6.0L Vortec wiring short - Pirate4x4.Com : 4x4 and Off-Road Forum
 
Pirate4x4.Com : 4x4 and Off-Road Forum  

Go Back   Pirate4x4.Com : 4x4 and Off-Road Forum > General Tech > General 4x4 Discussion
Notices

Reply
 
Share Thread Tools Display Modes
Old 12-01-2010, 04:42 PM   #1 (permalink)
Rock God
 
Join Date: Nov 2008
Member # 123317
Location: Dallas
Posts: 1,152
6.0L Vortec wiring short

I know this is probably a hard topic for someone to diagnose online, but thought I would give it a shot. I've been to two electrician shops, going to the third tomorrow.

I have a 6.0L Vortec in my 1983 Jeep Scrambler and I have been having problems blowing alternators. I have a turn key engine supply computer and harness.

Took it to the electrical guy today and he said I have a full 12V when the ignition is off and I don't have a full 12V when the ignition is turned on. So the short happens after the ignition is turned on.

I'm thinking about sending the computer back to Turn Key and see if they can check it. Ran great for four years and started having problems recently. Everything looks to be hooked up correctly, according to the diagram turn key supplied me.

Could it be
1. Computer
2. Stock jeep harness
3. relays
4. ???

Any ideas or trouble shooting instructions would really be appreciated.
__________________
Scrambler - 6.0L, auto, atlas, 60's, 42in STICKY boggers
scramblerj is offline   Reply With Quote
Old 12-01-2010, 04:52 PM   #2 (permalink)
Registered User
 
Join Date: Mar 2009
Member # 132948
Location: sac ca
Posts: 81
check all of the grounds and the battery
natesd-max is offline   Reply With Quote
Sponsored Links
Old 12-01-2010, 04:56 PM   #3 (permalink)
Rock God
 
Join Date: Nov 2008
Member # 123317
Location: Dallas
Posts: 1,152
I think we checked all the grounds. Check the battery how? Do you mean, make sure it is good, holds a certain volts, or what? It's an optima, but I've been through a few over the past few years. I'll put in another battery and see what it does.
__________________
Scrambler - 6.0L, auto, atlas, 60's, 42in STICKY boggers

Last edited by scramblerj; 12-01-2010 at 04:58 PM.
scramblerj is offline   Reply With Quote
Old 12-01-2010, 05:05 PM   #4 (permalink)
Rock God
 
Join Date: Nov 2008
Member # 123317
Location: Dallas
Posts: 1,152
My ignition key has been feeling a little hard to turn. Do you think it could be staying on slightly causing a fluctuation in voltage?
or
spot lights not ground
or
stereo disconnected
or
speaker wires grounding out against vehicle since they are unhooked from speakers
__________________
Scrambler - 6.0L, auto, atlas, 60's, 42in STICKY boggers

Last edited by scramblerj; 12-01-2010 at 05:10 PM.
scramblerj is offline   Reply With Quote
Old 12-01-2010, 05:18 PM   #5 (permalink)
Registered User
 
Join Date: Jan 2008
Member # 106845
Location: Dayton, Ohio
Posts: 1,878
Send a message via AIM to flatlander757
The speaker thing will only happen if you are trying to play the radio. If radio is off then there will be no voltage going through them.

I would honestly ohm out how much resistance is in the ignition switch itself.

Have you checked the resistance in all of the alternator-related circuits? Battery to alternator, alternator to block(ground), etc etc?

Is the voltage regulator in the alternator itself or is it controlled by the PCM? Could be a bad PCM potentially.
__________________
-Tony
flatlander757 is offline   Reply With Quote
Old 12-01-2010, 05:23 PM   #6 (permalink)
Rock God
 
Join Date: Nov 2008
Member # 123317
Location: Dallas
Posts: 1,152
I don't know if they checked ohm resistance anywhere. I have a tester but haven't checked ohms before. How do you do it? I've only checked volts.

