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302 not firing on cylinders 2 and 3

Posted: Sat Apr 20, 2019 9:24 am
by Olilux
Hi am puzzled...
I have a 1974 with 302 and Automatic.

My engine runs fine and smooth but is not firing on cyl 2 and 3 but check this:
1. Compression is over 120PSI on all cylinders.
2. Firing order checked a million times, time checked with marks all ok
3. All valves are opening (I opened the valve cover and just fine)
4. Replaced spark plugs, wires, distributor & rotor... no change
5. removed carburator (2100) replaced all caskets and heat shield (no change...)

It looks as if these cylinders are dry. I have nothing left than to remove the intake manifold and see if there could be an object blocking but blocking both??

Anyone with a clue?

Re: 302 not firing on cylinders 2 and 3

Posted: Sat Apr 20, 2019 4:24 pm
by Stan
How did you determine that #2 and #3 aren't firing?

Re: 302 not firing on cylinders 2 and 3

Posted: Sun Apr 21, 2019 2:32 am
by Olilux
When engine is running, I unplug one one cylinder at the time on the distributor and normally you hear a change in tune. On 2 and 3 no difference when I unplug the wires.

Re: 302 not firing on cylinders 2 and 3

Posted: Sun Apr 21, 2019 8:40 pm
by Stan
I've had varying results with pulling spark plug wires one at a time. I find it better to connect a timing light to each plug wire and then see if it " lights up " . That will tell you if you're getting spark to that wire .
One thing to check is the spark plug wire where it connects to the spark plug connector . I've seen the "conductive" part of the wire disconnected from the plug connector so there is spark to the wire but no spark to the plug.

Re: 302 not firing on cylinders 2 and 3

Posted: Thu Apr 25, 2019 12:22 pm
by Olilux
Stan thanks for the feedback.
I never found out what it was really. I exchanged threads, spark plugs, distributor and rotor. Now all is working fine. Runs like a star.