Another "Electical Problems" thread *updated, fixed!*

[CoastalDefender]

Okay, so NAPA came through with the right Alt and a local alt/starter guy happened to have the correct pulley available. With a friend's help, we got the alt tightened up well.

Sooo... I still have problems.

At idle, the Batt and Oil lights are both on. Batt much more so than the oil light (100%/50% brightnesses).

When I increase throttle, the lights dim. Increase the throttle enough and they go out altogether.

With everything on (lights, heater) it sat and ran fine in my driveway.

I took it down the road a ways (2mi/3km) and everything remained fine. I turned back home, and that's when things began going bad. The lights dimmed, more so when brakes were applied, and I was worried about getting home. Not only did the lights dim, the fuel and temp gauges began to drop. However, the batt and oil lights remained out as long as my RPMs were up (driving), and the batt/oil lights would come back on when I dropped the engine to idle.


What order of things should I begin looking at testing?


Edit-
'82 1.6l NA diesel rabbit, w/o AC

[Powered by Spearco]

Wow, bad luck. Did you have any of these problems before the alt. change?
I'd check engine to body ground and battery to body grounds. Even add a ground from the body of atl. to engine. Battery conncetions?
The battery light will glow at an idle, but the oil light. I'd put an oil gauge at the head to verify, then work back from there, cause its most likely a wiring related issue.
Whats the condition of the Battery itself?
It sounds like something happened when changing the alt.

[CoastalDefender]

Wow, bad luck. Did you have any of these problems before the alt. change?

Yes I did. Exact same problems. Which led me to getting the alt tested and replaced.

I'd check engine to body ground and battery to body grounds. Even add a ground from the body of atl. to engine. Battery conncetions?

I'll try that tonight after work.

The battery light will glow at an idle, but the oil light. I'd put an oil gauge at the head to verify, then work back from there, cause its most likely a wiring related issue.
Whats the condition of the Battery itself?

Interstate Reman. And at this point, suspect. I've ran it down twice now. First time with the first alt, then last night as well

It sounds like something happened when changing the alt.

Well, something did happen. Everything worked real well for the first few miles. I had everything disconnected when I swapped alts, I don't think anything could have happened to the unit.

[burn_your_money]

Test to make sure that the alt is still putting out around 14.0V with the car running.

It does sound like a grounding issue to me. Have you done a voltage drop test?

[CoastalDefender]

Test to make sure that the alt is still putting out around 14.0V with the car running.

It does sound like a grounding issue to me. Have you done a voltage drop test?

No I haven't. In my limited searches, I'm still fuzzy in how to do a voltage drop test. I'll search more, thanks for the lead.

Also, is there somewhere that has the physical location(s) of the engine ground strap? And where on the alt should I be grounding to the engine/body?

[burn_your_money]

http://www.vwdiesel.net/forum/index.php?topic=22321.0
Here is the DIY I wrote up.

Just follow the ground strap and you will see the locations.

Ground the alt to the engine. Mine is grounded to under one of the vacuum pump bolts.

[CoastalDefender]

http://www.vwdiesel.net/forum/index.php?topic=22321.0
Here is the DIY I wrote up.

Just follow the ground strap and you will see the locations.

Ground the alt to the engine. Mine is grounded to under one of the vacuum pump bolts.

Thank you.

I also found these after a quick search-
http://www.vwdiesel.net/forum/index.php?topic=14191.0
http://www.vwdiesel.net/forum/index.php?topic=21220.0


Edit- Holy crap, that DIY you wrote up is awesome!

[burn_your_money]

Haha thanks. Maybe I should call in sick more often

[CoastalDefender]

Okay, did the tests in the DIY. Showed bad loss at the starter. Also, I noticed a PO moved the 30-1/2 wires from the starter post to the + on the battery. Is this a bad deal?

So I noticed I am losing a lot of voltage in between the alternator and the 30-1/2 wires (man, I hope I am calling those wires correctly).

The battery is only charging at 12.5, but the alt is putting out 14.6v...

I cleaned up the connections at the batter +/-, the 30-1/2 terminals, and the connection at the starter. It charged better, but not proper.

So I pulled the 30-1/2 disconnects and cleaned the insides out, they must have been good enough, as there was little change.

So I am losing power in the 30-1/2 area somewhere... About 3v or so...




I'm going to have to rip apart the whole wiring harness, aren't I?

[Powered by Spearco]

Why tear the harness apart. Bypass it by means of a new harness and test for voltage.
I guessing the 30-1/2 is the alt. harness. Two red 8 gauge and one blue 18 gauge, in one plug right? Thats the one I ment bypassing.
If its the single plug type, they are worthless anyway. Make new, better one.
It sounds like the alt. is charging, but the voltage isn't getting to the battery.

[CoastalDefender]

Why tear the harness apart. Bypass it by means of a new harness and test for voltage.
I guessing the 30-1/2 is the alt. harness. Two red 8 gauge and one blue 18 gauge, in one plug right? Thats the one I ment bypassing.
If its the single plug type, they are worthless anyway. Make new, better one.
It sounds like the alt. is charging, but the voltage isn't getting to the battery.

It had occurred to me to bypass it with a direct line to the battery. But if I do, I am still getting bad heat somewhere in the harness? Also, what size fuse would I run?

If I get home when it's still light out tonight, I'm taking pictures.

[somolovitch3]

The 30-1/2 he is talking about are the leads to the fusable links, I believe. There should be two 14 ga red leads from the alt to a juntion that the all the other power leads come from/goto. If it is a 90 amp alt there is a single 8 ga that goes from the alt post to the starter post or to the battery pos.

It sounds like he lost the alt to batt charging lead somewhere. Maybe his fuseable links fried? A quick test would be to run a temp line from the alt post to the pos batt post and see if he gets 14 volts then.

[Rabbit on Roids]

Why tear the harness apart. Bypass it by means of a new harness and test for voltage.
I guessing the 30-1/2 is the alt. harness. Two red 8 gauge and one blue 18 gauge, in one plug right? Thats the one I ment bypassing.
If its the single plug type, they are worthless anyway. Make new, better one.
It sounds like the alt. is charging, but the voltage isn't getting to the battery.

It had occurred to me to bypass it with a direct line to the battery. But if I do, I am still getting bad heat somewhere in the harness? Also, what size fuse would I run?

If I get home when it's still light out tonight, I'm taking pictures.

if you need help with any of it, let me know, im a cracker jack when it comes to these mk1 rigs. besides, i had to make all the wires in my 81 work correctly and THAT was no small feat.

[CoastalDefender]

if you need help with any of it, let me know, im a cracker jack when it comes to these mk1 rigs. besides, i had to make all the wires in my 81 work correctly and THAT was no small feat.

Thank you for the offer. I might end up taking you up on it, so be warned.

I think I discovered the problem today.

Fuel Shutoff Solenoid wire. Comes out of the Black connector, in position 1 (bentley manual). The harness is fine going back to the fuse panel, but leaving the harness to the engine compartment, it's fried.

Followed it all the way to the fuel shutoff solenoid. And the PO seems to have butt connected the wire from where it comes out of the harness near the solenoid.

Pics-








Will it be possible to just run another wire in it's place?

I have cleaned up all the relay/fuse/starter/battery/ground/alt cables... And I am thinking the bad grounds/connectors were the reason for the heat buildup and subsequent toasting off of the solenoid wire. Is this probable? Or am I off base in this assumption?

[CoastalDefender]

And after this discovery, frankly I am surprised I was able to drive it around without it dying on me for all this time...