When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Looking for some advice/suggestions. Last weekend my boys swapped out the engine in my 72 Cutlass with another 350 (used roughly 60K with new seals, gaskets, timing chain) as the original was just worn out. Do to a recent hospital stay my abilities to get my hands dirty are not what they used to be so I wasn't able to monitor the job the way that I would've liked to but nonetheless they got it in. I'm running a quadrajet with the points distributor, swapped out all of the ignition parts from the running motor. They had a bit of trouble getting the starter in (they were uncertain if the purple and yellow wire were on the right spots on the solenoid) and on our first crank there was a big spark/arc where the starter touched the heat shield on the exhaust manifold. Dropped the starter, adjusted the shield and attempted to start again. It cranks really strong but no spark. Double checked the distributor location and it is pointed at cylinder #1 at TDC. Even swapped out the coil, condenser, cap, rotor and points with another set and still nothing. At one point during cranking I advanced the distributor and it backfired through the carb but the test light still showed no spark. Is there anything that they may not have connected during the swap? I will begin some testing but I have to take my time and not over do it for myself. Is there anything that could have been "burned up" during the starter issue? I was on the fence with installing an HEI which I have, should I eliminate the diagnosis of the points and just install the HEI? I would consider myself just above novice, so some of this stuff may get beyond my level of experience and I may have to source this one out, just trying to eliminate a few things here to see if I can handle it myself.
A points ignition is a lot easier to troubleshoot. Than a HEl. There is a resistor bypass wire that goes from the starter or to the coil (on stock setups).
A points ignition is a lot easier to troubleshoot. Than a HEl. There is a resistor bypass wire that goes from the starter or to the coil (on stock setups).
Correct, the one that comes from the starter. Is it possible this could have been damaged during our starter issue?
Ensure you have the wires hooked up correctly to the ignition coil. Yellow wire from starter & resistance wire are connected to the ignition coil (+) terminal. Wire from distributor is connected to ignition coil (-) negative terminal. You should have 12V at the ignition coil (+) terminal with key ON.
Ensure you have the wires hooked up correctly to the ignition coil. Yellow wire from starter & resistance wire are connected to the ignition coil (+) terminal. Wire from distributor is connected to ignition coil (-) negative terminal. You should have 12V at the ignition coil (+) terminal with key ON.
Wires are connected in that fashion. My initial check I did not have 12 volts at the coil. Just to be sure I'm testing properly, should I remove the wires to test or test them connected to the coil? Sorry for such a basic question just making sure I'm doing it correctly. Thanks!
No, you don't need to remove the wires. I generally will remove the high tower (ignition coil wire) before testing (+) terminal on ignition coil. You only want to measure voltage to that (+) terminal. One DMM probe to ground one DMM probe to (+) ignition coil terminal with key in the ON/START position. You should have voltage to the (+) terminal.
It should be obvious, but to make the point, if you don't have voltage to the ignition coil (+) terminal, you'll have no voltage to the ignition coil high tower ignition coil wire to the distributor. If no voltage to the ignition coil (+) terminal, the issue resides prior to the the ignition coil (+) terminal.
It should be obvious, but to make the point, if you don't have voltage to the ignition coil (+) terminal, you'll have no voltage to the ignition coil high tower ignition coil wire to the distributor. If no voltage to the ignition coil (+) terminal, the issue resides prior to the the ignition coil (+) terminal.
Norm, I just checked for power at the coil and with the key on I have 11.98v at the + on the coil and 11.89v at the coil tower lead to distributor. I have tried with another distributor along with other points, cap, and rotor and still no spark at the plugs. I've read stories of being 180 out...could this be the case? When I set the distributor I used the timing marker but also double checked and can see that the #1 piston is TDC. I probably won't go back out until tomorrow but wanted to give you my findings. I appreciate you taking the time to help! Mike
Norm, I just checked for power at the coil and with the key on I have 11.98v at the + on the coil and 11.89v at the coil tower lead to distributor. I have tried with another distributor along with other points, cap, and rotor and still no spark at the plugs. I've read stories of being 180 out...could this be the case? When I set the distributor I used the timing marker but also double checked and can see that the #1 piston is TDC. I probably won't go back out until tomorrow but wanted to give you my findings. I appreciate you taking the time to help! Mike
Measuring voltage on the ignition coil high tower is inconsequential. Voltage comes into the ignition coil ~12V and exists the ignition coil far, far greater than 12V when the ignition coil is energized (e.g. operating). Bottom line is you have 12V going into the coil. You stated you have no spark out. Did you attempt to measure spark and how did you measure spark? This will be more or less key to furthering the troubleshooting. Regarding 180° out on the distributor means the spark plug will try to ignite when the first cylinder is coming up for the exhaust stroke rather than coming up for the compression stroke. In such a scenario you'll still have spark, but at the incorrect time. I think you're on the correct track of establishing if you do, in fact, have a spark from the ignition coil to/through the distributor and to the spark plugs. Obviously, no spark = no start.
