Having trouble with MSD7AL3 Ignition November 15, 2010 08:25AM
We are running fuel injected 582 chevy's with MSD7AL3 ignition. They sometimes misfire out to about 200 feet then clean up and run right but by then its too late. Its not a fuel problem. Anyone have any ideas on how to solve this? Could it be a bad coil or rev chip? These engines are all new components. Maybe we should be using mags?
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Re: Having trouble with MSD7AL3 Ignition November 15, 2010 09:00AM
Buy an 8 box and sell the 7.
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Re: Having trouble with MSD7AL3 Ignition November 15, 2010 12:22PM
ok, thanks!
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Re: Having trouble with MSD7AL3 Ignition November 15, 2010 12:38PM
Have you sent the box to Msd for a checkup? This may sound weird but be sure not to over voltage charge your batteries, if I remember correctly 14.7 volts or more will cause the box to act up and finally just quit. Mike
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Re: Having trouble with MSD7AL3 Ignition November 15, 2010 12:39PM
Just take the chip out for a run and try that too!
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Re: Having trouble with MSD7AL3 Ignition November 15, 2010 01:13PM
Thank you
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Re: Having trouble with MSD7AL3 Ignition November 15, 2010 01:42PM
some options
remove rev chip, do not just put in a higher one.

Make sure the cap is dry inside, blow it with a hair drier on the inside.

how long have you had your plug wires on? Replace them, or at least The coil wire to distributor

how big is your plug gap, reduce it to .014-.016

what make plugs are you using, have they been fowled out then dried? replace the plugs, Ngk 1st choice, 2nd champion.

how are you firing the box, points or magnetic pickup? points is the spring week?
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Re: Having trouble with MSD7AL3 Ignition November 15, 2010 02:14PM
You can get some 20 amp MSD mags for decent money.
I'd go with 44 amp MSD's myself.
And follow Big Jack's advice. "Take the rev chip out, place it on a steel work bench, then smash it with a hammer"
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Re: Having trouble with MSD7AL3 Ignition November 15, 2010 03:11PM
Hey asker, I like the way you think! Thanks for the advice.
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Re: Having trouble with MSD7AL3 Ignition August 27, 2011 05:20AM
have a 7al3 car is leaving like a pig normally 1.23 short time now 1.31 car will not go over 6500 rpm at big end stops pulling timing at 34 degrees leaving at 4400 rpm and shifting at 7200 car normally runs 8.50s now 9.11 stops pulling at about 750 to 800 fet out can msd be retarding timing causing this heard msd 7al3 has had problems with retard system
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Re: Having trouble with MSD7AL3 Ignition November 15, 2010 02:15PM
Call MSD befor you send it, or they will charge you a extra 27.00 for not having a service repair#.
Have heard a lot of bad about 7AL3. 7AL2 or 8 seem to work better.
MACK
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Re: Having trouble with MSD7AL3 Ignition November 15, 2010 04:00PM
Are you using the small or large cap? The small caps are more prone to misfire.

Bret
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Re: Having trouble with MSD7AL3 Ignition November 15, 2010 11:57PM
The 7al-3 box will provide plenty of ignition for your requirements. I have been running one for years on a 16.5-1 648 without issues, we also use a 16 volt battery setup without problems. A few things to cheack as stated above, plug wires and cap, make sure your pickup is not bad, also check your ground and primary power wire. Also not sure if you are using any of the rpm activated switches, or the retard functions but you may want to replace the chips in those positions as well.
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Re: Having trouble with MSD7AL3 Ignition November 16, 2010 02:13PM
One other thing to try i have had trouble with my 7al 2 box msd told me to put on a ground wire from the box and that fixed my problem
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Re: Having trouble with MSD7AL3 Ignition August 28, 2011 12:19AM
Take power and ground directly from battery. Make sure your trigger wire is away from all power and plug wires. Do not even lay the trigger wire on a electric water pump. A tach can also cause this so unhook it and make a run.If not send your box to msd and they will say there was nothing wrong with it but it will work fine when you get it back.
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Re: Having trouble with MSD7AL3 Ignition August 28, 2011 10:53AM
Throw it in trash! go to a Mag set up. We run MSD 44 but there not bullet proof. the generators must be serviced every 20 passes. points box & coil must keep dry and cycled out every 20 passes.
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Re: Having trouble with MSD7AL3 Ignition August 28, 2011 11:28AM
Why would you want a mag if you have to go through all of that. Put a msd 8 on and go pulling for years and years.
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Re: Having trouble with MSD7AL3 Ignition September 05, 2019 08:31PM
my 7al3 will hit the rev limiter at 6700 every time. i've tried 3 different 8000 chips. Replaced coil coil wire,, pick up, crank trigger wheel, new shielded pickup wire, regrounded motor,each head regrounded, rephased dist, new cap, rotor. Put in all new zero chips new 4300 launch chip, new 5 deg start retard chip. Car ran great for 3 yrs, first time out this year it started missing. Been chasing problem all year. Box is now back at msd. They said they new to recalibrate box. thinking of just buying new 7al2plus box. Been to the races 8 times thisyear, 1 run, load up come home. Not fun anymore.
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