The is my 7.3L running. I just bought it so I'm getting used to the sound. The engine seems to run ok but it got a really loud knocking sound that I'm not sure is normal. I wanted to get a second opinion. What do you think?

If this is normal what the heck could it be? Its not the sound the injectors make that's for sure. And it doesn't sound like normal combustion either.

 

Sounds like injector knock.
How many miles?
What type/grade of oil are you using?

 

125,000 miles. The right bank of injectors have 2,000 miles on them. Oil is Rotella I forgot the weight. The dealer did an oil change after replacing the injectors.

 

That's definitely injector knock

 

Thanks for the info. I'm guessing I need to stop driving the truck now right?

Whats my diagnostic procedure from here on out? Start with the easiest and work my way down the list? Maybe unplug each injector with it running to isolate a cylinder? Or test fuel pressure?

 

Next step would be to check fuel pressure. If all is good then pull the valve covers to check uvch and for loose/lifted injector

 

If the dealer put those in id have them be fixing the issue on their dime and time... Yes that sure sounds like injector knock, sometimes the audio on phones make it sound louder than it is. If that was a cold start and it disapates then there shouldn't be anything to worry about. is this right after the injectors were installed? How many miles since install?

They should warranty parts and labor if they did the work.


If you did loose you mechanical pump. Get a new one here for 100$. http://www.riffraffdiesel.com/mechan...uel-lift-pump/ It will take all of an hour for a first timer to install.... the dealer will be upwards of 400$ to do the work...

 

Ok gentlemen, school me. What is injector knock, and what is it's evil outcome?

 

Well there are many causes outside of the electrical components.

1. Low fuel pressure, no fuel pressure, air in fuel
2. Air in HPOP system after an injector swap
3. Internal injector failure
4. A broken nozzle which will cause the truck to emit an enormous amount of white smoke
5. Cylinder Temperature
6. Oil viscosity

These will all cause what some call injector knock or clack, or a dieseling clack. 90% of the time its a fuel or oil delivery issue if not related to a cold start.

I'm sure some will add more

 

I bought this truck in CA and drove it home to TX. So I cant exactly take it back to the dealer for cheap. They blew me off and said "It's and old truck" and said my knock isn't related to the misfire they fixed before. Big help they were...

I drove the truck back with this knock because I thought that's just how they sound but then became concerned after hearing one that didn't sound like mine. I hope I didn't do irreversible damage to the engine. I'm replacing my DMF right now so to have to do an engine as well would really hurt my wallet.

Here's an update: Changed Auxilary fuel filter. No change in sound. Ordering a fuel pressure guage next.

 

I'm not sure if this is related but my truck has a hard start issue too. Usually starts on the second crank. I'm ordering some diagnostic tools to help narrow down what the issue could be.

 

OBS's didn't come with electric fuel, sounds like you have efuel because of the filter being mounted on the frame.

 

So, is it the mechanical components in the injector making noise, or the cylinder being unhappy with poor fuel delivery?

What type of damage is resultant?

 

If truck is a late 95 you mite have an obd2 port under left side of glove compartment. You can buzz test the injectors if there

 

Low fuel psi, air in fuel system or loose injector causing injector knock will damage the injector.