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-   -   Injector knock, is it something I’m doing?? (http://www.peachparts.com/shopforum/diesel-discussion/422769-injector-knock-something-i%92m-doing.html)

JHZR2 06-23-2024 11:29 AM

Quote:

Originally Posted by Diseasel300 (Post 4319118)
Unless you have serious chain stretch from extreme lack of maintenance, IP timing and base engine timing are the least likely to be your issue here. 60x engines just don't eat chains like the 61x engines do and there's no offset keys to adjust cam timing either. I've serviced 603's with 300-400K on them and the original chain with 1-2˚ of stretch and left them well enough alone.

I would have hoped that my previous reply about the delivery valve leaking would have been heeded, but nobody ever listens to someone with experience, so why am I not surprised? There's a reason I rarely contribute to this forum anymore. The injector isn't the issue, it's delayed or improper combustion. I've dealt with many 60x engines with this noise and DV's generally improve or eliminate the issue. Newly rebuilt injectors shimmed to the correct pop pressure always seem to exacerbate a leaking DV compared to an older worn/weak injector. The older engines with the "vertical" injection prechambers are far noisier and always have a certain degree of a metallic "cackle" at idle. Some degree of knock is to be expected and has to be tolerated.

In this case, you have a combustion problem, likely a leaky DV or worn DV seat. Air in the return lines is normal. You don't normally see it with the black/grey rubber ones and it takes a LONG time for it to work its way out. The leakage through the return/leak ports in a well-lapped injector is very small, so the flow through those lines is minuscule.

Actually, I do need your advice. But with three kids and a full time job, I can only mess with this so often. I do appreciate your current and legacy posts, BTW.

I just received on Saturday, the spline socket and a set of DV washers and o-rings. So that is going to be another thing I work through. It’s excessively hot here so starting on that, amidst other stuff, just wasn’t going to happen. But I met up with greazzer in Delaware on Friday when he was passing through, so got some injectors, and was just excited that maybe there could be a difference. Remember that one time I put another injector in and it seemed quiet…

The TC wear is less than half a degree.

Anyway, thanks for your help, please don’t take anything as if you’re being ignored, I for one sure appreciate it!!

JHZR2 09-07-2024 11:28 PM

Quote:

Originally Posted by Diseasel300 (Post 4319118)
Unless you have serious chain stretch from extreme lack of maintenance, IP timing and base engine timing are the least likely to be your issue here. 60x engines just don't eat chains like the 61x engines do and there's no offset keys to adjust cam timing either. I've serviced 603's with 300-400K on them and the original chain with 1-2˚ of stretch and left them well enough alone.

I would have hoped that my previous reply about the delivery valve leaking would have been heeded, but nobody ever listens to someone with experience, so why am I not surprised? There's a reason I rarely contribute to this forum anymore. The injector isn't the issue, it's delayed or improper combustion. I've dealt with many 60x engines with this noise and DV's generally improve or eliminate the issue. Newly rebuilt injectors shimmed to the correct pop pressure always seem to exacerbate a leaking DV compared to an older worn/weak injector. The older engines with the "vertical" injection prechambers are far noisier and always have a certain degree of a metallic "cackle" at idle. Some degree of knock is to be expected and has to be tolerated.

In this case, you have a combustion problem, likely a leaky DV or worn DV seat. Air in the return lines is normal. You don't normally see it with the black/grey rubber ones and it takes a LONG time for it to work its way out. The leakage through the return/leak ports in a well-lapped injector is very small, so the flow through those lines is minuscule.

Replying again to let you know that I have taken your advice and did the DVs today.

Removing the intake is the biggest hassle. Not hard, just a hassle. DVs were easy. A mess, but easy. I used compressed air and cleaned as best as I could.

https://i.imgur.com/NZmlA0kl.jpeg

O-rings were hard as would expect.

https://i.imgur.com/ZTbUXksl.jpeg

And the old crush washers had a slight wear ring

https://i.imgur.com/wRUIOCZl.jpeg

https://i.imgur.com/bkdC2xUl.jpeg
https://i.imgur.com/9t2F67gl.jpeg

https://i.imgur.com/RmsW02Ml.jpeg

Torqued them as per the instructions.

https://i.imgur.com/ulkT4JGl.jpeg
https://i.imgur.com/J5bMV7zl.jpeg

https://i.imgur.com/SSlrMfQl.jpeg

It took some cranking to get the air out, but it worked out ok and fired up. It still has a knocking sound, and what I’m seeing is a lot of more frothy bubbles in the first cylinder return hoses. I think I do need to go back to the regular rubber ones to seal a bit better.

