I just picked up a digital multimeter this past week, so I'm beginning to compile a list of sensors and whatnot that I can begin testing to diagnose my high cold-idle.

A new issue that I have not ever read about or since others experiencing, however, is a drop in idle when flipping on my headlights. Any thoughts? Have searched and am still searching.

'93 4runner - 22re/5speed

 

Have you checked your ground wires under the hood, alternator, and battery?

 

i'd be curious to know the charging voltages, with the lights off and with them on.

 

Lights put a lot of draw on your electrical system. When you turn on your head lights there are quite a few other lights that also come on such as your tail light, liscense plate light, parking lights, dash lights, center console lights ect.

The stock alternator is only55-60Amps on a good day so turning on ALL these lights at once is quite a load. Its not uncommon on the older trucks and 4runners to have the volt meter flick with the turnsignals with the heads lights on also.

Best thing (other that new thicker power wires) is to install LED light bulbs in all locations possible.

 

thats normal. Added electrical drain so the alternator has to work harder, more resistance to spin the alternator to supply such power, belt driven off the crank so the crank spins a bit slower. Thats why we get worse fuel economy at night, and when the stereo is cranked.

 

Check your idle speed is properly adjusted. At the factory idle speeds it shouldn't bog the engine down. if the idle speed is w/in spec it could indicate a problem.

Inspect the wires and connections like others have mentioned, clean and firm insulation not cracked ect.

Do the charging system inspections

 

I have seen this happen all the time.

most often a electrical issue .

neglected battery terminals just worn out battery cables on the 22r series engines the wire coming off the alternator just gets cooked being below the exhaust manifold.

As the electrical system degrades the ability to carry a load goes down.

another problem is going cheap on batteries because of the low alternator output( compared to most) plus all the added electrical load add low end battery and neglected charging system

I have had some so bad add another electrical load the engine just quits

 

Interesting. You all have commented notions that are inline with things I have been reading. I've been testing a couple things this weekend, but I am going to go back and retest them when A) It isn't raining out, and B) I have learned this new digital multimeter a little better! In terms of draw, I guess I noticed similar idiosyncrasies with my '88, I guess I never noticed it WHILE dealing with tracking down a more stated idle issue such as I am now.

As, it becomes more apparent WHY individuals swap their alternator to a larger output, as well as why so many people stress being able to locate your ground-locations (so can both make sure of clean contact AND know where larger ga. wires can go.)

Battery is kinda cruddy looking, I'm going to do a little baking soda cleanup on the terminals tonight when I put it back in (it's currently in the cargo area - I've been trying to diagnose rear window trouble! Ripped the door apart and opened up the motor to find it had rusted itself nice and tight on the inside. More on that elsewhere), and I plan on looking at the electrical schematic to find accessible ground points to ensure clean/sturdy connections.

I don't foresee myself ever having a winch or OBA or a fridge (items with a lot of draw) but I wonder if I would ever desire to upgrade the alternator?

- babyfood1217

 

I still run the stock alternator but with all the major circuits upgraded to new and heavier then stock size cables and wire

I also run the highest output Interstate battery in the normal case size.

I have no problems only do the odd recovery work with the engine running.

 

Could be bad battery connections or your battery is not very good. Alternator is taking all the load.