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-   -   MSD rev limiter verification (https://forums.maxperformanceinc.com/forums/showthread.php?t=881063)

scott70 07-05-2025 10:52 AM

MSD rev limiter verification
 
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I’ve got the RTR distributor and I can’t get the limit verification as when you get in the car and turn the key on,, it’s supposed to show you every time you cycle the key where you have your limit set. I’m using the Ames in dash tach in my 70 gto. You can set the limit and the limiter works. It even shows you where it’s set on tach after you take the ground away. I held it at 2900, grounded the wire, released and it showed 5800. I shut the ignition off, turn it back in the on position but it still goes to 8k and back to zero. Obviously I’m doing something wrong. I even found online how you can enable and disable the limit verification but that procedure doesn’t work either.

Holeshot71 07-05-2025 12:33 PM

Try just tapping once on the ground. They are sensitive to how long you hold it to ground.

scott70 07-05-2025 01:15 PM

I can try that,, I tried from 2 seconds to ten. But won’t show limit rpm. To enable verification you’re supposed to hold grey wire on ground, turn on key for 5 seconds and then remove wire from the ground . Nothing. I’d just like to see and verify rpm limit when I turn on key. Not going to rev it to 5900 to check,, lol. I did set it at 2200 and it wouldn’t rev over that so I do know it works.

JLBIII 07-06-2025 12:08 PM

I'm having the same problem with the MSD RTR distributor rev limiter. My car is a '68 Firebird with hood tach. Tried setting it according to instructions. The tach is supposed to show what rev it is set to when you turn the key on. Nothing happens on my tach. When I took my car in to be dyno'd we tried to set it again but still got the same result. The dyno operator has worked with these units before and felt the limiter was set, just not showing up on the tach. I'm not really comfortable with this and plan to reset the limiter to a much lower rpm to see if it's really working.

Formulajones 07-06-2025 12:41 PM

I have an msd box that shows the limit on the factory tach. It's just a digital 6 that has rev limit and capacitive discharge, and I trigger it with the stock points distributor.

I don't have to do anything fancy with ground wires, just turn the knob to your rev limit and it shows on the tach every time I turn the key on.

I had an msd module in an hei distributor once that did what you described and that worked fine. Sounds like maybe a faulty msd rtr distributor??

scott70 07-06-2025 01:24 PM

Quote:

Originally Posted by Formulajones (Post 6572011)
I have an msd box that shows the limit on the factory tach. It's just a digital 6 that has rev limit and capacitive discharge, and I trigger it with the stock points distributor.

I don't have to do anything fancy with ground wires, just turn the knob to your rev limit and it shows on the tach every time I turn the key on.

I had an msd module in an hei distributor once that did what you described and that worked fine. Sounds like maybe a faulty msd rtr distributor??

I figured I’d start here with the question in case someone knew what’s up. Every thing works correctly except for the verification when you turn the key on. Even the verification right when you set the limit works, I hold it at 2900, ground it out, release and the tach needle goes to 5800 and then back to idle. And it sounds like the verification can be disabled because with fuel injection it can mess with it . I thought I had finally figured it out when I found that procedure for enabling the verification but still nothing.

jwcfbd 07-06-2025 08:35 PM

Quote:

Originally Posted by JLBIII (Post 6572008)
I'm having the same problem with the MSD RTR distributor rev limiter. My car is a '68 Firebird with hood tach. Tried setting it according to instructions. The tach is supposed to show what rev it is set to when you turn the key on. Nothing happens on my tach. When I took my car in to be dyno'd we tried to set it again but still got the same result. The dyno operator has worked with these units before and felt the limiter was set, just not showing up on the tach. I'm not really comfortable with this and plan to reset the limiter to a much lower rpm to see if it's really working.

Are you running the gray wire from the MSD to your hood tach? When I tried that on my 67 it wouldn't work at all. I have to run it from the coil and would have to install a different tach that works by the msd in order to set my limiter.

JLBIII 07-06-2025 11:45 PM

Quote:

Originally Posted by jwcfbd (Post 6572063)
Are you running the gray wire from the MSD to your hood tach? When I tried that on my 67 it wouldn't work at all. I have to run it from the coil and would have to install a different tach that works by the msd in order to set my limiter.

Yes, the gray wire is hooked up to my hood tach. The tach does function with the gray wire hooked up, just not sure that the rev limiter is set.
Once you set your limiter using a different tach were you able to reconnect the gray wire to the hood and have the rev limiter still work?


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