97 Boxster with Intermittent Brown Out

[JFP in PA]

Yes, the primary ones are the large diameter cables. Maximum allowable voltage drop would be about half a volt. Because cable lengths vary from vehicle to vehicle, and their original starting internal resistance is unknown, voltage drop is quicker and more accurate. If you have access to a Power Probe electrical diagnostic tool, it has a built in voltage drop capability.

[Bush Pilot]

Originally Posted by JFP in PA

Yes, the primary ones are the large diameter cables. Maximum allowable voltage drop would be about half a volt. Because cable lengths vary from vehicle to vehicle, and their original starting internal resistance is unknown, voltage drop is quicker and more accurate. If you have access to a Power Probe electrical diagnostic tool, it has a built in voltage drop capability.

I can simply make a voltage measurement across the cable with one lead at the battery + and the other at the block where the alternator and starter tie in, located towards the front top of the engine. I don't see this potential fault causing an intermitten issue like I'm seeing though. But it's an easy measurement.

[JFP in PA]

Originally Posted by Bush Pilot

I can simply make a voltage measurement across the cable with one lead at the battery + and the other at the block where the alternator and starter tie in, located towards the front top of the engine. I don't see this potential fault causing an intermitten issue like I'm seeing though. But it's an easy measurement.

Finding any fault is often just a process of elimination...............

[blue62]

Originally Posted by Bush Pilot

I can simply make a voltage measurement across the cable with one lead at the battery + and the other at the block where the alternator and starter tie in, located towards the front top of the engine. I don't see this potential fault causing an intermitten issue like I'm seeing though. But it's an easy measurement.

Your issue sounds like a possible bad ground to me.
This video will show you how to test for voltage drop on the ground (negative) side.
https://youtu.be/qdaOSiScEu8
Keep in mind there are multiple ground points on these cars.

[JFP in PA]

Originally Posted by blue62

Your issue sounds like a possible bad ground to me.
This video will show you how to test for voltage drop on the ground (negative) side.
https://youtu.be/qdaOSiScEu8
Keep in mind there are multiple ground points on these cars.

This is where the right tool makes your life easier: A Power Probe can do either positive or negative voltage drops from one tool in a couple of seconds.

[blue62]

Originally Posted by JFP in PA

This is where the right tool makes your life easier: A Power Probe can do either positive or negative voltage drops from one tool in a couple of seconds.

You just about have me ready to purchase one just to have it in the tool box

[JFP in PA]

Originally Posted by blue62

You just about have me ready to purchase one just to have it in the tool box

Look into them, very flexible and useful tools. We have both a PP Four and a Maestro, both of which are in constant use.

[blue62]

Originally Posted by JFP in PA

Look into them, very flexible and useful tools. We have both a PP Four and a Maestro, both of which are in constant use.

Thank you for the heads up... I will check them out