Car done, but no spark... please help

[juvius]

I'm not getting any signal from the ignition coil to the distributor. The car is a 71 with a 2 liter engine and 1800 head. I'm using the ignition system from the 79...

with the key on, i get 12v to the +B side of the coil. I have a good ground on the aluminum base. I had the control module checked at orielly's auto parts and it passed and i replaced the ignition coil. I have even tried two different distributors. I search and search, stared at the electrical diagrams forever... I just can't figure it out...

i am getting a 12v on both terminals of the ignition coil with the key on. is that right? i thought the other side sent the reading to the tachometer....

[seabeelt]

Have you checked the pick up wires from the distrib back to the control module, and also the gap inside the distrib. The wires have a habit of getting caught on something or rubbing the insulation off and then shorting to ground inside the distrib. Check the IAP website for YouTube videos to check for continuity. This is really all that is left in this circuit. Yes the other side of the coil goes to the tach, however, you can read positive voltage on both sides of the coil.
R/

[juvius]

I'm actually out getting another coil and control module. Going step by step with my manual. So far the coil resistance doesn't meet requirements...

[majicwrench]

Coils almost never fail, yet everyone loves to change them......
Start at the begining. Pull cap, watch dist rotor actually spin when cranking.
Have you actually attached a plug to the coil wire to make sure it is not firing??
If not, pull coil wire out of cap, insert plug, rest it on head, crank engine watch for spark.
Or tell some young boy "Here, hang on to this"
Test for power on + side of coil, should be 12volts
Test for power on - side of coil, may show almost anything, module grounds and opens - side.
Got a tach?? Hook lead to - side of coil, crank engine, does it show RPM?
Does dash tach show RPM when cranking??
No RPM signal = module or pu coil bad, shorted or wiring issue tween coil and dist.

[juvius]

i have everything off and sitting in front of me... i'll start putting it back in so i can do what you suggested...

[juvius]

pulled the cap... rotor is spinning when cranking.
No spark out of coil wire
power to + side
power to - side
tach does not move while cranking

i spaced the pickup coil with my .55mm feeler gauge since specs say .5 to .6mm

i don't think my multimeter is working too well... i'm not getting any readings close to what the books say i should be getting.

is it safe to say that since i just put in a new module that i have a bad pick up coil?
the wires on the pickup coil look good and clean.. actually doesn't look very old..

[majicwrench]

What readings are you not getting according to book?? Mulimeter likely fine.

Did you not already try diff distributor?? Is it a known good unit??
Follow coil neg into dist, check for + there were it connects to module.
Take a jumper wire, ground one end. Turn key on. Remove coil wire from dist, and plug in spare plug, lay on head. Recheck for + on coil neg. If you have + on coil neg, now take free end of jumper wire and tap coil neg. Spark should jump spark plug gap.
All the module does is ground/open coil neg. So if you have power at coil neg, and you touch it to ground, you should get spark at coil wire/plug. Let us know.
Keith

[juvius]

thanks keith.. i'll let you know as soon as i can...

i did try another distributor, but i only have one pickup coil to use between the two....

[juvius]

i do get spark when i ground out the negative side of the ignition coil... what does that mean?

[majicwrench]

It means you are narrowing things down in a nice controlled manner. Either your module, pick up or wiring to dist is bad. Did you follow the coil neg wire into the dist and make sure it has + where it connects to the module??

[juvius]

yes i did....

[majicwrench]

Wish I could find a good wiring diagram of ign system, don't have one, dang. Has this system ever run before in this car?? You have module w two terminals on each end, yes?? If so, on same end as coil neg wire attaches, other term on that end should have + with key on, does it? Wires on other end of module should then go to pu, yes??
If so, and you know module to be good, change your PU coil. Methinks I have a complete dist out in shed gonna go look at it.
Keith

[juvius]

keith,

No i haven't had this system running before.... when i bought the car is had a 1438cc engine minus the head... i put a 2 ltr with an 1800 head and intake on. the ignition coil and the other ignition module i have seen work in the 79 before I scrapped it. I'm not sure about the distributor though. I had three all together and mixed them up. i sold one and still have the other two. I do have power everywhere there should be. I have a new pickup coil on the way... so i guess i'm dead in the water til that arrives.. While i have been figuring this out i hooked my little hand pump vacuum gadget to the vacuum advance to see if either was good.. my luck.. both were bad, so now i have to get another one of those... does it ever end?

[majicwrench]

If you have not had this system running...how did you wire this system up to your old harness?? Module needs power at the terminal I indicated. How many wire do you have running to your distributor?? I have no faith that a PU will fix it unless you can confirm that you have the wiring correct.
And all those old vacuum advances are bad.
Have you pondered just putting a points dist back in it??
Keith

[juvius]

wires are correct... reading wire diagrams are one thing that i feel proficient at. I have both the 71 wire diagrams and the 79 wire diagrams. Power comes from pin 15 on the ignition to +B side of the ignition coil. The other side of the ignition coil goes to the tach. I have put an extra ground wire from the chassis to the aluminum heat thangamajobber that the control module and the ignition coil mount to. With the key on, i get power to the +B and the neg side also shows current. then of course the two wires from the control module.. red to the +b side and the other to the neg side.

one thing i just notice... i did the test with the ohm meter that the manual says to try by putting the probes on each wire of the pickup coil and that i should get a reading of about 700 to 800 ohms... when i do this, it starts around 500 and the number slowly works its way up and doesn't stop... i last disconnected an around 950...

no i don't know that much about different types of distributor.. but i just ordered a new vacuum advance to put on it.