I just Installed a MSD 6a WHAT A difference 100%
Now my tach will not work. I have searched the forum for what I need to do. I have found no real answer some use the MSD adapter 8910 others the 8920.
I have a 73 fuel injected 2.0 with pertronix. According to MSD the 914 (mine) the tach wire used to go to the Negative of the bosch coil and it is called a Voltage Trigger and says to use the 8910. I have read others using the 8920 with no problem. below are two diagrams I found. Which is the correct one to use
8920
8910
THANKS
I found this on line about the 8920
http://www.msdignition.com/forum/archive/index.php?t-8649.html
I made the 8920 diagram and that post on MSD's forum is mine. I used the 8920 because it came with my box when I bought them used. It works fine. Well it did at least until the 6AL box failed! I *think* you can use either adapter. But I know the 8920 works.
If you can't get it to work with either MSD adapter PM me.
Thanks for the information
I just came across this on the forum that explains how to do a little modification on the Tach internals by using a jumping cable. Has any one tried this or is it safer just to spend the extra about $70 for the MSD adapter 8920
http://www.914world.com/bbs2/index.php?act=ST&f=2&t=28992&hl=hyfire,and,tach
Here's my http://www.914world.com/bbs2/index.php?showtopic=53368&hl=msd+tach when I finally got it to work...
-- Rob
I dont think you need an adapter....
The dizzy tells the BOX when to fire the coil right?
Hmm... the only wire coming out of the dizzy to the box is a signal wire.....
you should be able to tee into that wire and have a tach pulse (it used to be the wire going to the negative side of the coil before the box was installed)
works with my mallory box and dizzy this way
Yes.. the white wire in both mallory and MSD 6a boxes is a trigger wire. 1 pulse per plug (the box decides when to do multispark discharge... not the dizzy)
Tee into the white wire out of the MSD 6a box
Thanks Aaron I am going to try what you said. If it does not work for me Then I am going to buy the 8920 adapter.
Ditto what Aaron said.
I've got a Unilite and MSD 6a running with no tach adapter.
Do a search for MSD installation, or tach adapter; and you should be able to find the wiring setup diagram. Fact is, I've got a brand new un-opened 8910 I bought just in case, and never needed it.
Mike
VDO tach's require at lease 125 volt voltage spike to work. It uses the back
EMF off the stock coil to work.
I just got the MSD adapter 8920 it cast me $70.00 ArtechnikA I agree with you all this money for a transformer.
I will install this week end i will post some pictures of the install I will be using the diagram posted above to install.
I Installed the MSD adapter 8920 according to the diagram above it worked PERFECT.
THANKS jasons
JC
Hello,
I just installed my MSD 6A and I cannot get the engine to run. It will only crank. I used the diagram above for the 8920 tach adapter. I unplugged everything and connected the original set up and it runs, so everything works. Any suggestions as to what I am doing wrong?
Attached thumbnail(s)
Correction 8910*
i've been running a 6A with 8910 for 15 yrs, later added an MSD timing control, with points at first, and with a Pertronix for at least 10 yrs - never any problems
I've got an 8910 new in box sitting on the garage floor. Technically, you don't need it. JCD914 helped me install mine and he just took a wire and connected it to the tach output on the MSD box and ran it to the coil... IIRC. I am putting two MSD 6AL boxes and the tach adapter on eBay today unless someone here wants it... Cleaning up the stuff I don't need..
I suppose my first question would be, are you sure the MSD box is good?
Have you double-checked all of your wiring and connections?
Mike
Where did you get the MSD box? Used?
You to start a new thread of your own next time. Old post confused with new posting, etc... Try it; You'll like it.
Glad to hear it was something simple!
lol, me too. Thanks
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