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Thu Jul 10, 2008 12:28 pm

hi samba peoples it my first post love the site.
started a rebuild on a 2276 a bout a year ago . got it running with all your help. ive had a problem with my msd ignition keeps running after i turn the key off. so i would just run to the back of th car and unhook the wires to the msd dizzy. now the car would somtimes shut off with the key. only if the engine was hot. now the real problem. is i took the car for its first real ride 20 miles round trip. got to my destination no problem. got back with the oil temp guaGE just hitting 220. well i had a piece of hose proping the engine lid
open and i lost it an the way back. so that was the main difference on the oil temps there vs. my return trip. so i let the car sit two days. went to start it and now go. no powere to my msd coil. checked my ground seems good. i have fan grounded to the same spot as the msd 6al box and it works fine. ignition switch is good. oil and generater lights on and swich power going into the msd box good. do you think unpluging the dizzy while the cars runnin would hurt the box? i did not unplug it like that the last time it ran, it was hot so it shut off with the key. im gonna recheck my ground. i dont see any fuses on the thing to check. any ideas? :?

Thu Jul 10, 2008 12:41 pm

you need to install a 100v/1a diode on the small wire to your alternator. it should have come with your msd box or raido shack

Thu Jul 10, 2008 2:02 pm

your problem is your electric fan, when you shut off the ignition the fan coasting down is supplying enough power to power the ignition. chances are if you waited a minute the fan would slow down enough and it would shut off on it's own.

Thu Jul 10, 2008 2:34 pm

I have the same ignition & there is a delay when shutting the car off. It doesnt do it all the time but randomly I have to wait for the engine to shut off before exiting my vehicle.

Thu Jul 10, 2008 4:03 pm

okay that makes sence . any idea why it wont start? i aint got power to the coil at the moment. it seems the msd has power ,ground and switch power.
its all soldered in. anybody just have a msd box randomly go bad? is there any way to check it? ive had the msd 6al in the car with no problems for 3 years.

Thu Jul 10, 2008 9:32 pm

Actually, I think that MSD boxes are kinda known for randomly going bad.

Fri Jul 11, 2008 8:00 am

Yes the box will fail. But i would be checking you key on source (little red wire) for 12 volts, also check your points, ignitor, or pickup. Whatever you do dont try to get a reading at the coil! the tool you are using will get fried if the msd sends a signal to the coil. You can also try pulling the coil wire off the dist, and placing it near a ground, now turn the key on and tap the white wire from the msd box against a ground to check for spark.

Sun Jul 13, 2008 10:18 am

thanx 4 the info. ill try that with the white wire. i got power at the key on switch. grounds good.

Sun Jul 13, 2008 11:19 am

tested the white wire and i got spark from the coil :D
sothe box is good, right?. im not to sure what to check next? im stumped.
question, with the key in the on posision should i have power to the posative post of the coil. or thats not the case with the msd setup?

Sun Jul 13, 2008 1:59 pm

DONT PUT ANYTHING ON THE COIL!!!!! testers or meters, they will smoke.
if you got spark with the white wire the box is good :D what dist do you have? if msd check the connectors i have seen these not make contact

Sun Jul 13, 2008 3:10 pm

buggofast wrote: your problem is your electric fan, when you shut off the ignition the fan coasting down is supplying enough power to power the ignition. chances are if you waited a minute the fan would slow down enough and it would shut off on it's own.

If fan is wired to a control relay so fan shuts off when IGN shuts off, this situation can not happen....

Also believe "anti run on" diode on alternator D+ lead may be needed..........

Dale

Sun Jul 13, 2008 3:51 pm

the conectors on the msd distributor? like the plug with the two wires or somthing under the cap?

Sun Jul 13, 2008 4:06 pm

phoenixragtop wrote: you need to install a 100v/1a diode on the small wire to your alternator. it should have come with your msd box or raido shack

X2

Check this Trouble-shooting page out

Sun Jul 13, 2008 4:11 pm

so i checked it out and the connection wire plug two the distributor looks good . i opened it up and seen one of the wires was partially stripped so i taped it up. i dont think that was the problem though. the thing is mostly plastic so i dont think it could have grounded out or any thing. by the way what gap should i have my spark plugs at?

