MSD Tech Support Forums

Go Back   MSD Tech Support Forums > MSD Ignition Forums > Installation Questions

Installation Questions Wiring and Tech Information

Reply
 
Thread Tools
  #1  
Old 07-09-2005, 03:52 PM
gto4fun gto4fun is offline
Junior Member
 
Join Date: Jul 2005
Posts: 3
Default

I bought a 68 GTO that has a MSD 6AL and a 8920 tach adapter. Tha tach is an aftermarket hood tach that he bought from Original Parts Group (KR00152). The way he has it hooked up appears right for a Voltage triggered tach but it does not work. The lights on the tach work so there is power.

My questions are do I have the right adapter and is there any way to tell if a tach is a voltage or current triggered? Or is there a way to test and see if the trigger wire is getting a signal?

I had sent the tach back to OPG to test and they said it worked fine but sometimes had problems with MSD products. They were unsure why and could not give me any real reasons.

Help not having a tach is driving me crazy.
Reply With Quote
  #2  
Old 07-10-2005, 02:00 PM
my428 my428 is offline
Junior Member
 
Join Date: Jul 2005
Posts: 1
Default

I am having a similar problem on a 68 firebird. I'm running a unilite and a 6al box, with an aftermarket hood tach (verified good on another vehicle), and I just can't get it to work on my 'bird. From reading the forum and paperwork, it appears that we both need an 8910 tach adaptor, but lets wait on the pros to answer!!
Reply With Quote
  #3  
Old 07-13-2005, 09:00 AM
msdtechsupport1
Guest
 
Posts: n/a
Default

GTO4FUN;

If you're using the green and violet wires on the MSD to trigger the unit, then the 8920 is the correct adapter. That particular tach is a voltage triggered type. If the tach is not working, check the voltage coiming out of the tach output on the MSD. Make sure nothing is plugged into the tach output and start the engine. You should see anywhere from 1.5 to 5 volts. If that checks out, reconnect the adapter to the tach output, start the engine and check the voltage coming off of the violet wire on the 8920. There, you should see 12 volts approximately.

MY428;

That is the correct adapter to use for your application. However, since the 8910 does not tie into the tach output on the MSD, there really is no way to check it. Make sure that the tach wire is connected to the white wire on the 8910. This should also be tied into the white wire on the MSD.
Reply With Quote
  #4  
Old 07-14-2005, 08:13 PM
gto4fun gto4fun is offline
Junior Member
 
Join Date: Jul 2005
Posts: 3
Default

Thanks for the help. Well I did what you said and here is what happened. At the tach output I got readings of just over two volts (2.06 to 2.15), I then measured the purple wire and got basically nothing (0.01). I also looked at the connection of the red wire from the tach adapter and saw over 13V. There are two lights in the tach itself that use the same red and ground connections and they are both working when the ignition is on.

OK, so now what? How do I check verify the 8920 is working correctly? Or what else can I do here?
Reply With Quote
  #5  
Old 07-15-2005, 10:02 AM
msdtechsupport1
Guest
 
Posts: n/a
Default

If you did not get any voltage at the violet wire on the 8920, then the unit is defective. Make sure you measued this when the engine was running. If so, then you'll either have to have the dealer you purchased it from exchange it for you, or you can send it into our repair department. The latter will require you to call our customer service department for an RMA number.
Reply With Quote
  #6  
Old 06-18-2006, 06:42 PM
gto4fun gto4fun is offline
Junior Member
 
Join Date: Jul 2005
Posts: 3
Angry New adapter Not working

I still need help with this. Let me go back and summerize. I have a 68 GTO with a MSD 6AL ignition being used on a 428 engine and an aftermarket hood tach from Original Parts Group. It had a tach converter that was not working. With the engine running I measured the voltage at the tach output and saw around 2.10. I measured at the purple wire and get basically nothing. You told me that it looked like the adapter unit was defective. Well I bought a second adapter and I am in EXACTLY the same situation. 2.10 at the tach output and 0 at the purple wire. I also tried to measure the red wire on the adapter and got 0.

As a experiment I connected the red wire together with the red wire from the ignition. When I did this the engine would crank but would not turn over. I took it off and the engine started immediately.

Help, this is driving me nuts. More information I can offer is I was told the tach is ignition controlled. I can't take the second unit back as the store said they do not accept any returns on this part so I am out the cost and no better off.

Thanks in advance.
Reply With Quote
  #7  
Old 06-20-2006, 09:18 AM
msdtech16's Avatar
msdtech16 msdtech16 is offline
Tech Support
 
Join Date: Mar 2006
Posts: 1,169
Default

at this point it would be best to send both the tach and the MSD box to us for testing. Please call MSD at 915-855-7123 and request a RMA number for return.
Reply With Quote
Reply

Bookmarks

Thread Tools

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

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Tach Output On 6t Mooreboys Trouble-Shooting 13 07-25-2005 10:39 AM
Tach Woooos!!!! luccamaro68 Trouble-Shooting 4 04-28-2005 09:19 AM
Msd 6al Tach Trigger Output ... Test? Monstermach Trouble-Shooting 7 01-18-2005 01:48 PM
Msd 8572 Mechanical Tach Drive Distributor.... Flared69 Trouble-Shooting 2 12-10-2004 05:06 PM
Tach wont read past 3000 rpm Blue Fastback Trouble-Shooting 5 09-11-2003 10:19 AM


All times are GMT -6. The time now is 05:28 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
2011 MSD Performance