Please help with engine trouble

[darush01]

My 72 c20 is my dd and the other day I burned up a plug wire on the exhaust and once I replaced it it ran a little better but still bad, I did some checking replaced another plug wire bc when I pulled the wire from the cap with the engine running nothing happened then I replaced the plug because it had some white substance built up and couldn't have been firing, but it still didn't fix the problem I plan on replacing the whole set of plugs and wires ASAP but I don't think that's the whole issue, it's got a newer set of points and a newer cap and rotor, I'm lost I think at least that cylinder is not doing anything and it was kinda sudden I mean one minute it's fine the next it's not please any ideas?

[litew8]

got pics?

does it resemble any of these? link

[frank69]

pull all the plugs and check compression.

[WorkinLonghorn]

You need to perform a compression check. Go ahead and do all cylinders and write down the results. Follow the instructions that come with the gauge, don't forget to have the throttle open full and all pugs removed.
That would be my first step.

[darush01]

I'm trying to upload pics hope it works

[darush01]

Here's the one plug I did swap

[darush01]

Other side

[darush01]

Ill do that when I go to change the plugs I just need to get a gauge

[FloatMonkey]

I would also check the vacuum too. I am guessing a broken valve spring.

[darush01]

But what's up with the stuff on the plug what caused that

[darush01]

I was afraid I might have to pull the head I'm gonna try to test compression and vacuum and see what I can get from there

[FloatMonkey]

The white stuff on the plug is ash buildup. Pretty common on older engines.

[litew8]

Not sure how common that might be. How old are they? When you replace plugs and wires, you should switch them all out together.

[darush01]

I normally do change them all at once but it seems like I haven't had the money recently so I tried just the two wires and one plug I feel kinda embarassed to admit it but it kinda slipped my mind and I forgot to do a tuneup the plugs are about 3 years old and I have no clue about the wires they were on it when I bought it over 4 years ago all I know for sure is I've changed alot of stuff just kept forgetting those two things it has a new cap and rotor about 3 months old and points at the same time oil is due but just barely carb is new to me and ran fine when I pulled it off the other truck the fuel filter is new I think that is everything that I've done recently that would affect how it runs

[litew8]

How bad is it running, and it happened overnight? Does it sound like one cylinder isn't firing, really rough idle and acceleration? The white might mean it's running too rich. Make note of what the other look like when you get to changing them. p.s. I don't recommend pulling on wires while the engine is running.

[darush01]

You described it right it idles rough and accelerates really rough when I get it wound out it evens out, but I really wasn't afraid of the shock it got me by suprise on that burnt wire but I've been shocked before and will be again I'd rather it be 12v than 110, but I was just trying to narrow it down to one cylinder and there are a few that seem stronger than others but thts the only one doing nothing at all

[slow-1]

All new plugs and wires, check the points (file the new ones you put in recently if needed), check the cap and rotor (may have fouled the contacts with the burned wires) it will run like new...unless, of course, something else has gone wrong.

[cdowns]

i'd start by setting the points to the proper dwell

[NoNeck]

That one plug with the white ash coating looks like the plug in the photo below showing "DEPOSITS".

Maybe you can read the reasons in the photo.

X2 on changing all the spark plugs and wires. Make sure you use the correct spark plug and quality wires.

Good luck,
POP

[NoNeck]

Oops... here is the photo.

POP

[litew8]

You haven't mentioned, but check and ensure there is spark for that wire.

[darush01]

I was getting spark to that wire and haven't changed them yet due to money problems but I did get stuck in the dq drive through I just lost all electrical power so I pulled everything on the battery apart cleaned the posts and cable ends and even the cables checked both ends of both cables and it ran a little better after I got it to start back up I mean it still had the sputter but not as bad, I'm working 12 hour shifts until next weekend but then I'm hoping I can change the plugs and wires and if that don't do it I might even do the points cap and rotor again just to be positive

[southern parts]

make sure your new plugs are gapped right too. with points type distributor they should be .035 thousandths

[darush01]

Yes, I have it written down so I don't forget where to set them

[darush01]

I was gonna run delco plugs any preferences with wires? I want good but I've always just ran the cheapest so I don't know what wires will work best and not be too expensive