voltage/idle fluctuation (1 Viewer)

[Riad]

Need some help with this. I have been noticing this for a while now but never got around to adress it. Why does the idle go up and down when the turn signal is on? Only happens when I am waiting at a traffic light or simply waiting to turn (left/right). It is not that noticable but for me I guess it is. It feels like any time I turn on some thing electrical, the idle wants to go down. With the turn signals on the idle kinda has a rhythm, it changes with the signal's clicking. With the power wondows it some times goes below 500. Is it the alternator going bad? Or is there a voltage regulator that is acting up? The spark plugs are dirty needs replacement? What can cause this?

Any info is much appreciated.

 

[Rich]

When the turn signal lamp is on, it draws more current, which drops the system voltage. The voltage regulator compensates, resulting in the alternator outputting more current. In doing so, the alternator places a larger load on the engine. The idle rpms drop due to the increased load on the engine. When the turn signal lamp turns off, the required alternator output current drops, the load on the engine is reduced, the idle rpms increase.

 

[turbocruiser]

There are some similar threads out there, one of which was started by me wondering the same thing. Here are some conclusions I have worked with:

1. I dont know why that happens.

2. It used to happen before I changed my alternator brushes and it still happens after I changed my alternator brushes.

3. I dont know why that happens.

I've got a great brand new battery, perfectly functioning alternator, no wiring problems, no additional accessories like a fridge or inverter. Still with the turn signal on you can see and feel the rpms jumping just a hair up and a hair down in rythym with the signal. You can simulate the effect even slower by turning on the lights then off, etc. Anyways, did I mention that I dont know why that happens!?!

 

[Riad]

Thanks guys. I guess Rich pretty much explained how it happens. But does this mean one of these components are going bad? I don't have any extra load either. If I replace the voltage regulator and the alternator, is this going to stabilize? Just to compare, I did check the same thing on my wife's (2004) 4Runner. When I use the power window(s), the idle drops a hair but nothing with the turn signals. So I think, the 80s wires for the turn signals draw too much current. Or, all the stock wires (internal/external) are like that. Low voltage due to losses in the stock wiring reduces output and therefore idle drops/jumps. Maybe replacing the wires/wiring harness with better wires would suffice?

What do you think?

 

[cruiserman]

Voltage regulator.

 

[robjam]

We need pictures to really know for sure

 

[Riad]

Voltage regulator.

Is replacing the VR inside of the alternator is better than replacing the whole thing? I was thinking of getting the mean green. After all, the stock unit has taken lots of heat over the years. I will let ya'll know how it goes after I replace the alternator. I still think the OEM (elctrical) cables have something to do with it.

Oh well, thanks

 

[Rich]

You are replacing your alternator because the engine idle varies when the turn signal is on?

 

[Riad]

You are replacing your alternator because the engine idle varies when the turn signal is on?

Welp, that's what it sounds like I know, but unless I dig deep into this I can't say otherwise. I'm gonna hang on and see how bad it gets. If it is just the way it is now then I will just live with it. I also read the thread about the mean green alternator. So that's out of the question.

 

[Imagery]

I have noticed the same thing on mine too. It is even more pronounced after doing the side turn signal mod that Slee came up with ( adding an additional lamp in the front turn sig housing, connected to the turn sig circuit) and also running the indicator lamps in the ARB bumper. I watch mine on the volt meter in the dash as it drops probably 2 volts or two needle widths as the blinkers are on. Even moreso with the hazzards running and I really notice the enging idle changing with the addition of the A/C running on high. I notice that when I come to a stop light, with the A/C on high, as soon as I take my foot off the gas and apply the brakes, the A/C blower slows down noticebly. My idle rpm sits at about 900 and as soon as I apply the accelerator and the rpm reaches about 1200, everything electrically comes back up to about 14.5. I know it has to do with the altinator output being actuated by engine speed so it does not really concern me but it sometimes bothers me. I do have the 200 Amp Mean Green installed and we bench tested it to find that it actually outputs about 175-180 which is plenty. If you run a volt meter say from your cig lighter and just watch the voltage at that point, you will see it drop when certain things are actuated, but while your rpm's are above the point which kicks in the altinator, you will see very little if any voltage drop. I also run my headlamps upgraded to 65w/100w Hellas and up until last week when I finally installed Slee's upgrade harness, I got about 1.5 volt drop with high beams and with driving lamp Hellas on even more drop. Now, since with Slees harness, it connects the headlamps and aux lamps directly to the battery through 30amp rellays so it does not effect the eletrical system at all. Perhaps something like that could be done with the turn indicatior lamps. Try measuring your voltage at idle first at the altinator output and then see how much drop you get at the lamps. You will need a fast acting digital volt meter or a good analog to be able to get a good reading on the turn indicator lamps. I think they say that anything more than about .5 volt drop would be considered to much and increasing wire gauge would be necessary. Anyway, give that a try and see what you find. Good luck and let us know what you end up doing.

 

[Riad]

I appreciate the info Imagery . Yeah I need to get a digital volt meter to get an acurate read. I have this old fashioned analog one that shows about a hair more than 0.5 drop with the turn signals, head lights (low), heater and breaks on. Would you be able to tell me what gauge wires are in the Slee harness?

Thanks

 

[Imagery]

I am not exactly sure of the guage but I believe they are one or two ga up from stock. If stock wires are 14ga then S;ee's is like 12ga I think. I'll look to make sure but the thing that it does is use shorter lengths from the battery to the lamps instead of traveling through the stock harness. Not much shorter actually but enough that with just a small increase in wire size is more than ample. Call them at Slee's and ask what they might suggest about upgrading the turn indicator harness. Might be more difficult since you have the rear lamps to deal with as well but you might be able to just start with the fronts to see if it helps. But look at the voltage guage in the dash and see if it bounces with the flashers at idle and then see what it does after applying accellerator bringing rpm's up above 1000. Your altinator should kick in and reduce that effect. You can go to Radio Shack and get one of their 12volt meter and temp combos that plugs into the cig lighter and you can monitor your actual voltages there while you drive.

 

[dfmorse]

Riad;

Due to the FJ80's poor grounding scheme, the problems u are encountering are fairly normal.

I am assuming that your battery is not over 4 years old and the terminal connections are clean and tight.

One of the over looked secrets is the ~10 gauge black wire from the negative battery terminal to the left-inside fender. This connection to the fender is one of the primary grounds for the lighting system throughout the vehicle. I will bet that this connection is corroded.

What this does is increase the voltage drop; causing the alternator increase its output. Clean this connection and any other ground connections that u can find and see if this reduces the symptoms.

I have had similar problems like yours and cleaning up the grounding has reduced rpm fluctuations to a minimum.

...

Also check the firewall ground strap at the rear of engine..

...

 

[Riad]

My battery is a yellow top, replaced couple months ago. The grounding scheme never crossed my mind. I will give them a shot. First I need to stop by at Radioshack.

Thank you very much .

 

[Biff]

I've got the same thing on mine when I use anything electrical, I've done the following things and still haven't resolved it:

1. Replaced alternator brushes
2. Didn't work so I replaced the whole alternator
3. Didn't work so I replaced battery and battery cables
4. Still didn't work so I replaced the alternator cables

only thing I haven't done is replaced the VR, if I'm lucky that should be it.

 

[Riad]

OK, I am cutfused, are there two VRs? I thought there's a VR inside the alternator. Where's the other one?

 

[Biff]

I have no idea where the VR is, if its inside the alternator then I have changed it. Somebody that knows more than me please confirm where the vr is.

 

[BillyGoatMTB]

*Bump*

Evening MUD

Did you ever find a solution?