Mechanics

/91 MPV ALTERNATOR WARNING

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My family owns a 1990/1991 MPV that all of a sudden would not start this morning. The alternator warning light came on, and being new to car repair as a teenager driver, I'd like to know what could be wrong, as the manual isn't very descriptive.
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MaxHuang
April 20, 2007.




Check the alternator belt whether its still there or could be slipping.

Go to radio shack get a cheap multimeter-put it in DC scale 20v position-measure the battery voltage it should read 12.4volts or better, now start engine if it reads 13.5-14.5 the alternator is fine. Check all connections and report back your findings. We might have to go deep6 on this as a beginner

Tiny
Rasmataz
Apr 21, 2007.
I checked the alternator belt this morning after I woke up, and it looked to be in pretty good condition still. I have yet to try jump-starting the van, but that's next on my list before possibly getting a mechanic to look at it. I'll see if I can get what you're referring to from radio shack.
EDIT: Forgot to add, but when I turn my key in the ignition, I have power, as in the sound system and lights work, but the engine doesn't even make an attempt at starting. No sounds or anything at all.

Tiny
MaxHuang
Apr 21, 2007.
Either power is not getting to the starter or starter itself

Possible problems: Ignition switch, neutral safety/inhibitor switch, wiring problem, and starter itself
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Tiny
Rasmataz
Apr 21, 2007.
So are there any none-mechanic solutions? Maybe something I can simply do at home?

Tiny
MaxHuang
Apr 21, 2007.
Do this get a partner to crank over the engine while you bang on the starter with a 2x4 wood.

If there's power reaching the starter from the ignition switch-drop the starter and pull a CSI on it. Or a new one. Make sure you have good contact on the battery terminal at the starter all the way to the battery to include the negative.

Tiny
Rasmataz
Apr 21, 2007.
As well, check the width of the belt, and it should be a tad over 1/2 in.
If the belt is narrower than this, the alternator won't give proper voltage at idle.
And, you can tighten it but it still will slip.

Tiny
Hippo800
Aug 5, 2007.
The 3 terminals on the mazda alternator are for field, stator, and battery.
When the light goes out on the dash, that indicates a parity of battery alternator voltage.
But, the battery could still be undercharged via. A slipping belt, worn alternator, etc.
The only correct way to determine the battery/alternator relationship is with a voltmeter set at 20 vdc.
The voltage of the battery before starting the engine should be @ 12.80 volts.
!2.8 volts indicates a fully charged battery.
When you start the engine, the voltage should be 14.5 at the battery posts.
This voltage will fluctuate if headlights are turned on, etc.
But, after shutting off the engine, the battery voltage should climb back to @ 12.8 to 13.0 volts.
If you don't fix the front rear-view mirror dome light, this could be a potential electrical short, you know.
Buying a new one is not the answer because the plastic light bulb terminal holder is plain garbage.
It has to be fixed using a new UHMW plastic terminal bridge and the original terminals, with brass screws. 3/32 in.
I have done this myself and don't expect problems for 20.5 yrs.
Also, lubricate the ball bearing at the rear of the starter armature with NLGI 2 grease, and the starter gears.
Lucas Red' N tacky should be ok, but there are better greases from 76 Lubricants, such as Unoba NLGI 2.

Tiny
Hippo800
Aug 9, 2007.

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