msd6 -tach-run on - Off-Road Forums & Discussion Groups
Jeep-Short Wheelbase All discussion of short wheelbase Jeeps: CJ, TJ, YJ and JK

Reply
 
LinkBack Thread Tools Display Modes
post #1 of (permalink) Old 12-07-2001, 03:38 PM Thread Starter
 
Join Date: Nov 2001
Posts: 40
Thanks: 0
Thanked 0 Times in 0 Posts
 
msd6 -tach-run on

did "TR" upgrade- all but adv. springs-{will put in later}-runs great !!! except tach does not work- tried to reveiw old posts but could not find anything w/ specific instructions- read about adapters and extra wire from tfi coil -any insight would be appreciated-- thanks luke

is thier reality apart from our selves
luke6028 is offline  
Sponsored Links
Advertisement
 
post #2 of (permalink) Old 12-07-2001, 04:03 PM
**DONOTDELETE**
Guest
 
Posts: n/a
Re: msd6 -tach-run on

Pull out your MSD instructions. It spells out your problem and it's fix in there. You will have to place a diode in line with one of the wires on the alt.(brown wire, I belive on Delco alts.).




Jason

----------------
OIIIIIIIO'81 Scrambler & '88 Grand Waggie
I'm stuck in the '80's!

post #3 of (permalink) Old 12-07-2001, 04:16 PM
I Might Just Know What I'm Talking About
 
ricochet's Avatar
 
Join Date: Mar 2000
Location: New Jersey
Posts: 1,526
Thanks: 0
Thanked 0 Times in 0 Posts
 
Re: msd6 -tach-run on

I had to put the diode in to get the truck to turn off. As for the tach, I had to purchase a tach adapter from msd. You can check out pics of the diode along with my write up at http://www.dreamwater.com/ironpines/...onupgrade.html

Keith

ITS GOOD ENOUGH [img]/wwwthreads_images/icons/wink.gif[/img]

http://www.dreamwater.com/ironpines
ricochet is offline  
Sponsored Links
Advertisement
 
post #4 of (permalink) Old 12-07-2001, 04:17 PM
Way Outta Control
 
Join Date: Sep 1999
Location: The Palouse
Posts: 13,432
Thanks: 1
Thanked 3 Times in 3 Posts
 
Re: msd6 -tach-run on

MSD stands for "Multiple Spark Discharge" and it's how MSD made money. They spark the plug multiple times over the dwell cycle. Because the ignition module is involved in creating the pulse to spark the plug the Tach becomes involved. The Tach recieves it's signal, usually off the coil. If you've got it hooked to a MSD system without a filter... it's going to attempt to read each pulse. This is going to cause the Tach to go nuts, it's not engineered for such a thing. Get a Tach Adapter PN 8910 filter from MSD, it'll cure the problems.

LEVE is offline  
post #5 of (permalink) Old 12-07-2001, 05:34 PM Thread Starter
 
Join Date: Nov 2001
Posts: 40
Thanks: 0
Thanked 0 Times in 0 Posts
 
Re: msd6 -tach-run on

thanks for replies- looks like i'll need to order an adapter--luke next step carb--weber -motorcraft-holley or ??????? 1990 4.2 yj

is thier reality apart from our selves
luke6028 is offline  
post #6 of (permalink) Old 12-09-2001, 10:43 AM Thread Starter
 
Join Date: Nov 2001
Posts: 40
Thanks: 0
Thanked 0 Times in 0 Posts
 
Re: msd6 -tach-run on

leve- saw other posts that mentioned msd tach. adapter 8920 not sure which one to use--1990 yj 4.2- w/msd6a & tfi- or is there another way to wire msd so you wont need adapter-heard mention of not bypassing knock sensor-- thanks

is thier reality apart from our selves
luke6028 is offline  
post #7 of (permalink) Old 12-09-2001, 11:53 AM
 
Join Date: Sep 1999
Posts: 5,383
Thanks: 0
Thanked 1 Time in 1 Post
 
Re: msd6 -tach-run on

The guys say the Rochester Quadrajet does the best on severe angles.
( I prefer Holleys, but I can see their limitations...)