I'm going to provide a link you can read - I have several time commitments. I suggest you review my posts (in particular) as well as others regarding the establishment of whether you do in fact have any spark. My posts provide a little more detail on troubleshooting the ignition coil when measuring its resistance. It would not be unheard of that your coil took a beating when you grounded out your starter, but the issue could still be elsewhere - others will surely chime in.
So after reading multiple things I wanted to confirm my TDC with the paper towel method and confirmed that it was not at the 0 on the timing marker, more like at about 16 degrees. So I reset the distributor and attempted to start, still no spark. I have an inline spark tester and connected it to the coil and I have nothing coming from the coil. Swapped multiple parts with known good parts including coil, wires, cap, rotor, points and even distributor and still nothing. Double checked the ground wire from the firewall to the cylinder head as well. My guess (I hate to take guesses but I truly am a novice for this level of work) is that some wiring in this 50 year old vehicle was disturbed during the swap. I followed a few of the recommendations in other threads and it would seem as maybe one of the wires in the distributor could be bad however they look good and that would be on 2 different distributors. Any thoughts with this information is welcome and appreciated. I'm not one for throwing in the towel but do I continue to chase this demon or just wire in the HEI?
You validated you have 12V going into the coil and no volts (spark) coming from the coil. If the ground wire from the distributor has continuity to the ignition coil, your ignition coil is DOA. Test its resistance to validate.
With my multimeter set at 200 ohms primary is 28.8 but keeps jumping, secondary set at 20K is 10.4. It's a cheap Harbor Freight meter so hopefully these are good numbers.
Last edited by 72 Post; April 30th, 2023 at 06:56 PM.
Reason: additional comments
At the back of the ‘Chassis Electrical’ section in your CSM is a GENERAL SPECIFICATIONS chart which demonstrates COIL Primary Resistance and Secondary Resistance. If primary resistance is above 2.0 Ohms the coil is DOA. If secondary resistance is below 6500 Ohms the coil is DOA (basically same numbers I outlined in the link I provided). I’m suspicious of the ignition coil since when the starter was shorted against the shield and there was a large electrical arc - that current may have ran directly into the ignition coil. At which point the insulation between the primary and secondary windings may have collapsed leading to a failed ignition coil. It’s the right place to start evaluation.
Your numbers basically suggest the primary winding has far too much resistance to pass voltage into the secondary winding - most likely the insulation collapsed or the coil itself has shorted internally. The secondary winding resistance is OK but, you cannot get from the primary winding to the secondary winding to increase voltage to supply a spark. Remember, you’re measuring resistance.
I’ll mention it is always beneficial to replace the ignition coil condenser when replacing the ignition coil as that little condenser plays a significant role in properly collapsing the electromagnetic field to ensure a solid field collapse (spark). Good luck!
It’s a good idea to test a newly purchased ignition coil BEFORE you mount it. Nothing mysterious about this, the resistance values MUST fall within the values as stated.
When you turn the ignition switch on you should have positive voltage to the (+) side of the coil. You should have slightly less than 12v with the key on and more than 12v while starting. The distributor points are the switch that turns the negative voltage on and off to the (-) side of the coil. You can simulate this to test the coil by applying 12v to the (+) and rapidly touching ground to the (-). Place the high voltage lead of the coil near a ground source like a clean bolt head and you should see a spark every time you disconnect the (-) side. If that works, the coil is good. Make sure the wire coming out of the distributor to the (-) of the coil is not touching a ground source anywhere except through the properly gapped points. The points must make, and break contact with ground source on the (-) side of the coil to make a spark.
Sounds like you have verified TDC so the timing should be close enough to make the engine at least cough while starting.
Sorry it's been a while since I've updated but I've been down medically. So I did get a new coil and unfortunately that didn't work. At that moment I have to admit I tossed in the towel on the points and installed the HEI. Unfortunately I didn't test everything before installing and after a bit of a struggle still not getting spark I finally figured out that the pickup coil on the 40 + year old GM distributor had given up. Luckily I had a new pickup. Installed it and bam, she fired right up. Looking back, I do believe my impatience got the best of me and the root to the problem with the points distributor I believe is a break in the wire from the points to the coil. Either way she's running and now I just need to adjust the carb and get it timed. I will take some time looking into the other distributors because I do honestly like the idea of the points. Maybe once I get the original motor rebuilt we can go back to points. Thank you all for the help and guidance.
April 28th, 2023, 05:27 PM
