Losing Faith

[SledgehammerX]

Slapped a working coil in there and still no fire.

[Zed Head]

I just hit my coil with the multimeter, with the key in the on position since I can't turn it over since I am alone. I put both ends of the multimeter on each the positive and the negative on the coil and got a 0.02 a 0.04 reading.. Now what? A new coil again?

Put the positive probe of the multimeter on the + terminal of the coil,and the negative probe of the multimeter to ground (the engine block or manifold). If you get about 12 volts that means you have power to the coil and a charged battery.

Then put the positive probe on the - terminal of the coil and the negative probe to ground. You should get ~ 12 volts. This means that your coil is probably okay.

Then you'll know that you have power to the coil and through the coil. If so, you can move on to figuring out why it doesn't fire.

jmortensen has a good observation about the module. Personally, I have only had two go bad, one just died completely while driving down the road (1972 Dodge Dart Sport - after a bad voltage regulator did damage) and the other started cutting out at high rpm (1976 280Z after a bad internally regulated alternator voltage regulator did damage). Have you had voltage regulator problems lately, or has your voltmeter been sitting at the high end of the gauge?

[FastWoman]

Sledge, all good advice above. Just a minor note, though: Don't touch the (-) terminal of your coil with your multimeter when the engine is either cranking or running, or you'll possibly lose your multimeter. (It depends on the multimeter, though.)

[cozye]

you wont measure a voltage across the coil, it's very low resistance. As mentioned above you will measure from + to chassis ground, this only verifies that your coil is getting power.

If you were refering to my previous post though about the pickup coil, thats in the distributor. not the ignition coil.

I would go through the ignition section of the FSM and test everything. That will take the guess work out of it.

[SledgehammerX]

Hey Zed Head, I did te test, first reading from positive terminal was 11.25. Second reading was 11.35.... What does this mean?

[cozye]

it means you have power to your coil.

Start on page EE24 of the FSM and test ignition componenets

FSM can be downloaded here http://www.xenons30.com/reference.html

[Zed Head]

It means that your coil is probably good, and if the engine turns over, it should supply a spark, if the module lets it. The ignition module is looking more suspect. The pickup coil is easy to check though, I would do that next. ~720 ohms across the red and green wires to the distributor, disconnected at the junction.

If the pickup coil checks out, and it worked before and you're sure that all of the wires are connected the same as before, then signs are pointing to a bad module as jm suggested. The modules are kind of sensitive and can just die, especially after 33 years. No offense, but the Chrysler or GM HEI module swap might be difficult for you, they are easy to destroy if you make a mistake in wiring.

There are several tests that you can do at the ignition module, on the wiring harness, to check your wiring and components at the same time. It's all described in the Engine Electrical section of the FSM.

75, 76 and 77 modules are similar and you could probably wire one of those in without too much trouble, just match wire colors (you'll have extra terminals on the 76). A 78 would work but you'll need to splice in to the plug, they went from screws to plug-in. Match wire colors again.

Ignition problems are tough...

[spitz17]

Keep the Z faith! I know what you are going through... it's mind boggling and stressful. But I am sure the members here will get you solved!

[SledgehammerX]

So do I take the wires out of the junction box and then put them on the multimeter? I replaced the pick up coil and the ICM, that's why theres a list of new parts at the top that's what all I replaced. Can someone find me a pic of there wiring on there ignition control module to make sure I set up the wiring correctly and to verify I didn't flip them?

[FastWoman]

See post #18. Coz gave you a link to the free, downloadable factory service manual. You'll find all the necessary diagrams there.

BTW, just because you replaced a part doesn't necessarily mean it's good. Sometimes (albeit infrequently) it might be bad.

Edited December 14, 2010 by FastWoman

[SledgehammerX]

Ok so, I already have the FSM on my pc. I have no Internet so I'm using my iPhone. Upon looking at the FSM, it lists 6 wires to be plugged up on the ICM. I only have five. It states this G,R,L,BW,BW,B. I have a green, red, black, black with white stripe, and blue. So I'm a little confused

[FastWoman]

Color codes keys are at the lower right of the diagram. For instance, I think "L" is blue, but I can't remember for sure.