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one lifter making noise

Hey WarWagon The engine cranks evenly, the injector knock fades in and out mostly - sometimes can hardly hear it. Sometimes really loud knock. Once when going down the on ramp to merge with traffic - a huge cloud of black smoke was behind me (empty weight with no noticeable knock). The last trip when I brought it home from the shop I did not see any smoke after startup - engine was warm after test drive. Also very little if any knock.

When starting in the cold, 40 degrees F or so - small puff of dark smoke that clears up. (normal would be no smoke) The last cold start it seemed like two cylinders were missing for the first 3 or 4 strokes then smoothed out and ran fine. When the injectors are proper the glow plugs were only needed on cooler or cold days. I wait for the glow every time with the old original worn injectors and the new ones.

I did haul one load of gravel from the quarry and it pulled fine with no smoke up hill, stayed in overdrive @ 60 mph the whole trip (30 miles) with the new AC injectors. Started big injector knock after pulled off the highway onto back roads. But that faded away except for a small knock sometimes.

It has a new air filter and I covered the intake in the fender with 1/4" hardware cloth and have not had a rats nest in the intake since.

All this poor mileage and smoke/missing on cold start only happened after I put new nozzles in the original injectors. They started with no smoke and ran fine but after about a tank of fuel when those acted up I had a shop install new AC Delco injectors - they did the same as the ones I put the new nozzles in. Ran fine for about one tank of fuel then started knocking and smoking (not to mention 10 mpg instead of 16, 13 loaded with the worn original injectors) I suspect I could put the original nozzles back in and get back to how it was or better if I use some polishing compound on the pintle and seat. It was just starting to put out a puff of dark smoke on cold start at that point (never had a cyl. misfire). But I would rather have new 'cause working on it is not my main ambition in life... ;-)

I really suspect the injectors because the originals had about 130 K miles on them and they were better than the china made nozzles and where ever the AC injectors were made.

I did not notice a difference in mpg when I removed the vac pump, but I have had zero problems with the spring, I only removed the vac due to it failing... the engine has been chipped in addition - no other mods. Well, unless you count the crossover larger dia. pipe - but that rotted off and had to be replaced in any case. The boost runs 10 lbs max. with no smoke since '05 when I installed the spring.
 
I would suspect in this order:
Align the truck ... wait: you confirmed problem with a wheel bearing failure. This may resolve the MPG problem alone.
Look for fuel leaks. Diesel fuel will evaporate off the exhaust manifold. The return lines can be a real PIA to deal with and leak especially if they decided to take a shortcut and omit the return line clamps. It's a gamble to skip the PIA clamps this despite claims some modern hose kits doesn't need em.
Do a timing learn procedure. Higher pop pressure from new injectors retards timing. Old worn injectors have a lower pop pressure and start injecting fuel sooner. Your ECM will eventually do this on it's own.

The nozzles should be from India now. I have had zero luck with China nozzles. Good parts are very hard to get now.

Is the knock still on the #4 cylinder? Does it follow the injector if you swap the injector with another cylinder?

The harmonic damper on the front of the engine, there are two rubber dampers on the front of the crank. Either or both can make knocking noise. A cracked flexplate is also a source of a knock.

You need to verify the glow plugs are all working. IR temp gun and look for ones that are not getting the cylinder head area by them warmer after cycling. I did not read anything about new glow plugs with new injectors. Are these the original glow plugs? I suspect #4 glow plug may be INOP...
 
New injectors from Leroy are made in India in what is suppose to be a Bosch factory, or, to Bosch’s specifications.
The set I got did not test well on my tester, sent them to a shop that is familiar with the 6.5 and they all came back perfect. Spray pattern, holding pressure without leaks and everyone was exactly on 1950 PSI on the pop test, chatter too was very good.
 
Align the truck - I will check the mileage next time I go to town.....

Look for fuel leaks - I replaced all the rubber hoses on top of the engine, only the return to the tank is original. It still looks OK - no cracks or abrasion visible. All have clamps.

zero luck with China nozzles - That is the same result I had with my china nozzles.

