What am I missing?

[john2189]

1967 mustang 289 Was running very rough. I replaced points, cond, rotor, and cap. Started it up, ran a bit better. Was warming it up to adjust carb, after 10-15 minutes, it just stopped running. Would not start again, fired some,but then it stopped that. I checked spark, very weak at coil wire. Ran battery down, so put on charger next day I used sandpaper on points and cleaned with paper. Better spark but no spark at spark plug wire. Put old cap and rotor, still no spark. Tried a different coil, no luck.

What am I missing? I’ve worked on engines for ever.
John

[Jim Becker]

Try a condenser, maybe the one you took out.

[john2189]

Try a condenser, maybe the one you took out.

Planning on doing that tomorrow

[Gary Dotson]

Also, re-check your point gap, it might have slipped, closing the gap. Better yet, check and set it with a dwell meter.

[john2189]

Also, re-check your point gap, it might have slipped, closing the gap. Better yet, check and set it with a dwell meter.

Points is set to .017. I don’t have a dwell meter

[Gary Dotson]

A long shot but I've seen it before! Make certain your dist. housing is well grounded. A point ignition will not function if the breaker plate is not well grounded. Some have a braided ground strap between the plate and the housing, I don't know if that one does or not. I've also seen situations where the dist. housing does not make good ground contact to the engine block. These thing can be confirmed with an ohm meter or simply trial and error testing with an alligator test lead.

[john2189]

A long shot but I've seen it before! Make certain your dist. housing is well grounded. A point ignition will not function if the breaker plate is not well grounded. Some have a braided ground strap between the plate and the housing, I don't know if that one does or not. I've also seen situations where the dist. housing does not make good ground contact to the engine block. These thing can be confirmed with an ohm meter or simply trial and error testing with an alligator test lead.

The distributor does have the braided strap from the dist housing And the points hold down screw and I did hook it back up. I did loosen the dist to move the timing a bit. I do have spark at the dist wire, but it’s not going through the rotor and cap to the plugs. I’m going to put the old condenser back in to see if that makes a difference

[john2189]

Ok I put the old condenser in, it started right up.

[ricky racer]

Ok I put the old condenser in, it started right up.

Thanks for posting this John. By closing this loop we all get a chance to learn something.

[Gary Dotson]

Years ago, even when we still had quality tune up parts available, it was often said that if you had a properly working condenser, you might want to leave it alone. Even then, we ran across a bad one, that would make life miserable for an hour or two, every once in a while. We always wondered why they were, routinely, replaced on a tune up. We replaced them, because customers expected it, but it made no sense.

[john2189]

Back to the mustang. It has two cylinders not fireing. # 1 and 6. New wires didn’t help. I put a known good plug in no different. Compression was 90#.

what next? Remove valve covers to make sure valves are working?

[Urbish]

Even at that low of compression it should still fire at high RPM. You sure your got the firing order right? Pull the wires for #1 and #6 and verify spark externally with a known good plug grounded to the engine.

[john2189]

Yes everything checked good. I’ll pull valve cover and adjust valves next