4Crawler

iTrader: (3)

Well, the starter solenoid only gets power in the "START" position of the key, so that is where you need to do the test at. The idea is to measure the voltage "under load", since it is the voltage drop due to the high current flowing through the wiring that is what you are trying to find. So you can either have a helper turn the key while you look at the volt meter in the passenger side wheel well. Or you can extend a wire from the solenoid to the passenger compartment and set the meter beside you and check the voltage each time you start.

91Toyota

So basically I can't test this with a digital voltmeter because it would move to fast to get an accurate reading?

It seems weird for me to be sitting under my truck when my girlfriend starts it so I can quickly read the voltmeter. Maybe it would be better to remove the coil wire?

I think what I'm going to do is extend the wire all the way to the window and so I can glance at it. Might even add some duct tape too

4Crawler

iTrader: (3)

Digital meter is fine, you just want a reading while the engine is cranking over. That is likely a few seconds.

Don't need to be under the truck, just have the meter hooked up to the starter and hang it out the passenger side wheel well.

Yes, this way you can keep an eye on it, especially for that intermittent problem.

91Toyota

Ok, tested it while cranking and got ~9 volts.

Also, i wanted to see if I was getting power to the hot wire on the starter while sitting there and there was none...is that right? I put the positive touching the terminal on the starter and the ground on the frame and it shows nothing.

Battery voltage...


Starter solenoid voltage while cranking

chubbydude

If you want to test the voltage to the solenoid, it is probably best to disconnect the solenoid wire and then test it when you turn the key, that way the starter will not crank.

I would personally do the starter relay fix regardless, since voltage drops give such intermittent starting and it is normal as vehicles age. I did have a relay go bad on me, but at least I knew what the problem was.

The hot wire on the starter is direct from the battery, so you should get something if the battery and grounds are hooked up.

4Crawler

iTrader: (3)

Correct, there should be no voltage at the solenoid when not starting. The 9 volts sounds a bit low, but to double check, you can either measure the battery voltage (while cranking the starter) or put the meter probes on the solenoid terminal and the battery "+" post (to measure the drop between those two points). If the battery is dropping to like 9 volts, that may point to a weak battery or bad battery cables/clamps.

91Toyota

Yes, there is no voltage to the solenoid OR the cable from the battery to the starter.

I will have to make a video in order to hold the probes to the battery and turn the key.

Results will be in a couple minutes.

91Toyota

Starter relay fix? Truck has a starter relay. I tested it with a 9v battery, hooked up the (+) to one terminal and the (-) to the other and it clicked. I did it a bunch of times and it clicks just fine. Nothing else makes a noise or anything.

snobdds

I think your in the same boat as me. My battery is the problem. Although it is not dead, it is just no longer providing enough current to engage the solenoid.

My battery is reading 11.9 and when I test the solenoid it goes to 10.1. If I am understanding this correctly my solenoid should be right around 11.9 +- .05.

So I am off tonight to buy a new battery!

91Toyota

Ok, well it looks like my truck jumps down to around 10.5v while cranking. Not sure how normal that is. I'm thinking I might replace the + side battery cable.

http://s848.photobucket.com/albums/a...nt=12-1-09.flv

91Toyota

I would gladly buy a new battery, no problem! Its a 3yo battery...i figured batteries that were taken care of should last between 5-7 years (or so I was told).

Video added^

snobdds

Well Mine is pushing 6 so I think it's time for a new one.

4Crawler

iTrader: (3)

11.9 at the battery is fairly normal while starting, the starter pulls a boat load of current (several hundred amps). But the solenoid should be within 0.5 (1/2) volt of that, so 11.9 - 0.5 is 11.4. Since you show 10.1 at the solenoid, sounds line a wiring issue:
- http://www.4crawler.com/4x4/CheapTri...l#OtherOptions

91Toyota

Let me some this all up.

- Solenoid has 9v when cranking
- Battery has 12.4v sitting and 10.6v cranking
- Relay "clicks" when power supplied

91Toyota

So, should I cut relay 4th pin wire and add the wire + fuse?

Oh my bad, you were talking to him. lol.

4Crawler

iTrader: (3)

Sounds a little low, depends on the battery charge and temperature. But to check the cables, put the volt meter probes on the battery terminal and the other end of the cable you want to test and hit the starter. The voltage drop across that cable will be what the meter measures. Would imagine anything over 0.1 volts would not be all that good.

91Toyota

Ok I will give that a try soon. Wouldn't that be the same as testing the continuity?

Anyway, I appreciate your help!

91Toyota

Ok, just tested it. Put the negative probe on the + battery terminal and put the postive probe on the starter wire from the battery and it showed 0.26 on the voltmeter.

So, whats next?

4Crawler

iTrader: (3)

Similar but continuity (or resistance) just uses a tiny (micro-amp) current to test, Slamming 200 amps or so through a cable will multiply the effect of any tiny resistance. Most ohm meters have trouble reading down below 1 ohm of resistance, you need to invest in a big buck tool to measure tiny resistances. But with 200 amps times some tiny resistance = a measurable voltage. In your case, 0.26 volts equates to .26/200 or about 1.3 milli-ohms. You could look up the gauge of wire and length on a wire chart and see if that is a reasonable resistance and if not replace the cable:
- http://www.interfacebus.com/Copper_Wire_AWG_SIze.html

4Crawler

iTrader: (3)

Shows a 1.6 volt drop to the solenoid from the battery, that is >more than the 0.5 volt drop the FSM shows. Find out where that voltage drop is coming from.


Indicates the relay coil (assume you are referring to the starter relay) is not burned out.