hello everyone,
i have a 1999 ford f250 5.4ltr with a wierd engine noise .for starters the sound is really resonating(very pronounced) from the passenger side catalytic converter.at idle i get a tock,tock noise not a deep knock noise.for starters i took off the belt and it was still there,brought it to 4 garages and was told it was a piston slap,main bearing,con rod bearing......i then disconnected the injectors one by one and the noise almost went away on the 3rd cylinder on the passenger side.when im driving very slow i can hear it speed up a bit then it goes away and comes back when i come to a stop.i did a brake stall and it sped up but then is a tick tick noise under load not the tock tock noise.my oil pressure stays always high and i have since put 600kms on it and the noise never changes its always the same.no lights no codes
any thoughts would be appreciated

 

This is difficult read, - might wanna practice up on punctuation and capitalization. Could receive more help that way, you never know.

Also Km's to Miles or both.

 

Sorry about that.My truck has 144,000 kms

 

Very funny.

 

Sounds like Piston Slap to me as-well, if it went away after disconnecting #3.

You took away fire/combustion which makes it a different world inside said cylinder. Slap is a pretty common problem.

 

thanks jbrew but........
By removing fire/combustion doesnt the piston continue to keep going up and down?
or is the slap caused by detonation? or the wrist pin

 

Are you serious ? It better if the others are. Yea, it changes things up enough inside, like I said above.

You said the noise is coming from your cat, so why did you remove the serp belt? If you can't pin-point a noise, use a long screwdriver or something as a stethoscope to assist.

Slap/noise seems to be is echoing thru the exhaust correct ? I can't hear it from here of course, but the other mechanics could and from your description, -they're most likley right.

A bad PCV valve can make that noise, but they would have discovered that, just as they would a bad cat.

The mains don't usually go out in these engines or leak.

Maybe someone else can think of something different it can be.

Good Luck and welcome to the site.

 

I know a lot of my responses for "knocking, pinging and slapping" noises are to check the passenger exhaust manifold. It's just that I've owned 3 2v 5.4L trucks, my dad has one, my uncle and one of my co workers and I'm not exaggerating when I say that every single one of them have or have had the passenger manifold leak. It's worth looking into before you tear things apart. It's common for the studs to rust out and break off... then the metal gasket flaps around. Sometimes its on cold starts, other times it can be intermittent. It can resemble piston slap to an unknowing ear.

 

Your oil pressure remains high because it's an "idiot light with a needle". It's not a real gauge at all. Do you ever see it go up and down when you're idling or running at 80 MPH on the freeway? It's a dead giveaway when it always stays in the same spot. Ford thought people would be happy and sleep better if they thought their oil pressure was always good, so they made it happen. If it ever does go down,call a tow truck because it only takes about 4 lbs to operate it, less than that it will go down just before things go BANG! The noise should go away when the cylinder isn't firing because the piston isn't being driven down by the combustion in the cylinder. It's just coasting along for the ride, the piston isn't tempted to do the flip-flop that a short skirt piston is when it's being driven down by combustion. There are a lot of engines that have piston slap from the time they roll out of the factory door- think Chevy, it's pretty common with square displacement, piston doesn't get a chance to stay straight up and down in the cylinder.

 

Ok so from the sounds of things I have a similar problem, I also pinpointed the noise to the cat. With a mechanics stethoscope aka a extension, I found a tsb for the cats from ford, rhythmic engine knock. Was the symptom and like the original post mine is louder when could and gets softer when the engine is warm, the knock is inaudible when driving you can hear it best at idle next to a building or parked next to s another car it has no effect on the running of the truck it mad this noise at 7800 mile and still makes it at 111789 miles. I to have had mechanic friends tell me it was my oil pump fly wheel rod knock can phasers exhaust gasket s. Please find the tsb and read it and tell me if it matches your issue I'd love to get ride of it cause if one more guy say hey man your trucks got an engine knock I'm gonna lose my mind.