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Discussion Starter #1
well on my way to town today all of the sudden it started running rough especially coming off from a stop and i dont know where to start to fix the problem

if you dont already know from my other posts its a 1985 gmc sierra classic

it was running so good earlier i couldent have been happier with it and now this :00000060: :eck16:

i also hear a tapping sound i think its coming from the valves but im not positive

i tried mashing on it from the stop sign figuring that there might be a piece of gunk or something under a valve but that didnt change anything

can someone help me on this, im getting really sick and tired of this **** truck its not even funny it seems like if its not one thing its another :banghead3
 

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Gearhead
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From your description, the first thing I would look for is a broken valve spring.

I'm assuming this still has the stock cam? They had trouble rounding cam lobes around that time. That would be the second thing I'd look for.
 

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Discussion Starter #3
ok what do you mean by rounding cam lobes?

cause it was running perfect one minute and like crap the next anything else to look for? it wouldent be that it just needs a valve adjustment would it?
 

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Discussion Starter #4
ok i just got her in the garage and the tapping is still there and its coming from the exaust i listened with a screw driver on varoius places underneath, trans, oil pan then the passenger side exaust pipe and i found it now what would cause that?
also, the tapping will fade out for a second or 2 then come back sometimes at an idle, tapping also gets faster if the engine is idled up

im in the middle of running a compression test now, going to finish the last 2 holes will come back with results
 

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Discussion Starter #5
ok done with that, when i pulled the last plug on the passenger side it was wet with gas. so i thought i found which cylinder its coming from, and i did. so i ran the compression test and that one came up to be a little weak. so i cleaned up the plug and put the wire back on and started it i still heard the ticking, then i saw it, that wire was laying on the exhaust manifold! the rubber on the wire was wore down to the middle and causing it to arc to the exaust manifold so until i can get some new wires AGAIN! i put electrical tape on it and took it for a ride.

runs smooth, no ticking, and its somewhat back to normal. now that its 1:30 in the morning here, i can finally sleep knowing that my beloved truck is working properly again.

and here i was ready to pull the valve covers, TONIGHt and look for a busted spring ha ha. but thats why i was doing the comp test in the first place was trying to find the cylinder with the busted valve, thanks Smiley
 

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Premium Member
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When you get a chance a tune up would not hurt. Cap,rotor wires and plugs at least. Have it timed and you'd be surprised what a difference it'll make.

MU
 

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Cool. glad you figured it out. When I started reading thats what I thought it was.

There are planty of diferent styles of ing wire holders out there to hold the wires out of the way. Also I have had good luck using wire ties. Loop a wire tie around two wires loosly. Then take another and wire tie the loose loop part of the first tie between the two wires. Then tighten them bolth up. That will hold the wires together, and still have a space between them to prevent crossfiring.
 

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Discussion Starter #8
yes i got new spark wires this morning and put them on. i used zip ties to hold them up. i was careful to make sure they were well out of the way of any extreme heat

plugs are new also

runs good now
 
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