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Well, so driving my Supra around lately, I had noticed that when I was stopped and idling, sometimes the idle would go below 500ish and the car would struggle and die if i didnt hold my foot on the gas a little bit. The battery being as old as it was, I went and replaced with a yellow top. Well, coming home, both the positive and negative terminals popped off and the car died. I went back, reconnected them, and started to drive the car around, but I noticed that now, the car wouldnt even try to idle, if i let my foot off the gas, RPMs would just continue to drop till zero. Assuming it was because the car lost power while in motion, I disconnected the battery and EFI fuses for a few mins. This seemed to work, but the car still idled very low and now it was back to the original problem of idling and sometimes dying if I didnt slightly keep my foot on the gas. That night, I was out driving and noticed that if i hit the brakes, or even hit the window switches, my headlights and all interior lights would dim very low; the headlights almost seemed to blink when I hit the brakes. Well, i bought new connectors for the battery cables so they wouldnt pop off again, and the car hasn't fallen flat on it's face like it did before, but, when warmed up, it will idle very low (500-480) and sometimes, will falter and try to die. When revved up to about 1000 rpm, however everything electrical seems fine. Seemed to me like an alternator issue, but I just wanted to check it out to make sure it's not something else.
 

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I'm assuming you don't have a volt-gauge, otherwise you'd know within 2sec what was going on.

I wonder if autozone or whatever could hold a voltmeter onto the battery to check this out for you, but the gauge should display between 11 and 12 volts when the car is not running, and the second you start it, the alternator should kick it up to ~14.4volts.

If it is indeed your alternator that is dying (like mine did a couple of months ago), the car will do what you are describing and since it only drains the battery and doesn't recharge it, the car will leave you sitting one morning with a dead (drained) battery.

I got a refurbished alternator through ebay (~90$) as opposed to a new toyota one for $230. (this is a stock 90amp or whatever they are rated at). If you are heavily into car audio, be sure to pick up a stronger alternator then stock, or at least look into it. If you need the company i picked my alternator up from, let me know, and i'll dig it up for you.

Luke.
 

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Hijack....I believe I have an alternator problem. I just bought a multi meter.

What the car is doing. - Driving along and power begins to die, fuel pumps begin to sputter, car goes to a crawl then car dies, no power at all. Get a jump car will start drive for a little bit same problem....took 3 times to get home.(each try I took off like a bat out of hell to get the most distance per charge) Battery is pretty new and wouldn't just die while driving like that. so I assume alternator.

Well I have a meter so do I turn the to aux and test the terminals then start the car and test. 11-12 then started around 14?

How do I test the fus, since it isn't the typical open pull out kind. Is it true when those go bad its visual since it looks melted (hear say)

And to confirm becuase the Autozone kids couldn't. TT and N/A Alternators different? I have a spare one which I beleive is an SC300s and was tested good. But when they tried to match plugs apparent a MKIV N/A is different the an SC.

I'll do a how to w/ pics on changing if I have too.
 

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you know it's possible to get crank walk in an auto...

did you do any work on it recently? you couldve forgot a ground somewhere, but it sounds unlikely and definitely isn't it if your volts are low. +1, hit up autozone and get test the battery terminals. Volts as low as 13 are fine when its running, anything lower should be a red flag for the alt, especially if you start it up on 12 volts and it continues to go down. if you replace the alternator and get the same problem, could be the voltage regulator, among other things. I'd start with the alt and go from there
 

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I don't have an auto....or was the referenced to the OP?

I haven't tested the battery or current alt. in the car, only a spare SC one I had. I was asking the proper procedure in testing them while in the car with a multimeter.
 

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you know it's possible to get crank walk in an auto...

did you do any work on it recently? you couldve forgot a ground somewhere, but it sounds unlikely and definitely isn't it if your volts are low. +1, hit up autozone and get test the battery terminals. Volts as low as 13 are fine when its running, anything lower should be a red flag for the alt, especially if you start it up on 12 volts and it continues to go down. if you replace the alternator and get the same problem, could be the voltage regulator, among other things. I'd start with the alt and go from there

the voltage regulator is built into the alternator and would be brand new if a new alt. is installed





I don't have an auto....or was the referenced to the OP?

I haven't tested the battery or current alt. in the car, only a spare SC one I had. I was asking the proper procedure in testing them while in the car with a multimeter.


you dont need to be in the car to test the voltage. 1st thing you need to do is make sure your battery is fully charged (if not, throw a charger on it for a while befire testing) then go to the battery terminals under the hood, check voltage right on the actual battery terminals, not on the cars terminals. you should get between 12 and 13 volts (12.7 is the "exact" voltage a car battery puts out, but thats rarely the number you will get) if your battery is shot this will test much lower (you cant start most cars with less than 9 volts) this may test much lower if your battery has been drained as well, so make sure you charged it 1st.

now, start the car, go back under the hood and go back to the battery terminals. it should be anywehre from about 13.2 to 14.7 now. if its not in that range you have one more test, and its very difficult to pull off on some cars. while the car is still running, put your ground on the battery ground and your possitive goes directly on the alternator where the positive cable bolts to it. if your still not seeing 13-15 volts than your alt is bad. if you see 13-15 volts at the alt but only around 12 at the battery, you have bad battery cables.

p.s.
for the future, get yourself a voltage gauge, they are usefull for these kind of problems if hooked up properly, and also for keeping your motor in one piece, some electronic boost gauges will shut off if the voltage drops too low and you will chance a boost spike that will end your motor. same goes with many aftermarket electronics, stereos, fuel cut defenders, some snow kits, and so on... id rather see my voltage gauge dive than see smoke pooring out the hood any day.
 

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When I say in the car I mean with components still attached and not removed to be tested externaly. Not me physically inside the car.

The first voltage test should the car be in aux. or completely off?
 

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completely off for the 1st test. you want battery voltage with no draw on it at all

accassories, along with the ecu in todays cars can drop a battery down well under 11 volts, sometimes even less (increasing accessories and more powerfull computers are part of the reason for cars going to 24 volts now) thats basically why the accessory circuit was invented and why it shuts off when your cranking your car, the battery cant put out enough juice for the accessories and and starter to work at the same time
 

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Voltage at Battery with car off is 12.9, car on is 12.4. The alternator, of course, the only thing I haven't replaced yet.

Is there a good way to get at the 2 bottom boltsd to remove it? Or am I going underneath the car?
 

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^ Feel around with your hand to where the 2 bottom bolts are located. Once you find out, put the socket on a 4'' extension and loosen it.
 

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if you absolutly cant get under your car (too low for a jack and you have nothing to drive up onto to give you some extra room) you can take the fan blade or the whole fan and clutch assembly off your motor. they are each held on by 4 nuts. be careful taking the whole clutch assembly off, as the clutch tends to stick to the water pump and you risk bending the lip of the pully trying to get it off, not to mention you dont want to slip and take out your radiator while pulling and prying. but taking only the fan blades off of the clutch requires the fan shroud to be removed 1st, which is sometimes a pita, and you will see the nuts for the fan on the front side of the blades near the outside endge of the center circle

either way its a little extra work but makes it a lot easier to get to the alt bolts and get the alt up out if you cant get under the car
 
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