72 Convertible 302 No Spark When Starting
05-22-2017, 09:02 PM
#1
Thread Starter
Join Date: May 2017
Location: Washington
Posts: 4
72 Convertible 302 No Spark When Starting
Hey all, I'm new here. So I have a 72 302 that has been sitting for 16 years. That will not start. I checked for a spark and there is none. I've replaced the distributor rotor and cap along with the ignition coil and still do not have a spark. When I turn the key, starter does its job but I don't get a spark. I haven't replaced the plugs or wires. No matter what plug/wire I try with my test light they dont spark.
So a history about it. From what I know that is. This was bought brand new by my grandfather we worked for IBM in sales im guessing. (He knows the basics of an engine) it was his daily driver for almost 10 years till he basically totaled it. For 2 years it sat getting a rebuild and when it was finished it came out with basically everything up front, before the dash brand new. Engine,radiator,bumper,quarter panels,etc. Now the engine I believe is another 302 pulled from another mustang and rebuilt. no one knows except my grandfathers mechanic which happened to take it to his grave a few years back. My father (knows a fair amount about cars) then started driving it and kept it garaged. One day we where moving into a new house so he had to move it. I was a toddler so I wasn't all there to see what happened but apparently he was just backing it into the driveway when it suddenly died on him he was unable to start it back up so he pushed it into the garage and never touched it again. Until I had the idea to get her working again.
Any input would be amazing Thanks in Advance.
also if you have any questions feel free to ask.
So a history about it. From what I know that is. This was bought brand new by my grandfather we worked for IBM in sales im guessing. (He knows the basics of an engine) it was his daily driver for almost 10 years till he basically totaled it. For 2 years it sat getting a rebuild and when it was finished it came out with basically everything up front, before the dash brand new. Engine,radiator,bumper,quarter panels,etc. Now the engine I believe is another 302 pulled from another mustang and rebuilt. no one knows except my grandfathers mechanic which happened to take it to his grave a few years back. My father (knows a fair amount about cars) then started driving it and kept it garaged. One day we where moving into a new house so he had to move it. I was a toddler so I wasn't all there to see what happened but apparently he was just backing it into the driveway when it suddenly died on him he was unable to start it back up so he pushed it into the garage and never touched it again. Until I had the idea to get her working again.
Any input would be amazing Thanks in Advance.
also if you have any questions feel free to ask.
05-22-2017, 10:27 PM
#2
6th Gear Member
Join Date: Aug 2007
Location: Elk Grove, CA
Posts: 5,896
Test 1) Are you getting 12V at the coil (+) terminal? If so, power is at least getting to the coil. If not, troubleshoot.
Test 2) If you hook a test light up between the coil (-) terminal and ground, does it flash when you crank the engine? If so, the ignition (points or module) is properly grounding the coil to produce spark. If not, something is up with your ignition. If it's points, replace and gap, or replace with a pertronix unit. If it's electronic already, check for proper gap and consider swapping for a known working unit (or points) to verify the problem.
If both of these tests check out, continue.
Test 3) If you hook a wire and plug (and ground the plug, obviously) directly to the coil and crank, do you get spark? If so, the problem is somewhere in your distributor. If not, could be you need a coil. You can verify by testing the resistance between coil terminals.
Test 2) If you hook a test light up between the coil (-) terminal and ground, does it flash when you crank the engine? If so, the ignition (points or module) is properly grounding the coil to produce spark. If not, something is up with your ignition. If it's points, replace and gap, or replace with a pertronix unit. If it's electronic already, check for proper gap and consider swapping for a known working unit (or points) to verify the problem.
If both of these tests check out, continue.
Test 3) If you hook a wire and plug (and ground the plug, obviously) directly to the coil and crank, do you get spark? If so, the problem is somewhere in your distributor. If not, could be you need a coil. You can verify by testing the resistance between coil terminals.
05-27-2017, 04:18 PM
#5
Thread Starter
Join Date: May 2017
Location: Washington
Posts: 4
Test 1) Are you getting 12V at the coil (+) terminal? If so, power is at least getting to the coil. If not, troubleshoot.
Test 2) If you hook a test light up between the coil (-) terminal and ground, does it flash when you crank the engine? If so, the ignition (points or module) is properly grounding the coil to produce spark. If not, something is up with your ignition. If it's points, replace and gap, or replace with a pertronix unit. If it's electronic already, check for proper gap and consider swapping for a known working unit (or points) to verify the problem.
