65 Runs but missing, even timing light misses.

I just took delivery of a White 65 Mustang coupe--Red interior, 200 CI with automatic trans. Everything is stock (not hot rodded). It starts every time (after a few tries) and runs well enough to drive but it misses consistently--even the timing gun light misses. It has all the typical ignition stuff replaced: plugs, points, plug wires, distro cap, rotor. Even a new Autolite 1100 carb. It had a version with an auto choke but I've swapped it for a manual (personal preference). I was kind of hoping the issue was the carb/auto choke but no change in missing issue. I've checked the mechanical timing--it's a solid 10 BTDC. Mixture is checked. Manifold vacuum 'sucks' (have not checked how much) but distro moves when I suck on the rubber tube. And, yes, it is a vacuum-rated rubber tube. Here's a picture of the Autolite.

https://drive.google.com/file/d/1rOzHyO6rvNX7uox_RriIT4Mp36zLIKut/view?usp=sharing

The Distro vacuum-line comes from the carb (as shown), another V-line runs from the manifold to auto trans (I've read but I've not traced the hard-line back). A third v-line used to run from the manifold to the auto-choke so (for now) it's just plugged. Perhaps this is in error? But playing with the vacuum lines doesn't seem to affect the issue one way or the other.

The issue is that the pony--while it 'runs', is not really drivable--due to the missing--especially on acceleration. When I get a head-of-steam up, it runs but it's rough. It never stalls (as long as the idle is high enough). But when I put the trans in R or D it clunks--O or L is fine. If that's a bad sign, let me know.

>> Seems like the timing light missing (not strobing) in sync with the actual engine missing should be a clue. But pretty much all the ignition stuff is new.

Any 'informed' hunches would be appreciated.
Thanks!
 
Swap plug and wires around and see if miss follows. I've had a new plug not fire on two occasions. Bad out of the box.
 
> recently had similar symptoms with a 63', after much foolin' - found the brand-new (offshore source) Condenser would crap out with a weak spark after initially providing fire.

(bad out of box too)

KISS' - maybe give another condenser replacement a try b4 getting any deeper ...
 
Also consider the ignition coil. The issue is spark, not the carb so if the points are gapped right and the plug wires are good, the coil OR voltage to the coil is suspect. If the condenser was changed with the points, put the old condenser back in it if you have it.
 
If you have not done a compression test yet, you should. You mentioned a vacuum test, was the needle fluctuating with the miss?

Lou Manglass
 
Vacuum leak? Looks like a pencil stuck in your C4 vacuum line at the intaKe manifold. And then there's some sort of line connected to a throttle linkage attachment point on the carb spacer - this is normally just for a bolt, not a vacuum line.
 
Back
Top