Barthmobile Portal
84 Barth...electrical problem.

This topic can be found at:
https://www.barthmobile.com/eve/forums/a/tpc/f/3631087061/m/7331068042

03-21-2007, 02:39 PM
jrdwyeriii
84 Barth...electrical problem.
Well, I got my alternator rebuilt, installed it, and wanted to shorten the two 14ga leads to the alternator. Mistakenly cut them both at the same time. According to the electical prints, one is for ignition and one goes to the battery. These are not the two 4ga wires going to ground and the battery isolator.

Heard a clunk and something. Not sure what I did, but now when I turn the key switch to run (not start) the engine begins to turn over. I checked out the key switch, and it is not shorted between the run and start position. Any ideas where I can look next?

It appears there is a short between the battery and the starter solenoid...because when I take those two 14ga leads that went to the alternator, and touch them, the engine turns over.

Thanks,
John


1984 35' Regency MCC
8.2 DD, 545 Allison
03-21-2007, 05:45 PM
Gunner
"one is for ignition and one goes to the battery." "I take those two 14ga leads that went to the alternator, and touch them, the engine turns over."

When you touch them, the "battery" wire sends power through the "ignition" wire telling the starter to crank - n'est-ce pas?" Try reversing the wires. OR... am I mis-reading the problem?


"You are what you drive" - Clint Eastwood
03-21-2007, 08:21 PM
Rusty
Gunner's diagnosis sounds right.


Rusty


MilSpec AMG 6.5L TD 230HP; built-to-order by Peninsular Engines:  Hi-pop injectors, gear-driven camshaft, non-waste-gated, high-output turbo, 18:1 pistons.  Fuel economy increased by 15-20%, power, WOW!"StaRV II"

'94 28' Breakaway: MilSpec AMG 6.5L TD 230HP

Nelson and Chester, not-spoiled Golden Retrievers

Sometimes I think we're alone in the universe, and sometimes I think we're not.
In either case the idea is quite staggering.
- Arthur C. Clarke

It was a woman who drove me to drink, and I've been searching thirty years to find her and thank her - W. C. Fields
03-22-2007, 12:54 AM
jrdwyeriii
I'll try to explain a different way. There are three wires attached to the key switch. One is battery, one is ignition, and one is start. So when you turn the key to "run", it connects the battery to the ignition...this is what usually powers everything in the coach. When you turn it a little further, to "start" it sends power to the solenoid on the starter, which then turns your starter, and starts your engine. With the two 14ga wires going to the alternator, disconnected, and turning the key from "off" to "run" the engine turns over.

This tells me, when I cut the two wires at the same time, that go to the alternator, I shorted the ignition wire to the starter/solenoid wire...therefore, when the key is put to the "run" position, it is not only connecting power to everything it normally does in the "run" position, but also connecting power to the solenoid on the starter.

Therefore, switching the two leads does not come into play, as they can be hanging in the air, and this will still happen. It has to be something between the starter and the key switch, or some other device that is allowing power to connect to the starter solenoid, when I put the key in the "run" position. Any idea what device may be doing this? or is it simply a melting of two wires together? No idea...never run into this before, and when connecting the battery to the ignition (the two wires going to the alternator) should not have caused this. It should really have acted like I was turning the key to the "run" position...right? or am I missing something?

Thanks,
JOhn


1984 35' Regency MCC
8.2 DD, 545 Allison
03-22-2007, 01:17 AM
Rusty
I'm lost...I thought the issue was that all worked normally until you cut and reinstalled the wires to the alternator and the other.

If that's the case, wires to the start switch don't come into play.

If you're getting engine cranking without these two wires being connected correctly, then the issue is backfeed. You still need to install those two wires into their correct homes, and then go from there. Try reversing the wires' connections, and see what the results are. This is why, whenever I disconnect wires, I label 'em.


Rusty


MilSpec AMG 6.5L TD 230HP; built-to-order by Peninsular Engines:  Hi-pop injectors, gear-driven camshaft, non-waste-gated, high-output turbo, 18:1 pistons.  Fuel economy increased by 15-20%, power, WOW!"StaRV II"

'94 28' Breakaway: MilSpec AMG 6.5L TD 230HP

Nelson and Chester, not-spoiled Golden Retrievers

Sometimes I think we're alone in the universe, and sometimes I think we're not.
In either case the idea is quite staggering.
- Arthur C. Clarke

It was a woman who drove me to drink, and I've been searching thirty years to find her and thank her - W. C. Fields
03-22-2007, 01:24 AM
jrdwyeriii
Everything was normal until I cut the two wires going to the alternator, at the same time. I heard a clunk (which now I believe to be the engine turning over or some device blowing up). Now I have this problem with the engine turning over when I put the key to the "run" position. Something happened when I cut these two wires at the same time...something shorted out. Now...whether the two wires are connected or hanging in the air...the engine turns over when I put the key in the run position.

Thanks,
John


1984 35' Regency MCC
8.2 DD, 545 Allison
03-22-2007, 05:50 PM
Gunner
Perhaps: The "clunk" was the starter solenoid welding itself "closed" so it is forever "engaged"; when you put the key in "run" -or touch the two wires -you are energizing the starter motor, causing the starter motor to turn (and turning the engine). Normally the starter motor starts turning when the flywheel gear moves forward (and stops when the arm retracts), so if it is already forward -as (mebbe?) now- it will spin on any application of power. You always have power to the starter motor, and it actuates whenever the flywheel arm moves forward, so technically this is possible, FARFETCHED AS IT MAY BE. Can you see the starter solenoid arm, and is it forward when the key is off?
Good Luck


"You are what you drive" - Clint Eastwood
03-22-2007, 09:18 PM
Rusty
I don't theink the solenoid has welded itself, otherwise the engine would turn over constantly, since the solenoid contacts connect the battery directly to the starter motor.

What may have happened is the start-disconnect relay may have fused (or not - see below). This is the relay that disconnects the load (that's connected when the key is in the "run" position) when the key is turned to "start".

But I still like your first answer, that the wires are reversed. With the wires disconnected, the start-disconnect relay is in the closed position, and may be backfeeding into the starter motor.


Rusty


MilSpec AMG 6.5L TD 230HP; built-to-order by Peninsular Engines:  Hi-pop injectors, gear-driven camshaft, non-waste-gated, high-output turbo, 18:1 pistons.  Fuel economy increased by 15-20%, power, WOW!"StaRV II"

'94 28' Breakaway: MilSpec AMG 6.5L TD 230HP

Nelson and Chester, not-spoiled Golden Retrievers

Sometimes I think we're alone in the universe, and sometimes I think we're not.
In either case the idea is quite staggering.
- Arthur C. Clarke

It was a woman who drove me to drink, and I've been searching thirty years to find her and thank her - W. C. Fields