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Discussion Starter #1
My alternator has slowly been dying in my '97 4DR FWD, but it has been polite enough to stay functional long enough that replacing it is optional with money from this years tax return, rather than a critical repair on my daily commuter. The battery slowly drains and every 3-4 weeks I throw it on the charger for a few hours once I start noticing a slight sluggishness at start up.

Trying to decide if going to a 90 amp alternator instead of an 80 amp is worth the slight bit of extra money (~$20 or so)? I am planning to add some extra circuits to power extra USB and 12V outlets, but not adding any really heavy load equipment (no thumping stereos in my vehicles, thank you very much).

Still trying to decide if I am going to do this myself in my very limited free time, or if I will take it over to the local VoTech school to have their students replace it at the cost of parts and $15 per hour shop time.

I love this little truck, I've had it almost a year and the faults are minor inconveniences so far, I have at least 1 door switch that always registers as door closed, and at least 1 more switch that shows always open, if I end up having to replace 4 of the 5 switches (front passenger is known good) it will probably run more than replacing the alternator looks like it will run.

I keep the tires inflated at around 38 PSI, gives the stiffer ride I like and I am getting around 25 MPG (calculated at each total filling, consistently between the low 24's and mid 26's, much of the driving at 60MPH +). My girlfriend grumbles about this, her truck only gets around 12-13 MPG, a Dodge 2500 super duty 4x with a big diesel, usually towing her mobile dog grooming trailer.

Rob Lewis in Sunny Arizona (if I could I would gladly trade a few hours of cold and cloudy weather for several weeks of our sunny and highs in the mid-upper 80's weather).
 

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Its really easy to change. I think just two mounting screws and the tensioner screw. The ele trical connections are easy to get to also. Just remember to disconect for battery first.
 

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Suggest that before spending money both the alternator and battery be tested - many auto parts supplier stores will do that at no cost. The problem may lie elsewhere, for example in the regulator system.
 

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Suggest that before spending money both the alternator and battery be tested - many auto parts supplier stores will do that at no cost. The problem may lie elsewhere, for example in the regulator system.
Put a voltmeter across the battery terminals.
With the engine off a good battery should be 12.7 volts

With the engine running it should be around 14 volts if the alternator is good.

13-14 volts if the alternator is marginal, but still charging.

No increase in voltage withe the engine running means the alternator isn't charging at all.

I'm pretty bad at electrical stuff but at this point I inspect the wiring and check fuses, and if they are ok usually replace the alternator.

I'm sure there are some more steps you can take without too much trouble to further isolate the issue, such as checking voltage directly off the alternator, but I don't have the specifics to tell you.
 

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I just replaced the alternator on Zepheretta (2005) and the serpentine belt at the same time. It's a pretty easy job to do yourself. Look on the 4.2 DIY area for my step-by-step procedure or search "alternator" for some tips. Ours started with a HOWL from under the hood (bonnet) that turned out to be the alternator (easy) rather than the water pump (PITA). You don't have to replace the belt but I was not sure how long it had been on the car and while I was doing things.....:)
 

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Discussion Starter #6
I have tested both the battery and the alternator a couple of times in the year I have had L'il Beep Beep ( I have no idea where that name came to me from, but it just feels like the right name for that fun trucklet), the battery shows around 12.7 volts after being on the charger overnight, and then driven to and from work the following day. With the engine running, there is very little increase in the voltage, so I am getting some slight charging from the alternator, but I am getting the classic symptom of the headlights dimming when I raise or lower the windows at night.

I have the new alternator on order now, when it arrives I will check what condition the belt is in, and replace that if necessary while the alternator is being replaced. I went with the 90 amp, I would have had to wait until Friday to order the 80 amp because it had a $75 core deposit in addition to the cost, the 90 amp is a new alternator, not a rebuilt. I know that $75 is a deposit, and refundable once the old core is sent in, but this way I should have the alternator in time to decide if I am going to change it myself this weekend or take it to the VoTech next week.

From perusing the archives, the 3 big tricks with replacing the alternator seem to be:
1) disconnect the battery
2 hit the bolts with a penetrating oil and then rap them firmly to break whatever bond may have formed in the threads
3) the battery really is disconnected, isn't it? double or even triple check that.


Rob in sunny Az.
 

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OK: you are about to find out how easy it is! Please read my post on the 4.2 forum for suggestions about changing the belt as well. Toyota's have the intelligent "self-tensioning" belt but that tension is maintained by a hydraulic cylinder attached to an idler pulley. I'm sure you have checked the bent tension to make sure the tensioner is OK. When demands are put on the alternator, it causes more drag and causes the belt to slip when under a load if not tight enough. (The mechanism in the LifeCyle stationary bikes for making it harder to pedal: an alternator!):)

I have fond memories of driving home in my younger days in a Celica in the dark with a "failing" alternator, finally driving behind a car that HAD lights. He, thankfully, understood what was happening and drove us into town! It was a slipping belt, not the alternator itself. Adventures..!:D:
 

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Oh, yeah: make sure the battery is disconnected.....:D
 

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Discussion Starter #9
New alternator arrived yesterday, just need to pick up some penetrating oil, anti-seizing compound, and a torque wrench.

Rob in overcast Arizona (really wishing I did not have to stay at my desk today, it is wonderful out right now)
 

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Is there anything else I should be doing when I replace the alternator? I have already done 2 of the big 3 (battery ground, left side of engine block ground) so I will at least add the alternator to battery, may add the right side of engine block to frame, I don't see much benefit to doing more than that.

Rob in still overcast Arizona (Hurrah, 2 cloudy days in a row).
 

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Discussion Starter #11
And I will also look at the serpentine belt condition while I am in there.
 

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How did it go? Have you changed it yet? I forgot the 4.1 series has a tensioner for the belt you have to adjust yourself but is an intelligent device with a screw bolt to get the tension just right without something that will slip back as you tighten the bolt. If you don't know how long the belt has been there, you might as well replace it while you have the place apart.....and you're at the parts store.... (Did you disconnect the battery....:wink:)
 

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Discussion Starter #13
Picked up a sinus infection late last week, coughing made it too challenging to even try. But the weather should still be great next weekend. There is an auto parts store about a 10 minute walk from my house in case I need any other parts. hopefully I can take care of it this weekend, but I have a new computer to set up at home, and I need to replace at least 1 old 2 prong outlet with a 3 prong self grounding outlet before I can start that, while I have that circuit disconnected, I may as well to the other 2 prong outlets in that room,
 

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Discussion Starter #15
Finally got my lazy butt around to replacing the alternator, a few issues cropped up, enough to extend it to about 4 hours of work.
1). My hands are a little too big for doing this work quickly in the tight spaces.
2). My hands are a little too shaky for doing this quickly (kept having the socket slip off the rear bolt and/or knocking the socket off the ratchet wrench)
3). I need to put together a better assortment of tools for working on L'il Beep Beep.
4). I just need to do a lot more shade tree mechanic projects to get my confidence levels and know how up.

Only 2 serious issues I ran into:
1). Spacing was off on the bolt holes, solved by my girlfriends neighbor who happens to be a heavy equipment mechanic and former car auction mechanic, he apologized for leaving his big pry bar at work, so he had to settle for his 3' harbor freight pry bar to shift the bracket for the forward, tensioning bolt into line with the threaded hole on the alternator.
2). The long bolt/threaded rod for adjusting the tension is missing (any idea on the specs for replacing this?) and I need to adjust the tension a little bit.

While I was unbolting the splash plate under the engine to get tools I dropped anyway, I went ahead and put larger washers to secure the plastic around the threaded holes from pulling away from the frame of the trucklet.
 
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