Another MSD problem

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rlk340

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Went out to start the Duster this morning to clean it up for a local show. Cranks,no fire. Plenty of fuel, pulled the coil,no spark. When I first put the msd on almost a year ago I had this same problem. I redid the main ground & she fired up & has been running great since then untill this morning. I redid the ground again(moved it to different location)still no fire, tried a different ballast resistor, no change. Tested the msd box for spark according to their instructions & it puts out a healthy spark out of the coil wire but when I hook everything back up no spark out of the coil. I drove her last weekend to the store & back with no problems. I checked the ballast & the switched red with a test light & I have power there but no power to the + coil when cranking the motor. When I first put the msd in I tried to wire it in without the ballast but it wouldn't run with out it. The msd unit is one of Mopar's versions(black housing with MP stickers) that a coworker got for me off e-bay brand new in the box. I'm about to RIP everything out & start over with the old factory conversion kit that was in there
 
MSD ® Ignition Will not start the vehicle:

You will want to start with the Basics on your MSD ® Ignition not wanting to run. Make sure you have a solid +12vdc & Ground to your MSD ® Ignition check all connection points! Check the small Red wire coming out of the MSD ® Ignition box for breakage and poor connection at the switched +12vdc source. Make sure the+12vdc being supplied is not drifting around on your MSD ® Ignition, this will cause your unit to do dumb things. We have seem happen in some variation to many customers when it comes and goes without warning. Remember if the voltage gets below the +10 volt range the MSD ® Ignition box will shut down period.

Don,t know much about MSD, however found this troubleshooting site with (8) pages of ideas on problem topics. (can't hurt for starters) :thumblef:

http://www.msdignition.com/forum/archive/index.php/f-8.html
 
If you have spark with the key on "run" position, but not "start" position, you may want to look at your ignition switch or the connectors from it. The "start" postiion bypasses the ballast resistor, and has it's own wiring from the switch.
 
moper said:
If you have spark with the key on "run" position, but not "start" position, you may want to look at your ignition switch or the connectors from it. The "start" postiion bypasses the ballast resistor, and has it's own wiring from the switch.
Click to expand...

Your right moper, I forgot about the Ign switch prior to the MSD :thumblef:

Added help, If needed (pic) below shows wires from ign with regular electroic system.

scan (Small).jpg


scan0004 (Small).jpg
 
Well I called MSD's tech line today & explained my problem & the tech is leaning towards the pick up in the distrubutor as being the problem. Also he said to get rid of the ballast because it robs the MSD of juice. When I got home from work I pulled the distrubutor & the reluctor has nicks in it & the pick up had some black goo under it. I found that the thick blue wire coming from the ign switch under the dash has 12v in the run & start postion only so I'll tap into that for the red switched wire on the MSD unit. I might look into a MSD distrubutor to replace the one I have now. Jegs has them for around $215 with shipping.I've had the factory conversion kit in my car for over 10 years with plenty of 6500rpm+ blasts so upgrading to the MSD might not be a bad idea.
 
I cant recall, my directions are not near me..but I think I used the feed side of the ballast resistor as the "power on" wire for the MSD. The coil gets juice right from the MSD box, and the box gets juice fromt he (+)POS wire that runs to the battery terminal..The resistor doesnt do anything, as far as I remember once the MSD is wired...If someone has the schematic, feel free to correct me..I haven wired one in a couple years..
 
Yeah, where it says "connect to coil positive.." The output fro the ballast resistor is coil positive..If you use the input side of the resitor, you get battery voltage to the MSD..not a boost, but not a problem either. The 12V is only to tell the box the car should be running.
 
Well I ordered & got the MSD pro billet distrubutor,came in on Thursday. Went out & installed today, got her running & took out for test drive,runs great,But I still cant get her to run with out the ballast hooked up. I retested the blue wire from the ign switch & its only hot in the run position. Tried hooking up to input of the ballast but same thing only hot in run, the out put of the ballast only hot in the start position. Am I over looking something obivous(sp)? I want to get rid of the ballast but for some reason cant find a wire thats hot in the run & start postion.
 
I came accross the same thing on saturday night, and have
been scratching my head ever since.
I fed the msd off the input side of the ballast and it wouldnt start even though there was power going to the box. But when I plug the ballast back in it starts right up
(the power feed still connected to the input terminal on the ballast)
Is it because the charging circuit runs through the ballast?

Moper, are you saying it doesn't matter if the voltage drops on that particular wire??
 
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