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strange ticking noise what'd i break?

iamdave0887

iamdave0887

Here Comes Chaos.....
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hey guys.

I hope this thread doesn't turn out as grim as i'm feeling right now. This thread will decide the blazer's fate i think.

Long story short i was coming up a big hill and was into the pedal a tad. All gauges were normal. Engine was at operating temp below the 200* mark on the temp gauge. Oil was just over 40 psi. Just over 1/2 throttle or so when i heard this awful noise. It sounded like a knock so i pull over but can't get out and check on the busy road. Flip my hazard lights on and see if the truck will move. It drives like it always has, trans shifts fine, clutch engages and disengages fine with no slip when i stomped the go pedal a few times. It has the same power it's always had. No more visible smoke than normal(a small puff when i take off in 1st gear and if i shift too soon i get a little smoke in 2nd gear until the engine isn't lugging anymore)

So i pull into the driveway thinking all these terrible thoughts about my engine's health. I roll over the block that's my "emergency brake" make sure the truck is in neutral, let off the brake and the truck doesn't roll, pop the hood and get out. Then the damn truck starts rolling backwards on me and fast. It slammed right into the old portable basketball hoop at the bottom of the driveway. Scared the life out of me watching my truck roll away. No visible body damage to the truck so it must've hit the bumper trim. So now i'm just pissed off. I get in the truck shove it in 1st gear and pop the clutch spinning both tires in the process of going back up my driveway.

Anyways, I checked the balancer , not loose at all and all rubber seems to be intact. Same goes for the crank pulley, it''s fine. It's got a metal to metal sounding tap that i can't place very well other than it sounds like it's coming from the passenger side somewheres. I pulled off the oil cap, almost no blowby(same as always). Pulled the oil dipstick expecting to find metal, yet i didn't find anything. The oil's black as sin but no surprise there(only 1,000 miles on the oil). The tap follows engine RPM. At it's lowest point oil pressure was just over 20 at idle and when i brought the RPM up just a touch it came up to 40 lbs and went past 40 when i revved it higher.

Could it be a stuck injector? The injectors are kenny's old Tahoe injecotrs that he said had about 160K on them IIRC. I had enough energy to crack one injector line(driver's side front most), giving myself a knuckle buster in the process and the truck started to miss but the sound was still present. Tighten the line back up and the miss was gone.

If i busted the crank it would make a hell of a racket wouldn't it? If the crank was busted i wouldn't expect it to run as smooth as it always has. If i spun a rod bearing wouldn't oil pressure be low and i'd have metal in the oil correct?

Could i have a lifter plugged with crud considering how long this truck sat for.

Any idea what i could've busted?

I don't know folks, my heart just feel torn out right now. I put so much into this truck, i'd hate to see it go like this.....:sad:

- Dave
 
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Injector is possible and probably the easiest to check for. You should take a video and post it up. Might help us help you out.
 
use a stethoscope to pinpoint the noise. If you don't have one a long screwdriver or extension can work although every mechanic should own a steh. Bad injector will be more of a pinging metallic sound. what you are describing could be a rod knock or a dropped lifter Really kind of hard to dianose from a keyboard. You have to poke around and find where it's coming from. I doubt it's the crank, you wouldn't be driving it. Worst case scenario drop the oil pan. It's a 15 min job on these style trucks and take a 12 in ext with what every size socket the rod bolts are and stick it on each rod one at a time and use it as leverage to see if there is slop. If all rods feel tight then pull the main caps one by one. Try to find it with the steh first before doing all that. even if the motors toast, it's a 6.2. You could by a used one from 3-600$ . A bad injector would probably smoke as well. The injectors are easy to get at and should be reasonbale easy to looosen given that you changed them not too long ago. Loosen them one at a time and see if any change the noise. That could narrow you to which cyl.
 
ak diesel driver said:
Did the older 6.2s like that have the plastic in the rockers?
Click to expand...

The motor's not as old as the truck. It's a goodwrench crate, which when it was installed was brand new.

I"d think it would have the plastic rocker retainers. If a retainer let go would that cylinder stop firing or fire erratically? It's running smooth save for the noise.

I did have a tick like this once or twice before that sounded the same, but it always went away on its own. i figured the tick was from the oil being hot and thinning out a tad bit. Guess not....
 
Acesneights1 said:
use a stethoscope to pinpoint the noise. If you don't have one a long screwdriver or extension can work although every mechanic should own a steh. Bad injector will be more of a pinging metallic sound. what you are describing could be a rod knock or a dropped lifter Really kind of hard to dianose from a keyboard. You have to poke around and find where it's coming from. I doubt it's the crank, you wouldn't be driving it. Worst case scenario drop the oil pan. It's a 15 min job on these style trucks and take a 12 in ext with what every size socket the rod bolts are and stick it on each rod one at a time and use it as leverage to see if there is slop. If all rods feel tight then pull the main caps one by one. Try to find it with the steh first before doing all that. even if the motors toast, it's a 6.2. You could by a used one from 3-600$ . A bad injector would probably smoke as well. The injectors are easy to get at and should be reasonbale easy to looosen given that you changed them not too long ago. Loosen them one at a time and see if any change the noise. That could narrow you to which cyl.
Click to expand...


It is a metallic pinging sound.