I don't have a clue about two barrel carbs...
Ideas or comments anyone?
----------------
MSD problem,

Do this test...
With the key off, and the vehicle still running on, unplug the two wire connector from your alternator and see if the engine dies. If so, read on...

If you are having run on problems with the MSD 6 series module, you wired the small red of the MSD module to what was the old Red wire to the ignition coil. (this is proper connection)

You will need a diode here. The exciter feed for the alternator is connected to that circuit.
The residual alternator output is enough to switch on the MSD module, or keep it on in your case.
(MSD only requires a few tenths of a volt to switch on, and the alternator output will be a few volts)

The factory used a resistor wire in days of old to keep this run on from happening with the factory ignition, but alternators have become more efficient, and powerful, and the MSD requires less voltage to switch it on...
(The factory replaced the resistor wires with diodes in later years)

SO...

Now a diode is in order.

You will place a diode (available from MSD or Radio Shack) in the #1 wire to the alternator. (small wire in the plastic plug).
You want the 'arrow' to point towards the alternator. The graphic for the wiring will look like this,
Wire in ---->I-----Alt. plug.
Arrow pointing toward the alternator.
Very simple, very easy to do.
If you want the Radio Shack part number let me know and I'll find it for you. Diodes under $3 at Radio Shack.
------------------

SIDE NOTE...
If you left the factory ignition module in place, but don't use it in your MSD install, make sure you unplug the two wire connector on the DuraSpark Modules so they don't sit there powered up doing nothing while the vehicle is running...

------------------

Tach problem...

MSD has a tach terminal built into the side of the module. If your tach doesn't work connected there,...

Someone figured out how to use the factory tach with an MSD box without a tach adaptor...
If I remember correctly it had to do with a Howell Injection set up and it was on that Howell/ MSD thread... (and my memory is about as long as my pud... so I'm not sure what my name is this morning...[img]/wwwthreads_images/icons/crazy.gif[/img])
Might do a search and see what you come up with...

Start a post asking 'MSD/ Factory Tach Questions...' and see what you come up with.

So many cats, so few recipes...
Junk Yard Genius is offline  
post #8 of (permalink) Old 12-09-2001, 01:55 PM
**DONOTDELETE**
Guest
 
Posts: n/a
Re: msd6 -tach-run on

I havn't tried this but I think if if you use the stock ignition box to trigger the MSD unit the tach will work without the adapter.
It's on page 18 of my instructions, Wiring a Ford Duraspark using White Wire Trigger.
Wiring it this way you're still using the stock module to trigger the MSD, therefore your tach is receiving the trigger signal BEFORE it gets to the MSD.
I"m wondering if using the stock module enhances or detracts from the MSD's potential? TR?
IMO, if it detracts from the MSD then I would opt for the tach adapter.
The only thing I can think of that is different is that the stock module will control the dwell instead of the MSD doing it.

CTjeepnut

You had to do what to fit those little tires?
I'm sure glad I own a CJ!
post #9 of (permalink) Old 12-09-2001, 03:07 PM Thread Starter
 
Join Date: Nov 2001
Posts: 40
Thanks: 0
Thanked 0 Times in 0 Posts
 
Re: msd6 -tach-run on

ct---where do i find page the the instructions for Ford Duraspark using White Wire Trigger.also i was wondering also if there was any performance lost by going through stock module--"tr" any help? thanks luke

is thier reality apart from our selves
luke6028 is offline  
post #10 of (permalink) Old 12-09-2001, 03:13 PM Thread Starter
 
Join Date: Nov 2001
Posts: 40
Thanks: 0
Thanked 0 Times in 0 Posts
 
Re: msd6 -tach-run on

thanks "tr" a diode came w/ msd6 kit ill give that a try-if you read CT post he was wondering "as am i" if it mattered if msd goes through stock module-- tried to go through some of the -howell threads- kind of slow searching-search engine not to friendly-or not using it properly thanks luke

is thier reality apart from our selves
luke6028 is offline  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Off-Road Forums & Discussion Groups forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



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

 
For the best viewing experience please update your browser to Google Chrome