Collecting Dust...

So, my Power Probe IV has been spending an awful lot of time in my tool box. Ever since I got my 15ft retractable test leads, I go for my test light or meter instead.

There's been a couple of instances when checking for voltage with the Power Probe that I've been mislead into believing that there was good power when infact there was not.
I was begining to not trust it very much anymore, hence the extended vacation to the bottom drawer of the tool box!

I started thinking that was maybe my fault for not using the tool correctly, so I decided to do some playing around with it this evening after work.

The car in my bay has a weak battery, so keep that in mind when looking at the voltages

So for the test I had in mind I need my Power Probe, my modified incandescent test light and a multi meter.

First up, I demonstrate where the Power Probe has let me down in the past by connecting my test light to battery positive and measuring the voltage at the tip of the light with the Power Probe:
We all know by now that no current flow=no voltage drop, so the PP4 displays source voltage, lights the red led and makes the high pitched tone that indicates good power.
That's with nearly 10 ohms resistance in the "feed wire" in the form of a cold test light bulb.

But... There are a lot of modes of operation for this tool, so let's perform the same test using "Feed Test" mode:


Well look at that! Now the circuit "resistance" is evident.
A quick rationality check with the meter shows that the PP4 measurement is pretty accurate:

I don't know how useful it will be with lower resistance issues, but I'm going to give this tool another chance.

I have not felt the need to upgrade to the PP4, but I love my PP3. I use it everyday. It is my first grab for doing initial testing.


Edit:

I've been mislead into believing that there was good power when infact there was not.

I think it would be nice if they added something like the :whistle: Load Pro :whistle:

Haha I love it everyone needs a load pro!

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pole71 wrote: I think it would be nice if they added something like the :whistle: Load Pro :whistle:

That's where I'm hoping the "Feed Test" mode will pick up the slack. It's kind of like an instant volt drop test.

The screen displays source voltage, tip voltage and circuit resistance at the same time.

So how does it calculate the "tip voltage" compared to "battery voltage"?
Does the PP4 load the circuit in feed test mode?
Or is tip voltage a calculated value based on a resistance measurement?
Or is the resistance value calculated based on current from the hypothesized load?

I guess I could set up the same test through the amp meter and find out...

Test light connected to battery positive, PP4 in Feed Test mode run through amp meter:
You can see a live reading of 15ma with a max 22ma. Test light is not lit.
So I believe the PP4 must be loading the circuit in Feed Test mode.
To see if it is also behaving as an ohm meter, i decided to do a voltage check between the negative lead of the PP4 and the probe tip:


Displayed on a graph and in digital format to show activity and min-max levels.

I went back and Re-read you original post. I think I understand, now. The FEED TEST shows the RESISTANCE that causes the voltage drop, rather than the voltage drop, itself?

I bushed the dust off my Load Pro and did the same test.

pole71 wrote: I went back and Re-read you original post. I think I understand, now. The FEED TEST shows the RESISTANCE that causes the voltage drop, rather than the voltage drop, itself?

I bushed the dust off my Load Pro and did the same test.

Exactly

I did the same with the Load-Pro, and just like your test light, mine lit as well.

I stopped using that tool just for that reason! I accidently started a Saab that came in as a no crank while checking the ignition switch with my Load-Pro.
It was a complete surprise, someone could have been injured.
That, and I had it on my Verus, went check my ground by probing B+, and a spark arched from the tip of the Load-Pro to the positive battery terminal before I made contact with the terminal! I was not even pressing the button.
Again, complete surprise and potentially dangerous scenario!

I may use it to check computer power and grounds, but it's not my every day test lead any more...

Off subject, I also figured I'd check the ohm meter output of the Vantage while I had everything out since I fixed my parts Vantage while I had some vacation time last week:

"Hey Noah, that thing comes with a user's manual!"

I just watched Eric O's Tool-time on the Power Probe IV. I'm, now, thinking this could really come in handy. I love my Vantage Ultra, but this would be a much easier Quick-Check tool. I see the price has come down, since it's release, too. :huh: I guess, I'll add it to my "Gonna Get" list.

I've been eyeing one of these for awhile, too. It was actually Noah that really got me excited for one of these, surprisingly. :silly: He did a thread awhile back about diagnosing a no start from start to finish with nothing but the PP4. Cool stuff.

My biggest problem is my PP3. :lol: It just refuses to die. If it'd just break, I'd have a lot less problem with replacing it. But it still does it's job.

Tyler wrote: I've been eyeing one of these for awhile, too. It was actually Noah that really got me excited for one of these, surprisingly. :silly: He did a thread awhile back about diagnosing a no start from start to finish with nothing but the PP4. Cool stuff.

My biggest problem is my PP3. :lol: It just refuses to die. If it'd just break, I'd have a lot less problem with replacing it. But it still does it's job.

You remember that?

It's got a pretty cool injector driver test that shows source voltage, injector on time, ground voltage and inductive kick.

So i figured those are all the points i want to see in an ignition coil, so why not try it on a cop?

Ummm, because the screen goes black when you do that. :blush: :blink:

The abbreviation "ind kv" stands for inductive kick voltage. It is not actually capable of measuring kV...