Im pretty sure the voltage regulator is in the alternator. Isn't the alternator ground through the engine to frame ground wire?
__________________
Scrambler - 6.0L, auto, atlas, 60's, 42in STICKY boggers

Last edited by scramblerj; 12-01-2010 at 05:25 PM.
scramblerj is offline   Reply With Quote
Old 12-01-2010, 06:29 PM   #7 (permalink)
Registered User
 
Join Date: Mar 2009
Member # 132948
Location: sac ca
Posts: 81
alternator ground through the engine to frame ground.....you can check ignition switch but check the ignition on power to the pcm check it make sure that its not a constant power cuz that will do it
natesd-max is offline   Reply With Quote
Old 12-01-2010, 06:31 PM   #8 (permalink)
Registered User
 
Join Date: Jan 2008
Member # 106845
Location: Dayton, Ohio
Posts: 1,878
Send a message via AIM to flatlander757
Quote:
Originally Posted by scramblerj View Post
I don't know if they checked ohm resistance anywhere. I have a tester but haven't checked ohms before. How do you do it? I've only checked volts.

Im pretty sure the voltage regulator is in the alternator. Isn't the alternator ground through the engine to frame ground wire?
Right on the alternator... just make sure it's not corroded on the alternator bracket or bracket to block or block ground wire to chassis.

For resistance, you do it with battery disconnected.

Set the DVOM to the "omega" symbol for measuring ohms, make sure your red lead is plugged into the ohm spot on the meter, place the meter leads on either end of the circuit you are testing.

It passes a small current from one lead to the other to check for continuity.

Usually about 0.2 ohms is normal for a good connection. You'll get 0.1-0.2 ohms if you touch the two DVOM leads together.

I don't think your problem is a "short" of any kind.... a short circuit generally will A) kill a fuse or B) start a fire.

It sounds to me like it is either high resistance somewhere causing additional strain on your alternator or you have some kind of issue with the alternator signal circuit that the PCM puts out:

Quote:
P1637

The powertrain control module (PCM) uses the generator turn on signal circuit to control the generator. A high side driver within the PCM allows the PCM to turn the generator ON and OFF. When Generator operation is desired, the PCM sends a 5 volt signal to the voltage regulator via the generator turn on signal circuit. This causes the voltage regulator to begin controlling the generator field circuit. Once the Generator is enabled by the PCM, the voltage regulator controls generator output independently of the PCM. Under certain operating conditions, the PCM can turn Off the generator by turning Off the 5 volt signal on the generator turn on signal circuit. The PCM has fault detection circuitry which monitors the state of the generator turn on signal circuit. If the fault detection circuit senses a voltage other than what is expected, this DTC will set. The voltage regulator also contains fault detection circuitry. If the regulator detects a problem, the regulator will ground the generator turn on signal circuit, pulling the voltage low. This also causes the PCM to set the DTC.
I would make sure that the PCM is sending that 5 volt signal to the alternator when your vehicle is running... if it is, then you can rule out the PCM.

If that's the case, I'd be checking ohming out all the alternator wires and make sure it is grounded really good. Take the DVOM and put one lead on the alternator case itself, and another on the battery negative terminal. Should be very low resistance(under 0.3 ohms ideally).

Are you caking your alternator in mud constantly? If so try flushing that shit out with a hose and it may just start working again. You could be legitimately fucking up every alternator you get

How many have you gone through in what time period?

What brand replacements have you used?


There is an interesting product safety TSB on GM alternators as well:

