Stalling / won't idle - electrical problem?

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Teddy1
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Joined: Mon Jan 12, 2015 10:26 am

Post by Teddy1 »

Teddy1
Advanced Member
Posts: 75
Joined: Mon Jan 12, 2015 10:26 am

Post by Teddy1 »

Jerry,

I don't mean to "oversimplify" this, but upon FORCING my car to develop your car's symptoms, here's my "digital" troubleshooting for you:

Situation A: If your car has both of those idiot lights on ALL THE TIME (whenever the car is running), then you have a bad alternator or faulty regulator or rectifier (both of which are integrated inside the alternator in 95% of the Tercels) or it is a bad ground NEAR the battery... like, literally, within the first 10 inches of the Negative battery cable, or, a burned fusible link, a major short in the wiring harness or the ignition spark module is arcing (internally), and therefore about to die.

Situation B: If your car lights up both of those idiot lights ONLY when the RPMs drop below 600, you have a vaccum leak.

Now then, if you want a quick way to rule out a "short" in the wiring harness, use a multimeter between the battery and the car...

Let me illustrate: Remove the positive cable from the battery. Set your multimeter to "amperage, DC" measuring mode... put one of the multimeter probes on the positive battery terminal, and one on the disconnected cable (thereby connecting the battery VIA or "through" the multimeter).

With the ignition key switched off, and no accessories (stereo, headlights) on, you should see less than half an amp AT THE MOST.

If you see several amps flowing through the multimeter when NOTHING is turned on (to include the ignition switch) then you have a short.

If no short is detected, try this EXACTLY the same way, but with the ignition key in the "on" position (but DONT start the car). After 2 seconds or so, the surge amperage will drop back down (as soon as the ignition coil is charged and the spark ignitor is vibrating)... if you note more than 2-3 amps with the ignition switch in the "on" position, you have a short in the switch itself, in the alternator or your ignition spark module.

If the ignition spark module is suspected, the simple voltage and resistance tests specified in the shop manual will easily determine if it's bad.

Did that help?
Jerry
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Joined: Tue Dec 14, 2004 3:13 pm
Location: Bakersfield, CA USA

Post by Jerry »

takza and Teddy:

I so owe you both a beer if you're ever out this way - thank you so much for your help.

I haven't read everthing yet, but will do so, and will examine the photos as well. Also got out my Bentley that has a thorough electrical diagram (even distinguishes between the regular and SR5 models, and those with the 55 and 50 amp alternators), and hopefull will be able to come up with a solution.

Thank you again,

Jerry
Jerry
Bakersfield, CA
Owner of a rusty '84 Terc SR5 4WD
251,000+ miles, original engine, second transmission.

Transmission soon to GRENADE!
Jerry
Advanced Member
Posts: 62
Joined: Tue Dec 14, 2004 3:13 pm
Location: Bakersfield, CA USA

Post by Jerry »

Teddy:

So, if I am interpreting those pictures correctly: As you're looking at the alternator from the top, the terminal on the left has nothing else attached to it, aside from the condensor (the little capacitor looking deal) hooked to it, correct?

BTW, if your engine bay is any indication... Your car is gorgeous compared to mine! :)

Thank you again,

Jerry
Jerry
Bakersfield, CA
Owner of a rusty '84 Terc SR5 4WD
251,000+ miles, original engine, second transmission.

Transmission soon to GRENADE!
hornett22
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Posts: 207
Joined: Sun Dec 12, 2004 6:42 pm
Location: glastonbury connecticut

Post by hornett22 »

toyota alternators get a buildup of brush dust inside.this mixed with oil from a leak is bad news.also the brushes will wear groves in the rotor shaft and the brushes will be over extended.i have seen many reman alts where they never replaced or repaired the rotor shaft. try to stick with napa ,carquest or factory alts.the discount chains sell junk. i have also had good luck from local rebuild shops.
there is only one jeep.and that is one too many!
takza
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Posts: 4414
Joined: Fri Apr 02, 2004 4:28 am
Location: Tibetan plateau

Post by takza »

Jerry wrote:
Looking in the fuse box under the hood, I noticed the engine one was blown. So, I replace with another 15 amp fuse, restart the engine, revving it up a little bit. When the engine dies I shut off the ignition and check the fuse - the new one has blown as well.
Someone had the blown engine fuse problem before on this list and I think they solved it....took them awhile...might be able to look back under any HEADINGS involving fuse...starting...alt problems and find it.....