After I got a pressure tester the results were all with no shims in place - only heavy washes on the springs as original! I had a 400 lb diff on one of the china nozzles (2100 lb or so) 3 were at 1750 the rest about 1850. I have not tested any of the AC injectors currently installed. I plan on removing and testing those at least the ones I do not have to remove the turbo for at first. I am contemplating getting new injectors or nozzles after getting some kind of verification they are functional. I wonder if the AC injectors currently installed were built with china nozzles?
I am leaning toward getting some good nozzles and shims and going thru the original bodies with those new parts before I take it apart again so I have better nozzles and pop pressures to install at the same time...

knock still on the #4 - I did not swap injectors - I replaced the knocking one with a rebuilt from the auto parts store. The knock was gone completely. It took a few more trips for it to return - sounded like it was on the other side of the engine. That is when I had the shop install the new AC inj.

harmonic damper - would not that be a more consistent sound? Would it change with an injector change? None of these symptoms were present until after the original injectors were replaced.

are glow plugs all working - These are the original glow plugs, starting seems to be the same with the new (new nozzle and brand new) injectors (both sets) as it was with the original worn high mileage set. If you let the glow plugs glow and then start after the idiot light shuts off, it starts right up. The volt meter drops to the same value as always when glowing, I am not sure you can see a diff if only one has failed. I will run the thermometer out and see what it says. I did crack the nut on #4 with the new AC set installed while it was rattling with no difference so I do not think it was the same cyl.

I definitely will look into new parts not from china!
 
First off, your running the original glow plugs on a 93 truck?? they need to be replaced and very soon!

Harmonic Damper, Mine went and did not make any noise. I just happened to be laying under the truck looking for something else and saw the outer ring of it had spun. when I pulled it off, the outer ring and center section just slipped off very loosely. it will throw the engine off balance and can cause "knocking" internally plus major damage to the crank and mains. craw under there and look very closely for any sign of issues. it is recommended to replace the GM one every 100k miles with only a GM replacement. if you get aftermarket from the auto parts, those are only good for maybe 30k miles. this thing can kill your engine in an instant. broken crank and or cracked main webs on the block.

as for the injectors, I am curious as to the condition of your fuel. wondering first what type of fuel your run and if you have some contamination that might be fouling injectors. get you a clear 32oz bottle or mason jar and pop off the fuel line going to the IP, drop it into the container and fill it with using the lift pump. take a photo of the fuel in the clear container and post it up for us to see and verify this is not the issue.

By all means if you pull the injectors, do post the results on testing them. ideally have a helper use your phone to record a video of you testing each one you pull showing the spray pattern and pressures they pop. then upload to YouTube, link that video here in a post so we can all see and help determine what might be the issue here as well.
 
For what it's worth I've been told by an injector guy that Bosch nozzles that went to India are worse than the china ones. Apparently there's nozzles being made in Italy that are the best option at the moment. I think the Italian company is Bosio but can't find any way to source the Italy made ones specifically. Probably better luck going through a diesel supply shop.

I've also heard that some mercedes engines use the same nozzles in their injectors. Over at mercedessource.com German made injector nozzles are being sold for Mercedes turbo diesels, so that may be an under the radar quality source given all the other junk out there.
 
Yes, the glow plugs are the originals when the truck was built in '95.

I will make sure and check the damper... I have about 130 K miles on it.

The fuel will probably have a red cast as it is usually farm fuel. I only use highway fuel when I am out on the roads. It might be clear though as I have not been using it on the farm much due to all the working on it. - none of these issues were present before I installed Injector nozzles using fuel from the same tank. I will check it just in case!

I tried a gallon glass jar but the reflections and the curved shoulder on the jar interfered with a clear view of the test spray pattern. Then I used a plastic 'can' with straight sides, but still had the reflection issue. My workbench does not lend itself to just clamping or bolting the pressure tester on. So I cut a 5 gal. hydraulic fluid bucket so the spray pattern is visible and painted it flat black inside - that seems to work. Tomorrow I will start making videos, This and one other forum is the only social media I am on. But I do still have a rented server so can post whatever I need on that.

Someone with experience looking at the pressures and spray pattern will have a better idea than I would!

I will definitely check out the Mercedes idea - I have seen that those look like the 6.5 on the outside at least...

My original injectors had 304 inside, made in Germany, The replacements had 304 written on them but not made in Germany.
 
Unless you have a mechanical DB2 IP installed, I have been told that running red fuel in the DS4 IP can cause a lot of issues for the electronics. no known issues that I'm aware of for the injectors though. others can chime in on this.

try a glass mayo jar for watching the spray pattern and to catch the airsolized fuel. you can do it out in the open to see it, but make dam sure where you pop the injectors is well ventilated. airsolized diesel and any spark (someone flipping on a light switch) can make your garage go BOOM! flash fire!! You'll be cleaning out the seat of your trousers!
 
Steak&Eggs said:
These are the original glow plugs, starting seems to be the same with the new (new nozzle and brand new) injectors
Click to expand...

IMO glow plugs that are not self regulating are a ticking time bomb! Even when somewhat new a controller problem can turn them into engine damage debris. Been there done that with a "Late Model at the time" 1988 6.2L NA that ate it's glow plugs in like 1990. There isn't a set life for glow plugs so much as the new technology self limiting plugs are somewhat safer than the old ones that are known to swell up and fail esp. from glow plug controller problems staying on too long or otherwise overheating them.

