All,
My 71 Cutlass has a very weak spark. I just replaced the points, coil, and cap. I ohm'd my wires and they are fine as well. What happens is that when I crank it I have my spark tester set to a quarter centimeter gap and it sparks weakly most of the time, then sometimes it doesn't spark at all. If I hook my tester directly to the coil it sparks every time, but it still is a weak spark. I tested this same tester on my 73 Continental Coupe with a 460 and I can make the gap 2 centimeters and it still sparks.

I am doing all this testing because my car won't start. Ran fine but was backfiring out the exhaust when cold. Progressively started getting worse so I replaced the points and now she won't start. Turns over but never catches.

I'll post a video later so you can see what I'm talking about

 

Whats your dwell setting???? Should be 30.

 

Dwell, dirty points (on the shelf too long), bad starter-motor-to-coil connection, bad "R" terminal inside the starter solenoid, or... bad condenser.

- Eric

 

Right at 30. I also am getting 12v to the coil. Only thing I can think of is maybe one of the ground straps is coming loose on the engine (Anyone know the locations on a 71 Cutlass? :-)

Other than that if I have my tester connected right to the secondary output on the coil (To eliminate the cap, rotor, or wires being bad), and I am getting 12v at the + terminal on the coil, then I should have a good spark, strong enough to shoot at least one centimeter (Right? lol) in my tester? The tester's electrode is at the zero mark. If I put the other end of the electrode at the first line up from 0 it gives me a weak spark. But if I put it at the second line up from zero NO SPARK.

I also replaced the condensor as part of the new points (They came with it and the condensor is under the cap right?) I also connected a test light to the - terminal on the coil and it went on and off which tells me the points are opening and closing correctly right? Thanks,

 

Check.
Check.
Shouldn't be the problem - the battery negative cable should be going right to the block.

Even when cranking?

I'd say so.

Aha! Having been utterly baffled twice (the first time for days on a new engine rebuild) by brand-new bad condensers, I would consider swapping in a different one.

That should be the case - if you get enough juice through the points to light a decent test light brightly (a tallight lamp, for instance), they should be clean enough to run.

- Eric

 

Do you think possibly some grease got into your points?

What if you run a jumper wire directly to your coil from the battery. Please note, that if it does start, that wire would have to be removed to turn it off.

If that does not do it I would suggest like above, another set of points and condensor. IF not that, then I would likely swap in a known good coil.

 

Why not put an HEI distributor in it..??

 

'Cause he doesn't have one in his toolbox .

- Eric

 

LOL - Some of us do llike points!

 

I like points, but I don't think I have a really strong opinion on the question -
I've never had a points failure that caused the car to just stop running, or that wasn't fixable with a screwdriver or an allen key on the side of the road within five minutes.

HEI does make a hotter spark, and doesn't change its adjustment as the rubbing block wears, but I've had two electronic ignitions fail on me in the past, both killing the motor without warning while driving. If I could carry a full set of spare parts for a reasonable price, I'd feel more comfortable with HEI, but the parts aren't cheap like a set of points and a condenser are.

- Eric

 

I changed my 71 over many years ago and it has never given me a moments trouble...I once had a 64 Cutlass 330 car and changed it to HEI as well..

 

How do you know the dwell is 30 degrees if it won't run? What clearance did you set the points to, somewhere around .015-.018 should at least let it run. Disconnect the condenser, it will still run, if it still won't start I would get a new coil, and make sure it's not reversed.

 

You can set the dwell while cranking the motor. It doesn't change with engine speed like the timing does (though modern computerized systems DO vary the dwell with engine speed to optimize coil saturation and cooling).

- Eric

 

Exactly how I did it. I have a new coil too so it's not the coil. I haven't had a chance to mess with it since my original post. Soon as I get back out there Ill let you all know what I discover. I'll try to make a movie this time so you all can see what I'm talking bout

 

Did this issue arise with the coil swap? I know that some GM coils have a resistor built into them, just wondering.

 

Naw it started when I replaced the points. Hasn't started since

 

Well I would do the jumper wire from battery to other side of coil thing as I mentioned above, that pretty much elinates everything in the run /start circuits and leaves only items from the coil to the dist.

I recently also had a major problem with a set of points and condensor. Try putting your old points back in and see what happens.