Quote:
#10117A: Product Safety - Voltage Regulator Internal
Low Resistance Short - (Jul 14, 2010)
The Service Procedure and Warranty Information sections in this bulletin have been
revised. The inspection date for determining a good generator has changed. Technicians
should review the new date codes immediately. Technicians are to record the date code of
the generator on the repair order.
Warranty Administrators are to record the generator date code in the Correction
Description field when the claim is submitted for payment.
Please discard all copies of bulletin 10117, issued June 2010.
Subject: 10117A - Voltage Regulator Internal Low Resistance Short
Models: Various Serviced Vehicles
Parts involved in this recall were used to service various GM vehicles. Dealers who
ordered these part(s) for service are identified in the attachment contained in the dealer
message announcing this recall. Please refer to the section titled, Dealer Recall
Responsibility, for additional details and instructions.
As an important precaution to prevent possible fire, until the inspection procedure for this
recall is completed, all vehicles should have both battery cables disconnected
immediately. Until the battery cables are disconnected, do not park these vehicles inside
a garage, car port or other structure.
Condition
Remy, who supplies generators to GM, has decided that a defect, which relates to motor vehicle
safety, exists in certain 145 amp generator. Some GM vehicles may have been serviced with these
generators. These generators may develop a low resistance short within the voltage regulator. If
this occurs, an open circuit could be created which would illuminate the generator lamp in the
instrument panel, or in some cases, cause an engine compartment fire.
Correction
Dealers are to inspect and, if necessary, replace the generator.
Dealers who have ordered the involved components for service have been identified in the report
that accompanied the dealer message announcing this recall. Identified dealers are to search their
That cut and paste came out all fucked up but I'm sure you can figure it out
__________________
-Tony
flatlander757 is offline   Reply With Quote
Old 12-01-2010, 06:33 PM   #9 (permalink)
Registered User
 
Join Date: Jan 2008
Member # 106845
Location: Dayton, Ohio
Posts: 1,878
Send a message via AIM to flatlander757
Quote:
Originally Posted by natesd-max View Post
alternator ground through the engine to frame ground.....you can check ignition switch but check the ignition on power to the pcm check it make sure that its not a constant power cuz that will do it
That will just cause a battery draw... won't cause a short or anything... and once it's running it wouldn't make a difference if it's ign-on power or constant-power... when the OP is having issues.
__________________
-Tony
flatlander757 is offline   Reply With Quote
Old 12-01-2010, 07:12 PM   #10 (permalink)
Registered User
 
Join Date: Mar 2009
Member # 132948
Location: sac ca
Posts: 81
look over your body harness and under dash it sounds more like a power grounding out when keys on have you done any new upgrades if so look over it may be it fuse box relays
natesd-max is offline   Reply With Quote
Old 12-01-2010, 07:51 PM   #11 (permalink)
Rock God
 
Join Date: Nov 2008
Member # 123317
Location: Dallas
Posts: 1,152
"Are you caking your alternator in mud constantly? If so try flushing that shit out with a hose and it may just start working again. You could be legitimately fucking up every alternator you get No, it will blow a new alternator very quickly. The tech working on it today said all my accessory items going through relays and fuses that should be getting the full 12v are only getting fluctuating numbers around 11v, if I quoted him correctly

How many have you gone through in what time period? I've gone through more than Autozone and Napa warranty would like, probably 8 or so

What brand replacements have you used? I've used different versions/amps from different year vehicles from Autozone and Napa, also blew a mean green once
__________________
Scrambler - 6.0L, auto, atlas, 60's, 42in STICKY boggers
scramblerj is offline   Reply With Quote
Old 12-03-2010, 12:46 PM   #12 (permalink)
Rock God
 
Join Date: Nov 2008
Member # 123317
Location: Dallas
Posts: 1,152
Does there have to be a direct ground from the battery to the frame?

New electrician shop will see if they can correct the problem of keyed ignition relays not getting a full 12v on Monday.

Ive also been told that there should be a 12v inline resistor on the alternator exciter wire.
__________________
Scrambler - 6.0L, auto, atlas, 60's, 42in STICKY boggers
scramblerj is offline   Reply With Quote
Old 12-03-2010, 06:26 PM   #13 (permalink)
Registered User
 
Join Date: Mar 2009
Member # 132948
Location: sac ca
Posts: 81
to the frame or engine and engine to frame
natesd-max is offline   Reply With Quote
Old 12-03-2010, 09:32 PM   #14 (permalink)
Registered User
 
Join Date: Jan 2008
Member # 106845
Location: Dayton, Ohio
Posts: 1,878
Send a message via AIM to flatlander757
Quote:
Originally Posted by scramblerj View Post
Does there have to be a direct ground from the battery to the frame?

