Okay everyone!

I'm looking for some help. I've got a 2001 Ford Excursion 7.3 with an automatic. It's got 200k on the odometer. It sounded like I have rod knock. The noise would happen just above idle. I figured given the age and mileage that I threw a rod. The noise came with a lot of white smoke out the tail pipe.

I drained the oil with no metal flakes that could be seen. I took the engine out, and took the pan off. There is no metal in the pan. There is no visible sign of a spun bearing. All the rods look in good condition without taking them out and inspecting them.

What was causing that noise?

 

Probably injector knock. Did you do a contribution test?

 

I did not do a compression test and I've already got the engine out. Could injector knock be that loud? And is there a way to check for injector knock with the engine out?

 

my thoughts are that you may not have needed to take the engine out to trace down your knock.

 

Could be as simple as a broken tip on an injector.

 

I mentioned a contribution test of the injectors. Yes injector knocks can get very loud.

 

Anybody has any audio file of what injectors can sound like when they go bad?

 

[QUOTE=erickk120;19066452]Anybody has any audio file of what injectors can sound like when they go bad?[/QUOTE

Sounds a lot like a rod knock. I can't imagine any digital recording being able to really reflect the difference between a rod and injector knock. They might sound difference from each other, but I don't think they'd really help someone in deciding between the two when listening to their engine.

 

When there was no metal in the oil that should have been the point to stop and reconsider before pulling the engine, especially with only 200K miles. One option now would be to send the injectors out for testing. There might be a smarter way to figure this out, but I don't know.

 

Broken injector tip or even a shorted out injector harness can cause loud noises. Check you your wiring.

 

Bent pushrod will make most people think rod knock.

So can broken flexplate.

Catastrophic failure is unlikely.

Post a video if you can.

 

Smoke and signs of hydrolock on cold start could indicate broken injector nozzle spring. This allows fuel to trickle in cylinder(s) when engine is not running and effectively overfuels while running. Dropping fuel BEFORE TDC of piston and creating a ‘knock’.

 

My flexplate seems perfect, no visible damage, no teeth missing, no major scratches etc.

I didn't see anything wrong with the pushrods.

Do you know of anyplace to get an injector tested?

 

Man, sorry you already pulled the engine. Sounds like your first diesel. These FTE brothers know a lot about these 7.3s, so keep us posted. Since you have the engine out I would suggest pulling glow plugs and injectors to assure a rip hasn’t broken off a glow plug and damaged a piston and you don’t have a cracked injector cup. With all that work done at this point it’s a good time to check out numerous items before putting engine back into the X, such as rust on oil pan, any mods to top of engine such as turbo work, new up-pipes, check for oil leaks on top of engine, etc.

Good luck,

 

I missed the engine is already out... Wow!! (Pre-coffee reading comprehension = weak...)

Ok. Let’s back up and punt.

These engines almost never see main and rod bearing failures or other issues with rotating assembly - except cracked pistons. Oil pressure is required to fire the injectors so no oil pressure means no running engine. Of course contaminated oil, etc does happen.

Before pulling engine, we would have liked to check blowby and those pushrods....

The flexplates crack right behind the plate where bolts go through. You’ll have to remove flexplate to see damage. I promise, a failure here can sound more than catastrophic and presents differently depending on the failure mode (where crack is)

Likely you’d spot a bent pushrod, but it’s possible for one to bend and stay in place. When bent just a little, it can move rocker but not enough to work right. This is easy to see with engine running.

You can easily spin the engine over to compression test using the transmission adapter and the starter bolted to the block with engine resting on the ground. A boroscope with small enough lens to fit through injector hole or GP hole might help find big problems like beat up piston top from broken GP, injector nozzle or foreign debris.

There are places you can send injectors out to and have them bench tested if you don’t see obvious problems.

Dang. I sure wish we had figured out what was wrong before pulling engine........