Thread: Help ignition

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HHHHHHeeeeeeeeellllllllpppppppp. I have been fighting a one problem after another on wife's car. Its just a sbc 383. I am not getting spark. I have replaced the coil, MSD Blaster, and nothing. Here is what I have done. I checked the coil wire that goes to dist. and get no spark. I brought the new coil to shop and had it checked, good. I measured the voltage to the coil + side to ground and get 12.6v with key on, not cranking. I checked the voltage to center conductor to ground (coil wire) and get 12.6v, not cranking. I do get 12.6v on the negative side of coil to ground with key on, not cranking. I thought that was wrong an maybe it was a direct short. Pulled wires off negative side of coil and don't get any voltage from wires with key on, no short. I have been trying to work towards the distributor thinking it might be the issue. Am I wrong in thinking that there should be no voltage to negative side of coil with key on? Also get no pulse when measuring the voltage between the + and - side of coil, which I thought I should get. Help me in what I'm doing wrong, would appreciate.

what kind of distributor? I've had the magnetic pickup go out in my dist same thing, no spark... replace the pickup good as new.

Do you have an MSD ignition box? You can disconnect the two-wire mag connection to the dist and short with paper clip should give you a spark. If using points dist, disconnect the white wire and tap that to GND and you should get a spark. The coil has low DC resistance and will read 12V on both terminals unless you are pulling one end to GND to "charge" it up... otherwise, you would burn up the coil real quick. Some more info on the rest of the ignition system will help get to the bottom of it.

-Chris

Nothing more frustrating that ignition problems - good news is they can be fixed!

Is this a new build?

Have you run this combination previously?

Why are you using the Blaster? (Ready-to-run distributors do not require an ignition box - see below.)

What type distributer are you running?

When you say coil, is it a standard (old style), MSD, or GM-HEI?

Give us a bit more information and we'll get you fired up in no time!

skids, this is an old style hei. no ignition box. i thought the dist could be issue, but can't get spark from coil, so while dist is still in picture, i've got to get past the coil.

gs, yes its an old style coil, MSD Blaster (P/N 8202), which is an external resistor type. the reason this is being run is that its an old build. the engine has been running before, very well, it was a low 11 second car. this mess started with replacing the starter and went from there. but the coil isn't acting like i think (which don't mean much) it should. i'm confused in the fact that there is current on negative side and i'm not sure there is suppose to be any. once i can get spark on coil wire, then i can work to dist. there is also the issue that as i remember this type of coil should pulse when checked from positive to negative on coil.

let me know anything else that will help you narrow this down. thanks for the replies.

Pop the distributer cap and the rotor off.find the 2 wires that come from the relucter and disconnect them from the ignition module,measure resistance across those 2 wires should 1200 to 1500 ohms if not the reluctor (i.e. pickup) is bad. If it ohms out o.k. replace the module and inspect the cap and rotor.

Originally Posted by HWORRELL

Pop the distributer cap and the rotor off.find the 2 wires that come from the relucter and disconnect them from the ignition module,measure resistance across those 2 wires should 1200 to 1500 ohms if not the reluctor (i.e. pickup) is bad. If it ohms out o.k. replace the module and inspect the cap and rotor.

thanks will try that tomorrow and let you know. cruise nite tonight and at least my car runs.

You are not getting power when it is cranking. Wires wrong at the starter.

Originally Posted by Mikej

You are not getting power when it is cranking. Wires wrong at the starter.

Mike, thanks for the input. Since the starter has been installed the car has started. However, since then something went south. Based on input above, I've got someone that knows distributor coming over to help me. Will keep everyone posted. Thanks again.

Originally Posted by DennyW

Do you have voltage at the coil while cranking ?

Denny, yes I have voltage at coil while cranking.

Originally Posted by DennyW

Ok, when you take the cap off, check the pickup wires. They can be touching ground, or...they can be broken. These wires move all the time during the advance, retard when driving. Very common for these to break, and look good. Give them a Light tug to make sure they are not broken inside the insulation.

denny thanks. will have to wait until tomorrow to work on car. will get back to all with what i find.

I reread your post. If it is an HEI distributor you don't need the resistor. The resistor is for a points type distributor. Bypass it and see if that works.

guys thanks for all the help. it took awhile to track this thing down. the coil was good and so was the distributor. it turns out to be a bad connector on the boost retard system (old stinger type). it was an 8 pin connector that was intermittent. a friend came over and finally help me track it down. bought a new 8 pin connector from summit. again thanks for all the help.