Two Plug Wires Off and Still Running?

shwingdom · Member

Two Plug Wires Off and Still Running?

58 poncho fan · Addicted!

I would check vacuum with a vacuum meter. You could have a bad vacuum leak somewere! Spray oil around the intake manifold and if blue smoke comes out the tailpipe you will need to replace the manifold gaskets!

beaumontwagon · Guru

So if you have all the wires on and start pulling 1,2,3,or 4 the motor reacts right away?If so you might have a worn out cam or a problem with the valvetrain.

2drpost · Uber Guru

first check the wires aren't crossed,
then do a compression test.

if those 2 cylinders aren't firing, you'll get a rich exhaust smell.

shwingdom · Member

I tried spraying WD40 all around the intake and no luck.
I replaced all my vacuum lines as well.
And to reply to the wire pulling, 1,2,3,4 have effect 5 and 6 do not.
Thanks so far, it doesn't look like an easy fix now.

Jim

shwingdom · Member

If you mean the 5th wire is in the 6th position and vise-versa, I checked that already.
Compression in the cylinders range from 145-150.

beaumontwagon · Guru

Compression seems ok.With the valve cover off,look closely to see if all the rockers are moving the same amount.I thats ok I would do a tuneup,cap wires rotor,plugs.

beaumontwagon · Guru

Might have spark when cranking,but sporadic while running.Or even a bad plug.

shwingdom · Member

I keep seeing in the original shop manual about the spark plug gaskets.
Of all the Delco ones I have bought, no gasket included.
How crucial are they?

2drpost · Uber Guru

'74 engines had tapered seat plugs, no gaskets.

eeluddy · Uber Guru

With the valve cover off you can see if its a stuck lifter. Tap the 2 in question with a rubber mallet when its running, sometimes that frees them up

ak 67sd · Poncho Master!

Like Dave suggested, check your rockers, you may have two flattened out lobes on your cam...

ak

shwingdom · Member

That sounds reasonable, I'll try that in a few days.
Thanks for all of your help.

Jim

Beaumont4008 · Uber Guru

Also check your EGR valve as you mentioned is a 74 engine. When they start failing they open to soon and let a lot of exhaust gas in to the intake to early and run like crap but will run ok at a higher rpm.

shwingdom · Member

I also heard today that maybe my manifold gasket may have a break internally, and in turn, bridge the 5th and 6th cylinders.
So I ordered a gasket from NAPA and they are telling me that the 250 only takes one, I thought 2 gaskets were needed.
Any ideas?

I'll say it again, you guys are all a great help!

Jim

4SPEED427 · A Poncho Legend!

I forget which years do what but make sure they are looking up the correct year. Not all gaskets are the same on the 250, that much I recall.

gparis7 · Canadian Poncho Superstar!

shwingdom wrote:

If you mean the 5th wire is in the 6th position and vise-versa, I checked that already.
Compression in the cylinders range from 145-150.

Compression is 145-150 on all 6?
I had the same problem once in a 350 Z28; valves were lashed too tight on two cylinders. Readjusted them and solved the problem.