[aggiecoug]

I have a 289 with cylinders 3, 7, and 8 not firing. Does anyone know what it could be? I've been messing around with it and this is what I've found...

-Compression ranges between 120 and 150 in all cylinders.
-I've watched the rockers go up and down, and they all seem to be moving.
-I just pulled the heads for a valve job, but the engine feels the same as it did before, so I don't think it's the valve adjustment as I had to adjust the valves when I put the heads back on.
-The wires are fine. I've switched them all around to different cylinders, but the same cylinders aren't firing.
-The wires are in the right positions, I've double and triple checked them.
-The spark plugs are about two years old and have very few miles on them. All but one look good, and the one that doesn't look so good is only slightly discolored.
-I've replaced the distributor cap and rotor, and no change in performance.

Any help would be greatly appreciated.

 

[lbesq]

Have you checked for spark through the wire at the plug? Perhaps your cap is cracked? Just my 1/5 of a dime
Lloyd

 

[Old man]

I've found wires not properly plugged into the distributer cap, so that while the wire itself checked out, there was high resistance between the contact inside the cap & the wire itself. another 2 cents. Paul

 

[doctordesoto]

10 to 1 its a vacuum leak---try plugging all the vac lines and see how she runs---we fought a 69 forever and it was a bad ligth switch leaking vacuum
doctordesoto

 

[aggiecoug]

Thanks all, I'll check out all of your suggestions tonight.

 

[aggiecoug]

Well I found some time in the day to buy a can of carb cleaner to look for vacuum leaks, and the problem may be solved! There's a leak at the base of the carb near the back. I'll have to go get a gasket and keep my fingers crossed

 

[aggiecoug]

Back on all 8! I found four vaccuum leaks and sealed them all. Runs nice and smooth now, and plenty of power. Thanks all!

 

[fastmerc]

AHAH!!! The dreaded 4 vacuum leak problem...... Was this from the universal 4V gasket with the extra mounting holes that leak into the 1" carb spacer vacuum cavity???

If so, very common mistake.....I did it too a looooong time ago!

Steve

 

[aggiecoug]

No, they were all sepearate, but I'll certainly remember that if I switch to a 4V!