ACDelco 60G's are the recommended plug now. Bosch makes self limiting as well, but, there are a couple of failed engines over them. Purchase from a reputable source in case one does take the engine out.

My thinking is if the #4 plug has failed it may be the source of a knock from being impacted in a piston.

My first set of China rebuilt injectors had one, in #7, carbon up bad.

Extreme carbon build up on 1 injector. What is going on?

Here are 2 pics of the #7 injector. There is a large build up of carbon on one side of it. See Arrow. This is one of 3 suspect injectors where it looks like there are larger shims than the others have. The area with the arrow is further up on 3 then the rest. #1 injector is wet and this...
www.thetruckstop.us

The engine had scuffed and cracked #1 piston.

Shop re-checked and cleaned them. (Maybe even replaced a nozzle I don't recall) Later on different engine we dropped in: at 30K miles they were sticking "open" and blowing smoke rings out the exhaust while destroying the starter overrun clutch from Hit-miss-miss-hit while attempting to start.
 
Last edited:
The red diesel is just a red dye added that doesn’t affect operations UNLESS the dye is so dark (too much) that it messes with the optical sensor.

If glowplug or similar damages piston- the knock will forever be there.

Can’t remember bad cylinder- for example call it #4 and all others are good:
The idea of switching two injectors is not just make cylinder 4 better but make cylinder 1 mess up. This is like a double proof if you will. Swapping in old injectors doesn’t show that it is the old injector problem because if it is inconsistent- now is the newly installed original injector having issues? We don’t know. But swap 1&4 then cylinder 4 never has a problem and cylinder 1 now does have an intermittent problem- we know it is the injector.

Mercedes Source has no interest in 6.2/6.5 and has shot this down multiple times before.
 
I disconnected the fuel going into the IP and used the lift pump to put it in a glass. Looks good to me...

We use red fuel in all the farm equipment for many years - no problems so far!

The IP has a green tag. My garage is the great outdoors in my driveway.

ClearFuel1.JPG

I did the spray pattern test, chatter, and I thought a leak down test on the china nozzles, but after I replaced all the new china nozzles with the original worn out Germany nozzles I started running the same tests. And got confused, the china nozzles had all but one leaked down pretty quick - then the German nozzles all did not seem to leak down at all. Hmmm, that did not compute esp since the spray patterns and chatter all were worse than the china nozzles. So I picked the last one I tested that was still connected, ran it up to max pressure and closed the valve on my new tester. The pressure held and was rock solid - it did not go down any that I could see... I then removed the injector from the line completely - the pressure did not drop. Great - so now all my previous tests do not include a valid leak down. I made video of all of them.

I sent a message to the vendor of the pump - it is an AG professional from India. There is only one knob on it. I did not get an instruction manual but I did not worry because 'how difficult can it be?' I guess I found out - either it is broke or I sure do not know how to use it! I hope the latter is true because that is the easy (and fastest) one to fix.

I also realized I have to acquire all my tools to work on my server due to the fire - all my software and hardware tools are gone. Drat!

I did notice all the china nozzles sprayed and chattered. None of the 5 tested originals chattered and the pop pressure was much lower and the spray was harder to maintain. It took much more force on the handle to get a spray, I guess due to it trying to spray before pressure reached the higher pop off value.

One thing different on the china nozzles (I cleaned them up before the test) 3 nozzles had carbon built up on the outside of the nozzle between the nozzle housing and the body of the injector. I could see no difference in the cupped washers that are supposed to stop carbon entering the injector. (at least that is what I think their purpose is)

So everything is up in the air right now until I get the pressure tester resolved. I suppose I will work on getting my server up or some other way to get the videos online!
 
Sounds like the way your tester is constructed is the gauge is installed between the pump and the valve, then the injector when it should be the other way around. the gauge should be between the valve and the injector.

if you pumped it up and closed the valve and it held pressure, that would mean the pump is holding. just for this time try leaving the valve open and see if it leaks down since the pump is holding.

the main issue we are thinking here with the injectors is the pressure at which they spray and the spray pattern. if all checks out good (even pressures and pattern) then I would be looking at the pistons or possibly the valve train as an issue. time to do a compression test before tearing it down.

after a compression test, then it's time to first pull the valve covers off and inspect the rocker arms, shafts, and nylon buttons holding the rockers. also the valve lash or slop when piston is at TDC (looking for possible collapsed lifter or other valve train issue. then if all looks good, it's off to using a tiny inspection camera to look into the cylinders.

a compression test will point you to where to look if all of the (current) injectors check out on the test bench.
 
I’m just used to doing the stanadyne & gm procedure.
Ya go in that order and process, it eliminates the other stuff in rapid succession.
A feller can run a bunch of tests and try anything ya want. It’s just that it takes a lot longer to do it and it can mis one or two details that later you have to come back around and test for.