Anyway, was going to take it out until I saw that my turbo brace/stay was cracked and fell off. So now how to repair that…

https://i.imgur.com/BNCBvUKl.jpeg

JHZR2 09-09-2024 12:37 AM

I’ve put about 150 miles on it since I did the DVs.

My take is that the injectors are quieter, I can’t tell that there is as much knock.

I still get a rhythmic metallic tapping at a slower frequency. Maybe that’s the lift pump or something? I notice it’s most pronounced at hot idle and when driving in high gear at low rpm, 1100-1250 call it, where I hear it most pronounced.

gmog220d 09-09-2024 07:51 AM

Quote:

Originally Posted by JHZR2 (Post 4329202)
I still get a rhythmic metallic tapping at a slower frequency. Maybe that’s the lift pump or something? I notice it’s most pronounced at hot idle and when driving in high gear at low rpm, 1100-1250 call it, where I hear it most pronounced.

Vacuum pump?

JHZR2 09-09-2024 08:28 AM

Quote:

Originally Posted by gmog220d (Post 4329206)
Vacuum pump?

Not according to my mechanics stethoscope, but who knows at this point. It is the updated style, but I guess that may not mean much…

I drove it again today from cold. So the first cold and low speed drive since I had redone the DVs. In urban locations where there are structures on both sides to hear sound bouncing off, it sounds excactly the same as before. At idle it’s arguably quieter. But from just off idle to about 1500 it sounds like rocks in a box rattling around. After that it’s smooth and quiet.

It also seems smokier or smellier than before but that’s not necessarily true.

All injectors were redone by greazzer a few thousand miles ago, so I know they’re good, and all lifters are new INA.

ah-kay 09-09-2024 12:01 PM

Quote:

Originally Posted by JHZR2 (Post 4329133)
Replying again to let you know that I have taken your advice and did the DVs today.

Removing the intake is the biggest hassle. Not hard, just a hassle. DVs were easy. A mess, but easy. I used compressed air and cleaned as best as I could.

https://i.imgur.com/NZmlA0kl.jpeg

O-rings were hard as would expect.

https://i.imgur.com/ZTbUXksl.jpeg

And the old crush washers had a slight wear ring

https://i.imgur.com/wRUIOCZl.jpeg

https://i.imgur.com/bkdC2xUl.jpeg
https://i.imgur.com/9t2F67gl.jpeg

https://i.imgur.com/RmsW02Ml.jpeg

Torqued them as per the instructions.

https://i.imgur.com/ulkT4JGl.jpeg
https://i.imgur.com/J5bMV7zl.jpeg

https://i.imgur.com/SSlrMfQl.jpeg

It took some cranking to get the air out, but it worked out ok and fired up. It still has a knocking sound, and what I’m seeing is a lot of more frothy bubbles in the first cylinder return hoses. I think I do need to go back to the regular rubber ones to seal a bit better.

Anyway, was going to take it out until I saw that my turbo brace/stay was cracked and fell off. So now how to repair that…

https://i.imgur.com/BNCBvUKl.jpeg

I think you need to sit down and have a cup of coffee. All the sounds are perceived only.

JHZR2 09-09-2024 12:05 PM

Quote:

Originally Posted by ah-kay (Post 4329217)
I think you need to sit down and have a cup of coffee. You are confusing about your OM602 ( turbo bracket broken ) and OM603 ( DV replacement ).

Huh? No.

I have a lot of diesels as you can see from my signature. The knock that pushed me to work on lifters, injectors, and then DVs is for the 602 in my 91 300D 2.5.

I did have an issue of misfire/broken cam due to bad work from an MB shop, on one of my 1991 350SD cars. But that’s entirely separate.

