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HEI distributor no spark???

44K views 18 replies 10 participants last post by  Schurkey 
#1 ·
Have a 70's 327 in my 67 malibu. Wouldn't start tuesday morning, plenty of fuel, no spark. MSD street fire HEI distributor with built in coil. Have 12V to the coil. OHM'd coil, primary (batt wire to tach wire) good, .7 OHM's. Secondary, (batt wire to carbon pick up on bottom of coil was OL. MSD tech line says it's bad, buy a new one it also OHM's bad for secondary but Tech line says it's probably my multimeter. OHM's a 3rd coil at autozone using there meter for all 3, all OL, they say it's very hard to OHM the secondary. still no spark. Had module tested, passed about 10 times. OHM'd magnetic pick up, checked good. I found steps for measuring voltage out of the pickup (should be 3V mine is .5) that tested bad but MSD tech said that it was impossible for me to check voltage there, so my voltage check there is inaccurate. Help anyone.....
Supposed to be 76 degrees here in tacoma (freakish) and I really want to take my son's out in the hot rod.
 
#2 ·
Make sure that the distributor is actually turning by rotating the crank with the cap off. This will eliminate the possibiility of a jumped t-chain or sheared distributor gear roll pin.
If it all looks good, I would swap in another HEI to drive the car and enjoy the weather while you try a another pickup coil or module in the old unit on the bench.
 
#6 ·
Zombie, I increased my distributor knowledge about 7000% percent over the last two days:yes: I would still rather check the smaller/easily replaceable/cheaper parts first.

Wagner, I did remove the coil completely when checking resistance so no button involved and I thought the pickup coil and magnetic pickup were synonimous, if not please direct me and I'll gladly OHM that as well, thanks guys.
 
#7 ·
if you have another HEI it isnt that difficult. mark the one you have where the rotor is facing, dont pull the wires off the cap. Then slowly pull the distributor out and mark it where the rotor turned too. Then mark the second distributor in the same spots, and drop it in in reverse order. Timing it isnt that difficult with a timing light either... personally I would drop another distributor in and work on that out of the car. Otherwise you might be throwing parts and money at it and not getting it fixed.
 
#11 ·
Secondary, (batt wire to carbon pick up on bottom of coil was OL. MSD tech line says it's bad, buy a new one it also OHM's bad for secondary but Tech line says it's probably my multimeter. OHM's a 3rd coil at autozone using there meter for all 3, all OL, they say it's very hard to OHM the secondary.
WRONG PROCEDURE. No wonder there's no continuity. If MSD told you that the coil was bad based on that description...my respect for MSD just dropped a few points.

Done correctly, it is NOT AT ALL difficult to measure secondary resistance.

Measure the secondary on MOST HEI in-cap coils by going from BLACK wire to terminal for carbon button. If you try to measure from batt wire (red) to carbon button--you WILL get an open circuit.












There are a very few in-cap HEI coils that do not have a black wire--they were only used by GM for a very few years--and in the case of those coils, red to carbon button is a valid test procedure to measure secondary resistance.
 
#12 ·
Take off the rotor and flip it over and look at the bottom of the rotor in the center. If there is a small black dot there, the rotor is probably allowing the coil to arc down through the center shaft of the distributor. This is especially true if you are using a high voltage coil. I have had this happen to me several times in my life. Each time, the car ran fine with no problems. I turned it off and it later refused to start. I actually carry a spare rotor in my glove box just because of this.
 
#15 ·
What scale is the meter set to?
 
#14 ·
check the ground strap/wire for the coil. it's under the plastic cap, held by one of the screws that hold the coil and runs to the plug on the side. use a test light to verify that it is getting a good ground. i had a bad connection on that once that caused it to not fire, and even left it off once back when i was 16 and knew everything. good thing my grandpa knew more than me and fixed it in about 20 seconds...
someone already mentioned the tach wire- if that wire grounds out, the coil won't charge up.. that wire is a good place to hide a kill switch, by the way..
i have to assume that you have verified power to he distributor..
check the carbon button that goes between the coil and rotor- if that part breaks, the spark won't get from the coil to the rotor.
 
#16 ·
Tom: I must slow down my reading speed , as I totally missed your mention of the pickup coil. Your ohming of that pickup is the correct way. As for measuring voltage, I believe you would need a peak reading voltmeter to capture the actual voltage. These are common in the outboard motor service shops. So, I suspect your pickup is OK.
 
#19 ·
Plugs fouled?
 
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