If both of these tests check out, continue.
Test 3) If you hook a wire and plug (and ground the plug, obviously) directly to the coil and crank, do you get spark? If so, the problem is somewhere in your distributor. If not, could be you need a coil. You can verify by testing the resistance between coil terminals.
Test 2) If you hook a test light up between the coil (-) terminal and ground, does it flash when you crank the engine? If so, the ignition (points or module) is properly grounding the coil to produce spark. If not, something is up with your ignition. If it's points, replace and gap, or replace with a pertronix unit. If it's electronic already, check for proper gap and consider swapping for a known working unit (or points) to verify the problem.
If both of these tests check out, continue.
Test 3) If you hook a wire and plug (and ground the plug, obviously) directly to the coil and crank, do you get spark? If so, the problem is somewhere in your distributor. If not, could be you need a coil. You can verify by testing the resistance between coil terminals.
1) I'm getting 12v at the coil.
2) I hook the light from the coil - to the ground it lights up then flickers when I crank.
3)a wire and plug directly from the coil to the ground I get no spark
Not sure what the problem is. Maybe my new coil is bad? Would it be points? Would the neutral safety switch really be my problem?
05-27-2017, 04:26 PM
#6
6th Gear Member
Join Date: Aug 2007
Location: Elk Grove, CA
Posts: 5,896
Could be a bad coil. If you're getting a flickering test light between the terminals, your ignition is at least doing something.
Check resistance between the coil (+) and (-) terminals, and then between the (+) terminal and the spark tower. You should have continuity for each test, although the resistance for the second test should be in the thousands of ohms. If it's open or very low, you need a new coil.
Check resistance between the coil (+) and (-) terminals, and then between the (+) terminal and the spark tower. You should have continuity for each test, although the resistance for the second test should be in the thousands of ohms. If it's open or very low, you need a new coil.
05-27-2017, 06:16 PM
#7
Thread Starter
Join Date: May 2017
Location: Washington
Posts: 4
Could be a bad coil. If you're getting a flickering test light between the terminals, your ignition is at least doing something.
Check resistance between the coil (+) and (-) terminals, and then between the (+) terminal and the spark tower. You should have continuity for each test, although the resistance for the second test should be in the thousands of ohms. If it's open or very low, you need a new coil.
Check resistance between the coil (+) and (-) terminals, and then between the (+) terminal and the spark tower. You should have continuity for each test, although the resistance for the second test should be in the thousands of ohms. If it's open or very low, you need a new coil.
What do do you mean spark tower?
05-28-2017, 08:20 PM
#9
Thread Starter
Join Date: May 2017
Location: Washington
Posts: 4
i checked the resistance from the + on the coil to the socket on the coil and I get nothing. I get power to the coil but as far as I know I'm not getting anything out of the coil when I crank. I'm not sure what's going on I'm stumped.
05-28-2017, 10:10 PM
#10
6th Gear Member
Join Date: Aug 2007
Location: Elk Grove, CA
Posts: 5,896
What's your multimeter range set to? If it's a manual ranging multimeter, you need to set it to ~20k Ohms. Resistance between the tower and the (+) terminal should be 4-20k Ohms, depending on the coil. You may have to clean the terminals up with a wire brush and hold the test leads against them with some force to get a reading.
Adjusting the points (or replacing with electronic ignition) would be a good idea, but I suspect your problem lies elsewhere.
When testing for spark, how are you grounding the plug? You need to make sure you hold it right up against some bare metal on the block/chassis (although away from the battery). If you're brave, you could grab the wire lead in your hand and rest that same hand on the chassis. It won't kill you, but it'll let you know if there's voltage
As an afterthought, how's your engine ground? Should be a ground strap running from the rear of the engine or bell housing to the firewall.
Adjusting the points (or replacing with electronic ignition) would be a good idea, but I suspect your problem lies elsewhere.
When testing for spark, how are you grounding the plug? You need to make sure you hold it right up against some bare metal on the block/chassis (although away from the battery). If you're brave, you could grab the wire lead in your hand and rest that same hand on the chassis. It won't kill you, but it'll let you know if there's voltage
As an afterthought, how's your engine ground? Should be a ground strap running from the rear of the engine or bell housing to the firewall.