Ford 3000 ignition issue

[Rsator]

1975 Ford 3000 3-cylinder gas engine. It was running fine but then began first to cut out under a load. Then idled very rough. Difficult to start. Just last year I tuned it with new points, rotor, condenser, cap and coil. That improved its performance. Now, I cannot get spark out of the distributor. I again replaced all the aforementioned components and I have gone through each step to recheck points gap etc but still no spark from the distributor. When I use a circuit test light on the plus (ignition) side of the coil I get a good light when I turn on the ignition switch. When I touch the test light to the negative (distributor) side of the coil, I get solid light that doesn’t change even when cranking the engine - since I wasn’t getting a flashing light I suspected points were staying open but that it is not the case. I get no spark at any plug - before I replaced ignition parts I would intermittently get spark at the plugs but it still ran rough. Any ideas for this man with limited mechanical skill would be greatly appreciated.

 

[Bob NY]

1975 Ford 3000 3-cylinder gas engine. It was running fine but then began first to cut out under a load. Then idled very rough. Difficult to start. Just last year I tuned it with new points, rotor, condenser, cap and coil. That improved its performance. Now, I cannot get spark out of the distributor. I again replaced all the aforementioned components and I have gone through each step to recheck points gap etc but still no spark from the distributor. When I use a circuit test light on the plus (ignition) side of the coil I get a good light when I turn on the ignition switch. When I touch the test light to the negative (distributor) side of the coil, I get solid light that doesn’t change even when cranking the engine - since I wasn’t getting a flashing light I suspected points were staying open but that it is not the case. I get no spark at any plug - before I replaced ignition parts I would intermittently get spark at the plugs but it still ran rough. Any ideas for this man with limited mechanical skill would be greatly appreciated.

Sounds like you have a broken circuit between the coil and distributor.

 

[Rsator]

Sounds like you have a broken circuit between the coil and distributor.

I am thinking along those lines. If correct, I guess I should be looking at the wire that connects the coil and the distributor. I see only the one wire. I will try to disconnect it at each end, then do continuity check on the wire. I will also see if the wire is somehow connecting to a ground point along the way. Thanks.

 

[JMOR]

I am thinking along those lines. If correct, I guess I should be looking at the wire that connects the coil and the distributor. I see only the one wire. I will try to disconnect it at each end, then do continuity check on the wire. I will also see if the wire is somehow connecting to a ground point along the way. Thanks.

Given, "When I touch the test light to the negative (distributor) side of the coil, I get solid light that doesn’t change even when cranking the engine....", that implies an open circuit, not a short to ground. Look for continuity from distr side of coil all the way to points themselves and that the two contacts of the points are making 'electrical' contact, not just that they are touching each other. Virtually invisible oxides often insulate one contact from the other.

 

[Eman85]

As JMOR said the points can be breaking and making contact but not flow current due to corrosion. Key on use your test light to see if the one side of the points has power. You can be your own set of points by putting a spark tester on the coil wire and making and breaking the circuit with a screwdriver or a jumper. When you do this the spark will jump at the tester if the coil is good.

 

[Rsator]

As JMOR said the points can be breaking and making contact but not flow current due to corrosion. Key on use your test light to see if the one side of the points has power. You can be your own set of points by putting a spark tester on the coil wire and making and breaking the circuit with a screwdriver or a jumper. When you do this the spark will jump at the tester if the coil is good.

I will definitely do the connectivity test on the points. Just for information, the points I took out looked very good and it now has new points. Still wondering about the wire from coil to distributor but will test for both. Thanks for all the help and suggestions.