Here's a vid i found on youtube. it sounds like this, but it's not as loud sounding.

http://www.youtube.com/watch?v=orbbourGCOQ

It's dark out right now so i can't see if there's any smoke, but come to think of it on the way home it was smoking a bit more than normal. normally i get a slight smoke when i take off in 1st(just a puff usually) and if i lug 2nd with the RPM too low(shifting too early) i'll get some smoke.
 
The only thing these guys missed is line knock, Dave, but I have another thing to comment on, if ya don't mind...

Years ago, I parked my little Toyota 4x4 in my Dad's driveway, put my hunk of birch behind the front wheel and went in the house. The next morning, I went outside in the dark, swept off the snow and started the truck - put it in neutral to let it warm up and went inside.

When I came out, the truck was down the street, through the neighbor's fence, on his front lawn. Sounding familiar, yet?

I talked to the neighbor, made arrangements to come fix his fence, got in and drove home. Then I got out and kicked the truck.

Dad (being the wise-ass I learned from) said "Yep... sure taught it a lesson"

Fix your E-brake, young fella. :D

Jim

PS - hope you find the knock... sounds injector- or line-related to me.
 
well on my crappy little speakers had to be sure but that sounds like a bad cam or lifter. Not to mention his truck starts like shit and needs batteries....:D
 
iamdave0887 said:
The motor's not as old as the truck. It's a goodwrench crate, which when it was installed was brand new.

I"d think it would have the plastic rocker retainers. If a retainer let go would that cylinder stop firing or fire erratically? It's running smooth save for the noise.

I did have a tick like this once or twice before that sounded the same, but it always went away on its own. i figured the tick was from the oil being hot and thinning out a tad bit. Guess not....
Click to expand...

Plastic rocker retainers is the first thing that came to my mind as well but i would also assume that it would cause irratic missing.
 
I got a set of Bosch Nozzles that I bougth by accident thinking they were the whole deal. They are new I beleive. I paid 60$ for them. IDK though...Well easy enough to figure out. Loosen the injs one by one. If the noise goes away you have your culprit..
 
Hahaha I don't think I ever owned a truck with a working e brake when I was Dave's age....Of course time and age comes wisdom. In the old days...Lift'er up and torch the cables...:D
 
Alright your still on line cause I see your watching...Git your arse out to the garage with your 3/4 crow's foot flare and loosen some lines.... Report back. it's a 6.2 not a 6.5. Piece of cake to do.
 
Acesneights1 said:
Alright your still on line cause I see your watching...Git your arse out to the garage with your 3/4 crow's foot flare and loosen some lines.... Report back. it's a 6.2 not a 6.5. Piece of cake to do.
Click to expand...

I think i'll sleep on it(i'm beat anyways) and check the injectors in the morning. i did crack the driver's side front most one and the truck started missing on that cylinder but the tick was still present.

If it's not an injector what else could it be?

The harmonic balancer looks fine with no cracks in the rubber nor can i move it at all, and trust me i tried. Ditto for the crank pulley. it's solid as well.

If i trashed something major internally i just can't see it running as well as it is. I did go out and attempt to get a video but the camera is demanding more AA batteries and i'm out of them. I did start it up and the oil pressure was just under 60 psi at idle. Would it hold that kind of pressure with something majorly wrong in the bottom end? Something tells me no, but i'm not 100% sue.
 
stop guessing. One injector is not enough. Do them all. even if it's a rod knock taking the fuel away should give some change. If it's a Nozzle it should go away. You can also pull all the belts if you think it's an accessory. Again hard to hear from a you tube vid. I would grab a stehoscpe and try to pinpoint if lossening the injectors does no good. These are very very simple engines. Not a whole lot can go wrong with them.
 
randomid25 said:
A bad lifter is the only other thing i could think of. Don't know how to diagnose that.
Click to expand...

Unfortunaly on one of these it's very difficult because to remove the valve cover you have to pull the inj line then you would have to re install them to run it unless you can physically see a rocker flopping in the breeze. I usually get it running again and go alng with the wood handle side of a hammer against each rocker while it's running to see if the noise goes away. It's unusal AFAIK for cams to go in these motors though. I have owned 4 6.2s with well over 300K and original cams. Course anything is possible. I lost a 6.2 to a broken friggin air cleaner sud.
 
Acesneights1 said:
stop guessing. One injector is not enough. Do them all. even if it's a rod knock taking the fuel away should give some change. If it's a Nozzle it should go away. You can also pull all the belts if you think it's an accessory. Again hard to hear from a you tube vid. I would grab a stehoscpe and try to pinpoint if lossening the injectors does no good. These are very very simple engines. Not a whole lot can go wrong with them.
Click to expand...

The thing that bugs me is it was loud at first(if it was even the same sound i don't know). when i heard the first sound i figured i threw a rod. it was a loud metallic like noise, and then it went away just as quick as it showed up. The loud sound almost sounded like a stone getting kicked around in the bellhousing. No inspection plate(gasser one doesn't fit) and the offroading over the weekend could've caused that i'd suppose.

I drove a bit more(a few miles) and just as i was getting home i heard the ticking at the stop sign before my street. No idea how long it was ticking for really. The first sound seemed to come from "under" the truck(and it went away with a "tink! noise like a stone getting thrown out of the bellhousing almost), where as this ticking seems to come from the engine bay. I think it was two different sounds now that i think about it.
 
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