to an auto parts place. One of the people there came out and we looked at the hoses and so now I have 6 ft of the hose and will replace the ones I can reach tomorrow. There were some bigger hoses in the diagram but we couldn't figure out where they were in the car so will have to skip it for now.
It looks like the hoses we looked at weren't secured really, they slid off without any resistance. I will see if it helps, but it may not be the problem(when is life ever that easy?). He was suggesting that it may be the idle air control unit that is causing the problem, which perhaps it is since it is during idle that the massage chair turns on.
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Aug 4, 2012, 10:20 PM
Post #12 of 19
(3927 views)
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Re: 1993 Infiniti G20 - 167k miles- Alternator problem? Rough Idle develops after car has been running for a while
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General idea of the maze is vacuum items/hose are smaller and generally don't require clamps. Fuel carrying things are or should be metal except for some evap hose which should really only carry fuel vapor.
Some coolant hose may be used but would usually be a bit larger and use clamps. Any vacuum line to a brake booster is larger and rated or marked on hose.
Diagrams may be messing you up. I may be messing you up - sorry if so. What is suggested is just to replace one section and route it exactly as designed away from moving parts or items too hot which is unlikely to show in a common diagram which probably just show lines of a start and finish line but not how it is placed on/in and around items,
T
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Aug 5, 2012, 6:24 AM
Post #14 of 19
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Re: 1993 Infiniti G20 - 167k miles- Alternator problem? Rough Idle develops after car has been running for a while
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Was worried about that too and didn't make a note strong enough. OP = original poster, if you are unsure of what a line contains or is for even this task could be trouble for you. When in doubt - DONT and get help,
T
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Persephonie
Novice
Aug 5, 2012, 8:14 PM
Post #15 of 19
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Re: 1993 Infiniti G20 - 167k miles- Alternator problem? Rough Idle develops after car has been running for a while
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The diagram I have of the vacuum system is clear, it is from the 900 page maintenance manual that I found in PDF version. Just it was a pain to find the diagram in that 900 page manual.
Everything went fine, we changed out maybe 3 feet of hoses one at a time. Couldn't get to a lot of them though as they are under other things that would be a pain to move. A few were cracked but probably weren't causing much trouble.
Car is still idling the same sadly, no better, no worse. The only change that happened was after we got another oil change last night. It previously had been turning on and holding a start-up idle of maybe 800 before dropping as we drove it. Now it starts up a little over 1,000rpms and then drops again as we drive it. Either way the same problem is there, once the car is warmed up the idle gradually drops and the car shakes at stops. With the A/C on it shakes really badly at stops so we have been just driving with the windows down.
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Aug 6, 2012, 2:00 AM
Post #16 of 19
(3883 views)
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Re: 1993 Infiniti G20 - 167k miles- Alternator problem? Rough Idle develops after car has been running for a while
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Quote ">>A few were cracked but probably weren't causing much trouble.<<"
That sums it up pretty well.
If you wish to have a dependable 20ish year old vehicle you are going to need some experienced help not a 900 page PDF on how things are designed when everything is new.
It would take 9,000 pages or more to cover every possible which way any given item is going to degrade over time and the exposure it has been thru.
I don't think I can help you with this on a website,
T
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Hammer Time
Ultimate Carjunky
/ Moderator
Aug 6, 2012, 3:13 AM
Post #17 of 19
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Re: 1993 Infiniti G20 - 167k miles- Alternator problem? Rough Idle develops after car has been running for a while
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You find navigating a manual is too difficult..............
You can't tell the different between a vacuum line and a fuel line...................
You need to put the tools down and leave this to the professionals
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.
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nickwarner
Veteran
/ Moderator
Aug 6, 2012, 2:41 PM
Post #18 of 19
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Re: 1993 Infiniti G20 - 167k miles- Alternator problem? Rough Idle develops after car has been running for a while
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I'm going to go with them on this one too. The smaller things we have suggested are for someone with at least some underhood experience and general mechanical aptitude. Unfortunately you don't have that right now and may mistakenly damage something expensive accidentaly from ignorance of what you are looking at. It will cost a lot of money to repair that and could possibly injure you. I think you can gain some knowledge and I know a lot of tech colleges offer small night classes for a reasonable fee in general automotive maintenance. Small repairs and familiarity with the underhood parts they cover. Its geared towards a novice who wishes to have a better grasp of what they are looking at under the hood of their cars and gain some confidence to do smaller repairs themselves. The prices for such courses are generally quite reasonable and the first brake job or a few oil changes you can handle yourself will outweigh the costs of it.I would look into it. It is by no means a training course for a professional tech, just some basics and thats where you need to start at right now. You had to crawl before you walked. Car repairs aren't much different.
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Persephonie
Novice
Aug 6, 2012, 9:21 PM
Post #19 of 19
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Re: 1993 Infiniti G20 - 167k miles- Alternator problem? Rough Idle develops after car has been running for a while
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Well, yes I thought I had made it clear in my first post that I didn't know too much about cars. I could have sworn I said that this was my first car before, maybe that was in another post. Idk. But yeah, I have already changed the fuel filter and a few other things without problems. I certainly wouldn't try anything that I thought was potentially dangerous, or that I didn't sufficiently research first. I think that likely I will have to get some diagnostic tests to find out what is the problem as I have already done most of the easier things that I felt confident in doing. Other things I have researched would be too much work, or the potential culprit is too difficult to deal with/reach..
I probably wouldn't, at least at this point, take a course in basic car maintenance. I have been reading a few books and things online to get some familiarity during some of my spare time. It wouldn't be a bad idea, I am just too busy to really invest so much time into it really.
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