proxlamus© Posted January 19, 2007 Share Posted January 19, 2007 Specs - Megasquirt n Spark 2.2pcb 021u code. 83 dizzy, GM HEI and stock igniton coil. Ok.. I was driving down the road.. and all of a sudden the car died. I pulled into a neighboorhood and began some tests.. I have fuel pressure.. the plugs are wet so it is spraying fuel. I pulled the spark plugs.. NO spark. I pulled the spark electrode wire out of the coil.. and since I had no multimeter I cranked it and held onto the electrode, I definatly got one hell of a shock. I assumed it was a cap/rotor. So i replaced the cap and rotor... and no spark! Hmm.. I tested the coil again and there was no spark and no shock Now to source it down... the coil is an original 1978 coil, So i replaced it with a MSD Blaster 2 coil. Car fired right up, drove it home, died in my driveway. No longer ran, and would no start. I am assuming it was the GM HEI setup, so I put in a NEW GM HEI module.. still no start. The problem is, I am not getting any spark out of the coil.. and is not sending any spark to the dizzy. My only other assumption is the DIZZY is bad.. and is not sending a signal to Megasquirt. So I measured the voltage on the GM HEI to see what was going on. (INCLUDED IS A DIAGRAM TO HELP) B (goes to + of the coil) = 12v C (goes to the - of the coil) = 12v W (GM HEI ground) = 0v (obviously its a ground) G (attaches to Megasquirt) >>> [ 1)On initial turn key to ACC, the fuel pump primes, and the voltage is 12v for a few seconds. I am assuming MS is sending an signal to the GM HEI which is why I can sense voltage. 2) In addition I can read 12v while cranking at this terminal. 3) The voltage reads ZERO (0 volts) when the key is on ACC and the ignition is live, untill I crank.] Now.. I have NOT read the voltage from the dizzy to megasquirt since I am getting postive voltage from MS to the GM unit (if the dizzy is bad will this still show a reading?!) The coil reads 12v and is getting power. Could this be a problem with 1) Megasquirt? 2) DIZZY 3)coil wiring ?? Quote Link to comment Share on other sites More sharing options...
mario_82_ZXT Posted January 19, 2007 Share Posted January 19, 2007 Is MS getting an RPM signal? Plug in your PDA or laptop and you should see about ~300rpm while cranking. I'm thinking something probably got knocked loose. Check your connection between MS and the relay board, and the jumper and connections on the relay board itself. Mario Quote Link to comment Share on other sites More sharing options...
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