New electrician shop will see if they can correct the problem of keyed ignition relays not getting a full 12v on Monday.

Ive also been told that there should be a 12v inline resistor on the alternator exciter wire.
Ideally there should be one from battery to the frame somewhere. Engine works too but make sure you have a cable from engine to frame as well(no matter what).

Alternator exciter wire? Not on anything new... the PCM basically sends a signal to the alternator itself(the internal voltage regulator)... it tells the alternator "yes charge this bitch up" or "oh fuck, stop charging motherfucker!"

As long as the PCM sends the alternator this signal, then the alternator is allowed to do it's voodoo with it's diodes and charge the system.

The only "resistor" that may be there is probably internal to the PCM since it converts a 12v to a 5v signal... I'd imagine it is integral to the PCM itself.
__________________
-Tony

Last edited by flatlander757; 12-03-2010 at 09:33 PM.
flatlander757 is offline   Reply With Quote
Old 12-13-2010, 03:56 PM   #15 (permalink)
Rock God
 
Join Date: Nov 2008
Member # 123317
Location: Dallas
Posts: 1,152
3rd guy to take a look got it fixed. He replaced a few wires so not exactly sure what he did that solved it, but I believe the exciter wire(or whatever you call it) going to the alternator was connected to a ignition hot wire that was not producing correct voltage from the battery. I'm guessing the fluctuation of volts was causing the alternator regulator to turn on and off so much it was blowing it. He replaced the charging wire to the alternator with a thicker gauge wire, and ran the exciter wire to a 12v keyed ignition wire in the fuse panel.

Works for now. We'll see after the next run.

I will post a more in depth description of the solution after I talk to the electrician and see the work.

Thanks for all the tips.
__________________
Scrambler - 6.0L, auto, atlas, 60's, 42in STICKY boggers

Last edited by scramblerj; 12-13-2010 at 03:57 PM.
scramblerj is offline   Reply With Quote
Old 12-13-2010, 04:46 PM   #16 (permalink)
Vortec Scout II
 
Bo185's Avatar
 
Join Date: Jun 2005
Member # 48545
Location: Arkansas / "The Stan"
Posts: 3,886
Blog Entries: 1
Quote:
Originally Posted by scramblerj View Post
3rd guy to take a look got it fixed. He replaced a few wires so not exactly sure what he did that solved it, but I believe the exciter wire(or whatever you call it) going to the alternator was connected to a ignition hot wire that was not producing correct voltage from the battery. I'm guessing the fluctuation of volts was causing the alternator regulator to turn on and off so much it was blowing it. He replaced the charging wire to the alternator with a thicker gauge wire, and ran the exciter wire to a 12v keyed ignition wire in the fuse panel.

Works for now. We'll see after the next run.

I will post a more in depth description of the solution after I talk to the electrician and see the work.

Thanks for all the tips.
What alt no you have?

I bet you were blowing the regular with stray voltage. Too much voltage to regulator will do that and blow it. You can put a 500 ohm resistor in the ignition wire if it keeps blowing it should help stop it.
__________________
'73 Scout II Vortec 6.0L 4L65e np241
'73 1210 Travelette SV392, T-34, 60/14bff 4.56's 35's
'01 VW Beetle TDI-50mpg or better!

GM Gen III/IV V8 swap info

TECH: Gen III/IV "LS motor" to Early GM Auto Trans
Bo185 is offline   Reply With Quote
Old 12-13-2010, 05:00 PM   #17 (permalink)
Registered User
 
Join Date: Feb 2006
Member # 66858
Location: Hudson, NH
Posts: 372
It is likely that the stock vehicle used the instrument cluster as a resistor. The regulator cannot take anything over 12V in most cases. Also, good braided ground from chassis to body and from engine to chassis.
__________________
Member
Deep Woods Extreme 4X4 Club Of Southern NH.
LASER is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On



All times are GMT -7. The time now is 06:40 PM.


Powered by vBulletin® Version 3.8.6
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Search Engine Optimization by vBSEO 3.6.0 ©2011, Crawlability, Inc.