Sorry, I re-posted in this section thinking it was a better place for it, admins if you want can you please delete this thread in the 97-03 section.

This is a truck I just bought, I sold the last lifted 99 5.4L I had.


New truck for me... is a 99 with 120k, 5.4 4x4 auto sc. I got the truck for dirt cheap. Its very clean (will have pics up soon) nice glossy black and matching trim, good tires...4x4 works great, tranny shifts smoothly. BUT..... I noticed today (2 days after buying it) that around 3k it knocks. I can barely hear it (and didn't notice) at low rpm's or idle. But now that I know its there I can faintly hear it at low rpm's and Idle. But at 3k it lets out a pretty loud knocking noise. Now, I know they had issues with the passenger side exhaust manifold which this one also does also but its not that. Seems to be coming from the bottom end, not sure until I can get someone to rev it up for me while I look around. Just curious if there would be a particular bearing that wouldn't make any noise until higher rpms? Like I said now that I know its there I can hear it at low rpms but anyone else wouldn't notice... and it runs strong and fine under 3k then knocks pretty loud. I'll try and get a video of it. I would just like to have some knowledge before I go into a shop blind.
I know you cant diagnose it just by what I've told you but any ideas would help. Thanks

I tried to get some video but the background noise is horrible therefor you cant hear the knock as well. So I'll try it again tomorrow.

 

unplug the fuel injectors one at a time, if its a rod bearing or wrist pin it will get quieter or go away when you unplug that injector. it is also possible that it has just developed a bit of piston slap...which in reality wont really hurt anything as long as its not burning a large amount of oil.

 

Ok, I'll try and get around to that tomorrow... busy with work but will try, sounds simple. Is it going to throw a misfire code when I do that? As far as I know it doesn't burn any oil, The oil that was in it before it got changed today was definitely old and was right at the top mark. It doesn't leak any fluids. My last 99 5.4L burned through 1 quart between changed.. but I kept it topped off, was never any noises though. I'll repost tomorrow with some updates and hopefully a video with some decent audio. Thanks

not sure if this will work, here are the crappy videos i tried to take a few minutes ago. The one looking at the dash bezel for some reason has some background noise. Right at 3k or just a hair after you can hear the knocking if you listen closely.

http://s11.photobucket.com/albums/a1...t=SDC11950.flv

 

yes you will need to clear DTCs after doing this, it will set a missfire DTC and an electrical DTC for each injector you unplug. You can just disconnect the battery for a few minutes if you do not have a scan tool.

 

here is the second video, it is just audio, again... very hard to hear the knock on the video and I'll get some better video tomorrow but it is very noticeable while in or out of the truck, just cant hear it very good on the videos

http://s11.photobucket.com/albums/a1...t=SDC11953.flv

 

No problem, figured. I should probably take it through deq and dmv before I do that since I just got it and need to register it. It should pass. Last time I cleared the codes on a truck, it took a week to complete a drive cycle before I could take it through emissions or it would come up "not ready to test"

 

yes the P1000 DTC takes a while to go away.

 

just another thing that popped into my head..make sure all your plugs are tight, it may be ready to spit one out its pretty common as well.

 

New videos today. Got a chance to talk to a 30yr mechanic family friend today and completely described the sound. He was asking me if the sound is when the idle is being picked up, steady, how it changes in pitch and all sorts of stuff and exactly described to me what he thinks and is 90% sure its a main bearing. Kinda sucks but in some weird way I'm a bit excited about a possible overhaul and upgrades. Money isn't a huge issue.. I didn't want to have to empty my pockets for the issue but somewhat anticipated having to put a few bucks into it. Plus I can get all the work done at no up charge, just parts and minimum labor through him. Have already spoke of a basic build cost and its nothing. Just sucks cause I'll probably be out a truck for a few weeks. Anyways, here's some better sound quality videos, the first longer video you can hear the passenger exhaust leak in some of the revs but listen closely and you'll hear the knock, especially at the end. There's also an intermittent ticking noise. It's going to his shop on saturday to be sure.

http://s11.photobucket.com/albums/a1...t=SDC11958.flv

 

This video is from on top. Had to take the camera out of the engine bay to keep out the background noise.

http://s11.photobucket.com/albums/a1...t=SDC11970.flv

 

and another one....

http://s11.photobucket.com/albums/a1...t=SDC11971.flv

 

Build up that bottom end for sure...then throw some boost at it

 

I've never had a main bearing start knocking at 3K, always made noise at idle and knocking noise would increase with rpm.

I'd remove the belt and run it again just to make sure it's not something else and if the noise is still there I'd remove the cam/valve cover and check inside.

It may be a loose timing chain too ?? Doesn't sound like a 3000 rpm noise but more of a lower rpm knock or slapping noise that's why I'm thinking something in the valve train.

Check the easy stuff first !! Good Luck

 

Well the mechanic sais he thinks theres 2 bad wrist pins and a main bearing. The lower rpm intermitten tapping are what he thinks wrist pins and the deeper louder knock is a main bearing. Might take it in for a seond look just to be sure but either way its no good news and is going to come out. I don't think I have the time to do a build, right now its my daily driver so 2-4 weeks out on a build isn't an option right now, plus my taxes wont be in for a while more. So I'm left with the easier option, low mileage engine. Anyone know a good place to look for a low mileage engine, not remanufactured. I'm trying to find a place that can vin verify mileage, guarentee compression and anything under 50k miles with a 12 month/mile warrenty at a descent price. Also not looking for anything that come from a roll over, front end collision or flood recovery. I found a 5.4L out of a 2000 with 10k miles for $1,200. seems too good to be true.. the business is closed today so i wasnt able to get any details on it. I just don't know of any good reputable engine sales sites. Any help is appreciated. This is for a 99 5.4L 4x4 8th vin L

 

Car parts.com is a place to get an Idea and maybe you can even find a close deal on one there. When I found the engine in my truck a couple of months ago I just called a few local junkyards. 3rd call I made I found onee out of a 2003 with 41k on it. Snagged it up its running great in my truck now. So Id try the local junkyards first..
http://www.car-part.com/