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Loud ping at random???

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73blazer73

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so I bought a 73 blazer from a crackhead and I'm decent at turning a wrench with a little mechanical aptitude and automotive knowledge but this metallic Ping is driving me nuts. i start the engine and ping! 30 seconds later ping! 5 seconds later ping! 13 seconds later ping! Driver side exhaust I narrowed it down to. Removed the muffler and catalytic converter from the header. Fired it up and BAM!! Real loud out of the header. Do I have an exhaust valve that's sticking open intermittently? Any ideas would be appreciated.
 
It could be a exhaust valve sticking ,or one thats got a burned spot,that lines up with a bad spot on the valve seat as it rotates and aligns only every so often..the noise a exhaust valve would make if it sticks or was burnt would be more of a intermittent pop or backfire (think jiffy pop popcorn sound),rather than a "ping"...ping is spark knock,and you usually wont hear that unless the engine is under a good load,with too much spark advance..

If it is a ping ,on a later fuel injected engine the knock sensor or distributor can go screwy and cause a ping at any time..

A mettalic ping can be caused by loose torque converter bolts also,or a cracked flex plate...could be a fan blade touching a shroud...two plug wires crossed up and plugged onto the wrong plugs..a lot of various reasons could cause it..
 
Thanks a lot. Good starting points for sure. I already checked the wires as that's the easiest and if I am correct with a firing order of 1-8-4-3-6-5-7-2 there were a few wires that were wrong. Once I hook up the header to the muffler I'll fire it up and see.
 
Well fired it up and it sounds so good! I wish I could post a video it sounds so good. Lesson learned, don't trust that the plug wires are on right just cause they are on there. Bought new plugs. New wires. Oil change. Transmission fluid. Rewired all the electrical. New fuel filter. New alternator. New fuel pump and fuel line. New lock cylinder. New ignition wiring. And I didn't even check to make sure the plug wires were hooked up right. Thanks for pointing out the obvious. Sometimes I over think things lol.
 
Glad it was an easy fix...:)

My friend finds a lot of vehicles at his shop with plug wires on the wrong cylinders often,after someone did a "tune up" and brought in the vehicle skipping and backfiring,running worse than before..

I recall my older brother buying a '56 VW Bug decades ago in the 70's ,for 35 bucks,from a guy who said his son "gave up on it" after he was told it needed a valve job...(he joined the army, and told his dad to sell it if it was in his way)...car was in nice shape otherwise too!..

He drove it home,running on 2 cylinders,skipping and back firing all the way,and it barely propelled the car...to start it he had to jump it with a 12V battery and crank it over a good 15 seconds before it would run on its own..(or push it)..despite the 6V battery being good..

My brother tried a complete tune up--plugs,points,condensor,plug wires,and he put in a carb kit,and adjusted all the valves,did a compression test,it had great compression...and it ran exactly the same..:(

Then he realized he had not checked the firing order,he just put the wires on one at a time,assumed whoever did it last time had the firing order right..--he called a VW dealer and asked what the firing order was,the guy at the service dpartment said "I dont remember off the top of my head--but I think it is stamped on the flange near the generator"..

Sure enough it was, "1-4-3-2" and when he traced the plug wires,he found they had it wired "1-2-3-4" !...after swapping the wires around on the distributor cap,it fired up instantly with no jumping the battery,and it would do a hole shot in first gear and squeak the tires in second...that car ran nice for quite a while too!...(and would be worth several thousand bucks today )..

If your truck was run that way for long,dont be surprised if a muffler decides to start rattling inside,often the backfiring loosens up the baffles in them...it can clog up a catalitic converter too..
 
Thank you so much for all your input. That's two threads now that you've helped me out on. And I've only posted two lol. I have one soon to come about wiring if you're interested haha. Thanks again.
 

Got it running

It is a project in the making

Here's a clip of it running. I had to upgrade to premium membership. This site is just too good.
 
:waytogo:...it does run smooth huh ?...helps when the plug wires are on the right plugs...:rolleyes:..

Now you need to drive by the crackheads house and do a :burnout:..

Thats what I did when I bought a truck (71 K5 CST) from a guy who insisted the engine "jumped time",and acted like he was a "expert mechanic",I couldn't tell him anything...he was good at wrenching but not at diagnosing things,and hated taking any advice from anyone else...
He got so mad at the truck he sold it to me for 500 bucks when I made an offer--just wanted it gone!..
All that I found wrong with it was the distributor cap was in 2 pieces,held on by the screws.(I assume it broke after he went off roading and had the truck off the ground a few times )...and also a lot of hokey wiring with wire nuts everywhere....he also had an HEI distributor hooked up to the original wire for the old point style coil,which doesn't have the full 12V an HEI needs..fixed that right away and it ran even better..

About an hour after I bought it I drove by his house ,stopped,and punched it,left a good 30 foot hole shot..he was outside washing his car,and I heard his jaw hit the ground..:D...he was pretty pissed at me..:whistle:...

I've had quite a few GM trucks and have come to know the wiring harness pretty well--had my share of issues with old corroded or burnt up wires...lets hear what your wiring woes are,maybe I can help..
 
Wow that sounds awesome. I hope with time I can get as good as you at knowing these beautiful machines. I love working with my hands and learning new things so it's always fun. Should I post the wiring as a new thread so others might gain from the info? Will you be able to see it?
 
Yes,another thread for the wiring would be best,then if anyone else is having wiring troubles later on, might come across the post in a search,and gain some advice about what caused it...

By the way,I am no expert mechanic,I have just owned and worked on a lot of the older GMs and you end up getting to know your way around them pretty good...but I still run into things that baffle me or are too complicated to fix myself--one being automatic transmissions..
Filter ,fluid,and modulator replacement is about all I have done to one,I doubt I could put one together correctly if I tried to rebuild one..
I've had quite a few wire fires and corroded wires to give grief over the years and trying to repair them myself is how I ended up knowing where most of the wires go,and what they do..
 
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