Injector knock is only associated with my 1991 300D - the only cross between them is that the 603.97 and the 602.96 both use the same model injector in the angled design.

Edit - I see you edited (I had quoted your original which has changed). Perceived? It’s definitely noticable in terms of the difference between this 602, and my 601/603 engines. Let alone my 616/617.

ah-kay 09-09-2024 12:12 PM

Quote:

Originally Posted by JHZR2 (Post 4329218)
Huh? No.

I have a lot of diesels as you can see from my signature. The knock that pushed me to work on lifters, injectors, and then DVs is for the 602 in my 91 300D 2.5.

I did have an issue of misfire/broken cam due to bad work from an MB shop, on one of my 1991 350SD cars. But that’s entirely separate.

Injector knock is only associated with my 1991 300D - the only cross between them is that the 603.97 and the 602.96 both use the same model injector in the angled design.

Edit - I see you edited (I had quoted your original which has changed). Perceived? It’s definitely noticable in terms of the difference between this 602, and my 601/603 engines. Let alone my 616/617.

Good luck with the fixed. If I were you, I would push them off the cliff. Out of sight, out of mind.

JHZR2 09-09-2024 11:29 PM

Quote:

Originally Posted by ah-kay (Post 4329220)
Good luck with the fixed. If I were you, I would push them off the cliff. Out of sight, out of mind.

Huh??!? Why? If that’s the case why are we here? These are great driveable classics and a hobby for many of us. Getting some kinks out is part of the job.

My w123 cars are like new. My w126 with the broken cam was like new, it won’t take much to get it back - it’s already running great and the ax still holds charge The other w126 I’d drive across country tomorrow. The w201 is like new from original owner.

Perfect is the enemy of good enough, sure, but it doesn’t mean we shouldn’t stick to keep our cars close to new.

JHZR2 09-13-2024 07:11 AM

So, I can say that the injector sound is the same after replacing injectors and DVs. To be honest I can’t isolate the sound via stethoscope. I can isolate it via cracking fuel lines.

Definitely not a lifter either.

Any other thoughts?

Noticeable at idle. Louder and more obnoxious just off idle through 1200-ish RPM, then silent.

jdulle 09-13-2024 08:08 AM

Mine does something like this, it seems to make the most noise at 1,200rpm, and sounds fine over 1,800. Mine also vibrates a lot at idle, which my mechanic assured me was just the engine mounts. If you figure it out great, but I don't think it's going to stop the car from going thousands or hundreds of thousands of more miles. Are you getting good power and economy?

jdulle 09-13-2024 08:10 AM

I do think these engines make more noise/vibration at low rpm compared to om 602 or 606. All of the 602's I have seen are like this and 606 are smoother. But the 606 gets 33mpg, and the 602 is capable of 47mpg (I was surprised, but managed this on a 200mile trip recently).

JHZR2 09-13-2024 09:03 AM

Quote:

Originally Posted by jdulle (Post 4329796)
Mine does something like this, it seems to make the most noise at 1,200rpm, and sounds fine over 1,800. Mine also vibrates a lot at idle, which my mechanic assured me was just the engine mounts. If you figure it out great, but I don't think it's going to stop the car from going thousands or hundreds of thousands of more miles. Are you getting good power and economy?

Car runs absolutely beautiful, sounds fine, and is smooth.

5 cyl engines are less balanced than 6cyl, so there’s that. But a good running one is no issue at all.

To get 47 MPG you must have been driving 35-45 mph with no stops and no AC.

rrgrassi 09-13-2024 05:46 PM

When I had my '91, cylinder #2 had a nailing injector. Swapping injectors did nothing. Turned out, in the IP, the delivery valve was almost a 1/4 inch too high, causing over fueling. I bought a used injector pump, but never got to install it.

jdulle 09-13-2024 06:07 PM

I was going 55-63 most of the time. I couldn't believe it either, but I filled it up until I could see fuel in the filler neck both times and it used 3.1 gallons to go 142 miles. I had to check the distance on google because the odometer doesn't work. It was almost as good as the manual transmission TDI I have.


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