455Jimmy72

Hi so I'm new to this forum thing so bear with me, lol. So I have rebuilt a 455 olds an have put it into my 72 GMC Jimmy. The motor was in it when I got it. I have everything hooked up correctly I believe. Problem is I can't get it to fire. What I'm dealing with is I have power to my coil and power to the distributor but I have no spark coming from the coil which was brand new with the rebuild. Before I condemn a brand new coil I figured I'd hop on here and ask for other thoughts first. Any how thanks for your help and time.

Fun71

What type of distributor do you have? Points, GM HEI, or something else?

455Jimmy72

Points. I would love to install a different type but currently don't have the funds to do so.

Rallye469

So then are the points in good shape and the condenser?

An you can test a coil easily with an multimeter/ammeter.
You’ll be testing the primary and secondary fields for an Ohm range.
-peter

Olds64

I deleted your double post.

Here's an excellent thread on troubleshooting points ignition. I @$$ume your running points ignition.

https://classicoldsmobile.com/forums...gnition-76706/

redoldsman

First thing I would do is check the gap on the points. Then I would try a new condenser. The ones coming out of China (just about all of them) are crap. Good luck.

joe_padavano

^^^THIS! Be sure the points are gapped properly and that the wire from the distributor to the negative side of the coil is not shorted anywhere (a shorted condenser will have the same effect).
The points just open and close the circuit from the coil to ground. If the circuit never opens (ie, shorted wire, shorted coil, or incorrectly gapped points), the magnetic field in the coil never collapses and thus no spark is created.

oletrux

Good grounds?

joe_padavano

If the grounds were bad, the car wouldn't crank. The only "ground" in the ignition system is the wire to the points, which we talked about already.

oletrux

Yeah, brain fart. Sorry to interfere.