12 volt source for MSD/Streetfire

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swanny1911
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Location: Idaho

12 volt source for MSD/Streetfire

Post by swanny1911 »

I recently installed a Streetfire ignition box (made by MSD and same setup instructions) on my 88 grand Wagoneer. Per the instructions I attached the small red wire to the wire that went to the positive on the coil. This wire gets power from the starter relay. When I start the engine it runs. When I turn off the ignition and put the keys on the dash it keeps running.

I read through forums for awhile and read that the MSD/ Streetfire box should not be connected to the starter relay. Whew! Long story short! What specific switched 12v source have others with an MSD ignition box tied into. I'm terrible with electrical systems!!! A coloring book option describing what 12v you used might be necessary! Ha ha! Ooh! I also have the TFI upgrade.
1988 Grand Wagoneer, AMC 360, Streetfire ignition, TFI, 2" body lift, Holley Sniper, Stainless Brain Fabrication Fuel Tank, Evil Twin Fab spare tire carrier. :fsj:
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ClovisMan
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Re: 12 volt source for MSD/Streetfire

Post by ClovisMan »

I put a 6 circuit fuse clock on the fenderwell and ran the 12v switched from a big purple wire under the dash.
88 Grand Wagoneer - The Money Pit - 360/727/NP208 - SOA/SF - Lots of other stuff SOLD
78 Cherokee Chief - Copper - 360/TH400/Quadratrac - 4 inch BDS lift - 33 inch tires SOLD

FSJ Guy
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Re: 12 volt source for MSD/Streetfire

Post by FSJ Guy »

You need to find a switched power supply that is hot during the crank AND run positions.

Sometimes the radio signal is hot during crank and run. You can run a relay off this signal.
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babywag
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Re: 12 volt source for MSD/Streetfire

Post by babywag »

swanny1911 wrote:When I turn off the ignition and put the keys on the dash it keeps running.
Common issue with certain aftermarket ignitions.
If you bought it new, comes with a diode in parts bag that needs to be wired into alternator skinny wire on 2-wire alternator plug to prevent this exact issue.
Instructions are on their website, and diodes available from Radio Shack if you need one.

The duraspark 2-wire connector from firewall main connector one wire is green the other is yellow.
Yellow is the one you want IIRC for 12v supply to MSD box...
-Tony
'88 GW (aka Babywag)
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swanny1911
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Location: Idaho

Re: 12 volt source for MSD/Streetfire

Post by swanny1911 »

Thank you all for the replies! It is already hooked up to the yellow wire from the duraspark. I will plug in the diode then and give that a whirl.


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1988 Grand Wagoneer, AMC 360, Streetfire ignition, TFI, 2" body lift, Holley Sniper, Stainless Brain Fabrication Fuel Tank, Evil Twin Fab spare tire carrier. :fsj:
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swanny1911
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Joined: Fri Aug 12, 2016 4:13 pm
Location: Idaho

Re: 12 volt source for MSD/Streetfire

Post by swanny1911 »

I tried the diode and now it won't start. The skinny wire is a little crispy so it may have broke somewhere. Should be fun to replace with a new diode.


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1988 Grand Wagoneer, AMC 360, Streetfire ignition, TFI, 2" body lift, Holley Sniper, Stainless Brain Fabrication Fuel Tank, Evil Twin Fab spare tire carrier. :fsj:
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babywag
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Re: 12 volt source for MSD/Streetfire

Post by babywag »

swanny1911 wrote:I tried the diode and now it won't start. The skinny wire is a little crispy so it may have broke somewhere. Should be fun to replace with a new diode.


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The diode shouldn't effect starting in any way. It is installed to resolve the engine run-on when key is turned off issue.
It is crimped to small wire on alternator plug to prevent back feeding of voltage that keeps ignition circuit energized.
-Tony
'88 GW (aka Babywag)
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swanny1911
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Location: Idaho

12 volt source for MSD/Streetfire

Post by swanny1911 »

I may have to do more poking around then. It started fine until I tried to install the diode. Now it will barely fire. Might be something in the distributor. Should went HEI lol


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1988 Grand Wagoneer, AMC 360, Streetfire ignition, TFI, 2" body lift, Holley Sniper, Stainless Brain Fabrication Fuel Tank, Evil Twin Fab spare tire carrier. :fsj:
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Topic author
swanny1911
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Joined: Fri Aug 12, 2016 4:13 pm
Location: Idaho

12 volt source for MSD/Streetfire

Post by swanny1911 »

It was the magnetic pickup wire. Replaced it along with an adapter that plugged into the distributor. Now it's running again. Off to carb tuning 101 guess!


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1988 Grand Wagoneer, AMC 360, Streetfire ignition, TFI, 2" body lift, Holley Sniper, Stainless Brain Fabrication Fuel Tank, Evil Twin Fab spare tire carrier. :fsj:
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