7.3 IDI Knock

[southpole560]

Hey guys. I'm new to this forum and thought I'd post this here. I have a knock on my turbo'd 7.3 IDI. I've checked the injectors, replaced the lifters and pushrods, and set the injection pump to stock timing (lined the marks up). Now here's the thing, when I crack the injectors the knock is still there EXCEPT when I crack the #5 injector. The knock gets quieter but is still present. You can hear it but it's almost like it's gone. I have swapped it with another cylinders' injector and it's the same thing. It sounds like a metallic knock. Could this be the wrist pin hitting the rod? The sound comes from the top of the engine. The odometer reads 348xxx miles. I have drove it like this since it was at 343xxx miles. The knock sounds exactly the same. Oh and when I let the truck sit for 2 days without starting, the next time I start it the knock only appears after 15-30 seconds after the engine is started. The knock also goes faster with the rpms and you can hear it through every range of them, even on the freeway but it is not as noticeable. Thank you in advance for the help. I have done quite a bit of research on multiple sites including this one in regards to that knocking.

 

[IDIoit]

i would assume that a rod bearing is done for before a wrist pin.

we need more info.
turbod? when was the last oil change? what oil are you running?
did the rollers on the lifters on #5 look to be damaged?
i would break out a stethoscope- one of my favorite tools, and determine where the knocking is coming from.

welcome to the forum, im guessing Marine?

 

[southpole560]

Yea it's a 93 factory turbo engine. Funny thing is, is that the truck is a 92.5 and the engine is a 93. probably their first turbo'd model for the IDI. Last oil change was when I first got it around 343xxx miles. I did the oil and filter change. Used a motorcraft filter and rotella 15w-40 oil. The rollers seemed perfectly fine on the #5 lifter. I did use a hose to hear the engine sounds before but I couldn't quite isolate the sound. And yes I am sir

i would assume that a rod bearing is done for before a wrist pin.

we need more info.
turbod? when was the last oil change? what oil are you running?
did the rollers on the lifters on #5 look to be damaged?
i would break out a stethoscope- one of my favorite tools, and determine where the knocking is coming from.

welcome to the forum, im guessing Marine?

 

[IDIoit]

Yea it's a 93 factory turbo engine. Funny thing is, is that the truck is a 92.5 and the engine is a 93. probably their first turbo'd model for the IDI. Last oil change was when I first got it around 343xxx miles. I did the oil and filter change. Used a motorcraft filter and rotella 15w-40 oil. The rollers seemed perfectly fine on the #5 lifter. I did use a hose to hear the engine sounds before but I couldn't quite isolate the sound. And yes I am sir

DONT CALL ME SIR, I WORK FOR A LIVING!!! hahaha
people here have mixed feelings with rotella, some say its great, some say their IDI's drink it like a bottle of whiskey while on leave.

a hose wont really work, a long screw driver is better but nothing beats the proper equipment.
you can find them on e-bay for 10 bucks.
or go visit medical, and stuff one in your cargo pocket.
there not ment for just MRE's lol

thanks for serving! Seabee vet here.

 

[freebird01]

my guess is you have a ******* injector (stuck open) on that cylinder....

and yes...all the IDI's ive owned tend to eat rotella like a fat kid eats cake...

i stick with delo or delvac

 

[southpole560]

Haha I've heard that phrase so many times lol. Rotella has seemed to work alright. A little bit of oil consumption but not too bad. I took a video of the knocking sound and I will upload it a little later. I actually used a pool vacuum hose to listen to the sounds. It didn't sound like it was coming from the bottom end. If it ends up being a connecting rod bearing, do you think I could get away with replacing it or would I have to do a rebuild? And Thank you for your service!

DONT CALL ME SIR, I WORK FOR A LIVING!!! hahaha
people here have mixed feelings with rotella, some say its great, some say their IDI's drink it like a bottle of whiskey while on leave.

a hose wont really work, a long screw driver is better but nothing beats the proper equipment.
you can find them on e-bay for 10 bucks.
or go visit medical, and stuff one in your cargo pocket.
there not ment for just MRE's lol

thanks for serving! Seabee vet here.

 

[southpole560]

I have had to add a few quarts of oil over the 5 thousand mile period since I've changed it. I added delo and it seems to have not been consuming it that much so I'll probably use delo next oil change.

my guess is you have a ******* injector (stuck open) on that cylinder....

and yes...all the IDI's ive owned tend to eat rotella like a fat kid eats cake...

i stick with delo or delvac

 

[IDIoit]

that phrase is widely used in the enlisted croud of all branches in the armed forces lol.

i would get a new set of injectors, it sounds like its time for some.

there are members here that sell a matched set, typ4 has some in stock.
so does Mel, @ www.conestogadiesel.com

use your perdeim wisely! lol

 

[DaytonaBill]

I had a persistent knock from my original engine.

Did it sound like this? https://www.youtube.com/watch?v=WR1I3cORg2Q&feature=youtu.be

 

[freebird01]

On rotella my 7.3 w/ 126k on the clock would burn 4-5qts in 3000 miles....

Switched to delo and delvac it went to 1/2qt in 5000miles...

 

[southpole560]

I really don't think it's an injector. Like I said, I swapped the #5 injector with #6 and it was the same thing. If I crack the injector all the way, the sound gets a lot quieter but you can faintly hear it still. And there is no smoke either. Just a small puff of white smoke on a cold start but thats it. Here is the sound my truck makes. I took this video a little earlier.

https://youtu.be/ewzT0MdFmr8

 

[chris142]

On rotella my 7.3 w/ 126k on the clock would burn 4-5qts in 3000 miles....
...

Mine does that with any oil! It really hated delo.best was Walmart supertech and delvac 1300 a close 2nd.

Rotella may burn faster for some reason but its a great lubricant. Its not the cause of your knock.

 

[icanfixall]

My wag is an injector has failed. You have enough time on the set you have now so I suggest changing them. Any injector over about 150,000 miles is considered worn out.

 

[IDIoit]

you damn jarhead (with all due respect intended from a veteran)
open the hood.
inspect exhaust manifold carefully for soot.
around exhaust ports.
all around exhaust manifold.
if you are 100% in your mind that its not an injector.
i suspect either an exhaust leak, which is my drunk unprofessional opinion.
or a collapsed lifter.
a rod knock or a wrist pin will have a lower frequency sound.
definitely AFTER the short block issue.
your lower end sounds ok.

if it is a valve, or a spring, take care of it ASAP, and dont drive it.
the slugs can take a beating to a certain extent.
but do not royally F it up.

do i need to break out the UCMJ on that ass?

 

[Waystro]

Like said it could be a injector
it almost sounds like the top end isn't getting lubricated very well