Sun Jul 13, 2008 4:12 pm

Around .030 with the msd

Mon Jul 14, 2008 6:23 pm

If you are using factory type ignition wires with the resistors in the spark plug connectors, or carbon core ignition wire, or have a resistor in your rotor such as the ones Bosch uses, or are using resistor spark plugs, there is a substantial voltage drop between the ignition coil and the spark plug, and you may need to reduce your spark plug gaps by as much as 0.005" to compensate for the losses.

If you are using low loss spiral wound magnetic suppression wire with a resistorless rotor, and non-resistor spark plugs, the maximum size of your spark plug gap is usually limited by the spacings between the terminals inside your distributor cap.

The wider the spacings between the terminals and the wider the distance between the terminals and the distributor body, the larger your spark plug gaps can be before you have crossfiring or arcing to the distributor body causing a misfire. The spark plug gap and fuel mixture density limits the maximum voltage that the distributor cap and the ignition wires will see.

The ionization voltage, or arc-over voltage of the spark plug gap is primarily dependent upon the number of molecules of fuel mixture between the electrodes of the spark plug gap. So a wider spark plug gap with more molecules between the electrodes requires a higher voltage to jump the gap.

The fuel mixture density will affect the number of molecules in the spark plug gap. The higher the fuel mixture density, the more molecules between the electrodes of the spark plug gap and the higher the voltage required to jump the spark plug gap.

Anything that you do that raises the fuel mixture density, such as a higher compression ratio, a cooler heat range spark plug, firing the spark plugs closer to top dead center, or raising the volumetric efficiency through porting, larger carbs, camshaft, increased valve lift, turbocharging, a more efficient exhaust system, reducing the temperature of your fuel mixture, and higher barometric temperature, will cause the ionization voltage of your spark plug gap to be higher.

As you can see, there are many factors that affect your maximum spark plug gap, including the capability of your ignition system. The stock Bosch ignition coil loses output voltage as the RPM increases. With a stock engine, you need to limit the spark plug gaps to about 0.025" to be able to fire the spark plugs at maximum RPM.

As your MSD is a higher energy ignition system, you could use much larger spark plug gaps. Your main limitation on the size of your spark plug gaps is likely to be the spacings inside your distributor cap which will determine the maximum voltage that it can withstand before crossfiring or arc-over to the distributor body.

With a near stock engine with a 7:1 compression ratio you could probably use 0.060" spark plug gaps. With an 8:1 compression ratio with larger carbs you might be able to use 0.050" spark plug gaps.

Every engine is different. The only way to know the optimum spark plug gap is to increase your spark plug gaps about 0.005" at a time and try it. As you increase your spark plug gaps, your performance will improve to a point and then get worse as the spark plug gaps become larger. When the performance degrades, then reduce your spark plugs gaps to the largest gaps that your engine was working well.

Also, if you are using a high energy ignition system, you can usually use a spark plug with one or two heat ranges colder and still fire your spark plugs. This will reduce the possibility of pre-ignition or run on.

You will get the most horsepower out of your engine by using standard non-resistor copper core spark plug. Special electrode, fine wire electrode and precious metal electrode spark plugs will only improve a weak ignition system by reducing the ionization voltage of the spark plug gap.

I use 0.065" spark plug gaps with a small cap Mallory distributor, and a Jacobs ignition system, but I also have a very low 6.8:1 compression ratio. I use NGK BP7HS10 spark plugs without any fouling problems.

Scott Novak

Thu Jul 17, 2008 12:07 am

hahahhaha yeah i found stepping on the brake helps i dont know why
nothing else does it not the head lights not the turn signals
nothing except the brake
uh owell :D

Thu Jul 17, 2008 7:39 am

bigbadben wrote: hahahhaha yeah i found stepping on the brake helps i dont know why
nothing else does it not the head lights not the turn signals
nothing except the brake
uh owell :D

Thats cause you gotta stop all them hamsters in there :D

Thu Jul 17, 2008 1:27 pm

still not gettin spark...the box sparks when testing with white wire.( points)
but when i test for spark with the two pin magnetic pickup no spark. so i guess somthing with the magnetic pick up is fried.

Thu Jul 17, 2008 5:59 pm

If you short the two wires going to dist (for magnetic pickup), it should produce a spark, think this is is laid out in MSD installation/test/trouble shoot documents... If it will spark this way, I think unit in dist is probably fired, or wired wrong...

What type/style/brans sidt are you using..

Also be sure white wire is insulated when using magmatic pickup wiring... IF white wire is grounded when using magnetic pickup, it kills MSD box and acts as anti-theft device.

Dale