You might want to have your new alt tested...since if you don't replace them as a pair...one can trash the other at times?
Give a boy a gun-give a biatch a cell phone-and pretty soon you almost got yourself a police state.

Orwell said: War is peace! Freedom is slavery. Ignorance is strength...

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Jerry
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Posts: 62
Joined: Tue Dec 14, 2004 3:13 pm
Location: Bakersfield, CA USA

Post by Jerry »

Good news - lmy car is alive again. :)

The problem must have been either a bad ground, or a bad positive connection to the starter.

I ended up tighening the positive cable to the starter, as it was loose.

I also removed, cleaned, and checked the resistance of the ground cable "under" the car (goes to one of the bolts that connect the engine to the trans). It was oily (I have a decent oil leak). Cable was good and connections didn't look too bad, but cleaned 'em and put it back.

The negative battery cable was also loose at the engine. Tigtened it up good. There is also a ground on the very "front", next to the radiator shroud. (10mm bolt). The OEM battery cable had been previously replaced with an aftermarket one, with a crimp connector going from it to the black / yellow wire that led to ground. I cut the connector off, and saw some corrosion. Got out the propane torch, cleaned the wires and made a good connection, and soldered them together, wrapping with electrical tape. (I didn't have any shrink tubing handy...)

Double checked to make sure the battery posts and connections were clean - they were. Pulled the green plug from the back of the alternator and was going to test the voltage to the terminals on the plug. Put a fresh 15amp fuse in the "engine" spot, started the car - voltage still at 12.2 volts, but fuse did not blow. Feeling kind of stupid, I turned off the car and plugged the green connector back into the alt. Started it up - 15amp engine fuse did not blow, and had charging voltage (about 14.3 volts) at the battery. Life is good.

Can't thank you guys enough for your help on this one. It kinda sucks to have had spent $$ on an alternator and a regulator (looks like I have an extra regulator now, the alternator I have to turn in as a core), at least I now have some (hopefully) more reliable parts in the car, and am good for another 236,000 miles..

I am guessing it was one of the grounds - go figure, you learn something new every day.

Jerry
Jerry
Bakersfield, CA
Owner of a rusty '84 Terc SR5 4WD
251,000+ miles, original engine, second transmission.

Transmission soon to GRENADE!
Teddy1
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Posts: 75
Joined: Mon Jan 12, 2015 10:26 am

Post by Teddy1 »

Right on, Jerry! :)
hornett22
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Joined: Sun Dec 12, 2004 6:42 pm
Location: glastonbury connecticut

Post by hornett22 »

amazing how many times it is something so simple and you overlook it.happens to the best of us.
there is only one jeep.and that is one too many!
yppg
Newbie
Posts: 7
Joined: Wed Oct 20, 2010 4:22 pm
My tercel:: 1987 4wd wagon originally automatic modified to 6 speed
Location: virginia

Re: Stalling / won't idle - electrical problem?

Post by yppg »

lots of good info. in this thread. My charge, temperature and brake light came on when I stopped at a light last night. The dash lights seem noticably more dim and the alternator is making a rough sound when the engine is running, so I am hoping I have a clear-cut case. No running or braking problems. Will post outcome.
yppg
Newbie
Posts: 7
Joined: Wed Oct 20, 2010 4:22 pm
My tercel:: 1987 4wd wagon originally automatic modified to 6 speed
Location: virginia

Re: Stalling / won't idle - electrical problem?

Post by yppg »

yes, temp. charge and brake lights on meant alternator was bad.
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