Clear tube air test. Then because one cylinder misfire is suspected - swap the questionable injector with a proper working one from the engine- this identifies injector vs cylinder specific components. All 8 Compression test and cylinder leak down test.
Fuel volume comparison test.
This process also attacks the most common failures before least common ones.

Removing and testing individual injectors, swapping in and out other used injectors not running in the engine without failure while the issue is occurring, checking left front tire air pressure. All well and fine. Eventually you luck out and discover the issue, or ya go back to square one and follow procedure.

Sampling fuel and all is a proper normal step after verification of no air in the system- WHEN all cylinders are misfiring. But only one means it is not the fuel by default because the 7 proper working cylinders are getting good fuel.

If the glow plug(s) were the issue, the problem would not come and go. It would be there when cold, go away when warm. That is not the description given. Damage from the glow plug would be more consistent.

Knocking lifter was instinct as given in title. That is still a possibility. But the fact that it all began with installing these injectors tell me, 98% chance it is the injectors or something directly related. the swapped position injectors rules out multiple issues first and hence needs doing. This thread is old enough I can’t remember if other normal procedures were ruled out because of the #4 cylinder being determined as issue- like ruled out air intrusion.
 
the gauge is installed between the pump and the valve:
I contacted the seller and they state the valve is between the gauge and the pump, so closing the valve leaves the gauge indicating pressure but with no relation to anything else. ? Seems an odd way to go about it. I suspect leaving the valve open should indicate the leakage of the injector - perhaps I should try that before I go modifying the pressure tester setup. Might save me some time, but if they all leak down so fast I can not measure it I will put in the secondary gauge and valve.

The reason I started closing the valve is there was no pressure held when I quit pressurizing with the pump handle (on the first few injectors I tested) and initially it would leak down some amount - some more than others. So it seemed like it was doing what I thought it should. As I did more tests it started holding (perhaps due to wearing in of the valve seat?) Then I questioned what I was seeing, upon disconnecting the injector with no pressure change I realized I did not have a clue as to what I was doing.

In inspecting the pump I noticed a weep hole in the side of the pump, when the pump was tilted fuel ran out of the weep hole (not much).

I have another gauge and valve I might put these in line with the injector and read the pressure in the line and have the ability to close off the pump so only the injector and gauge are connected. (if my test above warrants) Just in case the pump allows some seepage back into the pump. If it don't leak I do not need to use the valve. Unfortunately I can not locate a 14mm 1.5 coupler to connect things together but I do have a fuel line that will work, it might look a little funny. But it should get the job done I do not wish to wait around for parts any longer than necessary.

swap the questionable injector with a proper working one from the engine:

That is the fail safe way to isolate the problem. I did not swap the inj. out - I replaced the one that was causing the issue and it did not return with the new inj. Until about another tank of fuel and it seemed to be on the other side of the engine. #4 was the noisy one until the inj. change but not since.

I am not a mechanic and do not know the procedure so am at a disadvantage in that area!

Subsequent test proved it to be injector related and not a lifter issue.

I will know more after some more testing with the pressure tester.
 
one way to tell on the injector leak down test while using the pressure tester is to pump it up, make sure the tip is dry (no fuel) and CAUTION do NOT for any reason put your hand anywhere near the injector tip while under pressure.. put something under the tip on the bench like a white paper towel. leave it pressured up and wait.... when the pressure drops look to see if the injector tip is wet. if not, then it's the test pump leaking down.

I do not know the time frame to say weather it's good or not. my guess would be leave it for 15 minutes under pressure and see if the tip starts dripping fuel on the paper towel.

again the main thing your looking for here is the pressure at which it releases fuel, the spray pattern (nice wide mist or a pissing stream) and if it continually dribbles fuel as you pressure it up. mark each injector with the cylinder # as you pull them and post the results on each. then we will go from there.
 
OK, I got the manual for the tester, its all in how you use the handle! The shut off for the gauge is to make the gauge last longer.

pop pressure, chatter, and spray tests all perform like they should. The leak down test is different.... With the gauge closed off the inj is pressurized but just under pop pressure. It is supposed to hold for 10 seconds and not drip.

In my case the handle went all the way down to maintain pressure and then bottomed out after about 1 or 2 seconds. I did it again and checked the inj - the tip was wet but no drips fell.

So I sent an email to the mfg and asked if that was normal? We will see what they say.

All the testing I am doing are on the original worn out inj and the new china nozzles I installed. The china nozzles chatter and spray (but three of them were clogged with carbon, none of the originals were) the originals do not do so well - no chatter and the spray pattern is pretty bad. They are definitely shot. Even though they ran with no inj knock.

When I find out about the leak down test I will remove the new AC Delco inj from the engine and test those.
 
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