Clacking sound concern 1989 7.3L IDI

[Grumbles]

I've put a video up on my YouTube channel so that more learned folks than me can take a listen. My concern is the clack-clack-clack-clack sound I can hear. It's particularly pronounced when you rev the engine. I just finished replacing all 8 fuel injectors with a set from Pensacola Diesel. I checked to ensure I have no air at any of the injectors, all spurt fuel when I crack them. Truck starts right up and idles no issue. It dies when you snap the throttle, but I suspect that's because I have the original IP and it's probably worn out. Truck has what I think is at least 160k on it, probably more like 260k (5 digit odo).

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Thoughts?

 

[IDIBOBS]

While it’s extremely hard to diag a diesel with a phone recording, especially in this case it really doesn’t sound any different that any other diesel. I’d say with new injectors did you re time the ip? It will need to be timed back down again since the new injectors are not worn out. Worst case by the way you are describing the sound it might be a bad valve guide but those usually one in slowly and get worse over time and since this just changed with new injectors I’d start with timing. If you have your old ones you could put them back on to help narrow it down.

 

[Grumbles]

I know with a worn pump and new injectors the pump will need to push harder to meet the needs of the new injectors right? that would mean advancing the pump? (move towards passenger side?)

 

[IDIBOBS]

Well your pump has advance and pressure. The pressure may need to be turned up and that will effect timing some what as well, but as the pump and injectors wear you have to advance the pumps timing for when it puts fuel into the cylinder. That’s why best practice is to replace pump and injectors. I have a feeling your to far advanced. After you dial in the timing you can adjust pressure for lore or less fuel. None turbo is around 8.5 and turbo is less timing 6-8 depending on motor and what you think is best.

 

[Grumbles]

Well your pump has advance and pressure. The pressure may need to be turned up and that will effect timing some what as well, but as the pump and injectors wear you have to advance the pumps timing for when it puts fuel into the cylinder. That’s why best practice is to replace pump and injectors. I have a feeling your to far advanced. After you dial in the timing you can adjust pressure for lore or less fuel. None turbo is around 8.5 and turbo is less timing 6-8 depending on motor and what you think is best.

If I'm going to fight with timing and fuel flow I might as well bite the bullet and buy a new reman pump and get that installed so I only have to do it once. Guess I'm going to make that purchase tonight unless someone else chimes in with a different thought on what this is and then do battle with it when the pump comes in.

 

[IDIBOBS]

I’d personally try to just back that trimming down just a dimes witch at a time first. Much easier then removing and re installing. Your still hon a need to time the new pump. Save the money first unless you just want a new pump.

 

[Grumbles]

I’d personally try to just back that trimming down just a dimes witch at a time first. Much easier then removing and re installing. Your still hon a need to time the new pump. Save the money first unless you just want a new pump.

I'm doing the ATF tune up right now to see if that will fix the stall on throttle up. After that I can attempt to move the pump towards the driver's side. How will I know by ear when the timing is happy?

 

[IDIBOBS]

I'm doing the ATF tune up right now to see if that will fix the stall on throttle up. After that I can attempt to move the pump towards the driver's side. How will I know by ear when the timing is happy?

It’s hard by ear. But right now you said it’s different than it has been so try knocking it over a little and see if it sounds more like what your used to. No harm in trying. If it sounded fine before the injector swap then you have a base to go by. All I’m saying is give it a shot. You can always put it back it’s just loosening a few bolts.

 

[Grumbles]

It’s hard by ear. But right now you said it’s different than it has been so try knocking it over a little and see if it sounds more like what your used to. No harm in trying. If it sounded fine before the injector swap then you have a base to go by. All I’m saying is give it a shot. You can always put it back it’s just loosening a few bolts.

I did the swap because the truck was blowing excessive white smoke on startup, thought I had blown an injector. That problem seems to be fixed with the new set of injectors, though with what I've read about Pensacola Diesel, time will tell. Before the swap, one more I was cranking the truck up and I heard a bang. After that bang is when the excessive white smoke started. The truck had three different kinds of injectors in when I pulled them so, progress I guess.

 

[Brian VT]

Don't buy a pump or injectors from just anyone. See the Hall of Shame list here.