Update: replaced the two 5/16" fuel lines and the in-line angled filter. Immediate different in starts. Fires up like a charm now. Old filter was filled with black particles. Knock remains.

Going to get some of that fuel return line next.

Good work!

I strongly recommend the Tygon stuff. I bought the stuff from Auto Haus AZ for years and I kept replacing it every 4-6 months. I've had that yellow Tygon stuff in for a year+ now. No issues.

__________________
Cruise Control not working? Send me PM or email (jamesdean59@gmail.com). I might be able to help out.
Check here for compatibility, diagnostics, and availability!

(4/11/2020: Hi Everyone! I am still taking orders and replying to emails/PMs/etc, I appreciate your patience in these crazy times. Stay safe and healthy!)


82 300SD 145k
89 420SEL 210k
89 560SEL 118k
90 300SE 262k RIP 5/25/2010
90 560SEL 154k
91 300D 2.5 Turbo. 241k
93 190E 3.0 235k
93 300E 195k

Cool cool. Thanks for the recommendation. I'll try and order some.

I like that it doesn't harden up. I like clear fuel line on small 2 stroke engines, but it hardens up real quick and you have to replace it a lot.

So I just did a couple things.

First, I just let the car run for about 15 minutes to listen if there was a difference in the knock. Both my brother and I could both tell that the knock became less pronounced as the engine warmed. However, I wouldn't say at all that the knock went away. You could definitely still hear it.

Then, I did the diesel purge thing using Seafoam. Not sure how the products compare exactly. But it didn't seem to make much of a difference. Maybe a little. Got some black colored fluid and am going to change the fuel filters. But the Seafoam definitely didn't remove the knock. Also, cut the ends of the fuel return lines and reattached. Cant tell how much of a difference that made since there's already a lot of fuel leaked at the injectors. Any other thoughts?

aaaaaaand now another update.

decided to take it for a spin and run it pretty hard. got it up over 40 under load, up hills, etc. and it made a huge difference. after that ride and listening to it idle in my driveway, there were times I couldn't hear any knock at all. when fully warm, it's probably 95% gone. which is a huge relief.

So, I guess the only question I have is, can I definitely rule out it's nothing to do with something deep in the engine? Before I start putting money into plugs, injectors, etc I just want to confirm this. 'Cause I don't have to tools/space to tackle an engine build, so I'd have to sell the car if that's the case and wouldn't want to have lots of money in it.

the 1/8" ID Tygon line can be had at Lawn Mower Shops.

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84 300D, 82 Volvo 244Gl Diesel

When you can find the new Turbo Diesel Pistons are like $360+ each.
Als the Exhaust Valves on the Turbo Diesel are rather expensive.

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84 300D, 82 Volvo 244Gl Diesel

That knock is nothing more than fuel knock from a sloppy injector. Time to have them re-tipped and the pop pressure set to specs.

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'83 300D, 126K miles.

I know the yellow tygon tubing you are talking about. It is Polyurethane, not PVC, very soft (too soft IMO) and you won't have any problems till there is some pressure build up in the lines due to restrictions somewhere and then one will pop off, spilling lot's of fuel. Just the nature of that tubing- too soft with no braiding like the OE hose. I expect you will have problems down the road.

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85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

I wonder why McMaster listed it as PVC. I'll keep an eye on it but I haven't seen any problems since I installed it about a year ago.

Here's the datasheet from Saint-Gobain / Tygon,

http://www.processsystems.saint-gobain.com/uploadedFiles/SGPPL-PS/Documents/Flexible_Tubing/FT-Tygon-F4040A.pdf

__________________
Cruise Control not working? Send me PM or email (jamesdean59@gmail.com). I might be able to help out.
Check here for compatibility, diagnostics, and availability!

(4/11/2020: Hi Everyone! I am still taking orders and replying to emails/PMs/etc, I appreciate your patience in these crazy times. Stay safe and healthy!)


82 300SD 145k
89 420SEL 210k
89 560SEL 118k
90 300SE 262k RIP 5/25/2010
90 560SEL 154k
91 300D 2.5 Turbo. 241k
93 190E 3.0 235k
93 300E 195k

I hear the rapping sound at idle. I'd suggest ruling out external mechanical noise by removing all belts and run it for 15 seconds and see if the noise remains or goes away. Have you done a valve adjustment? If not, do it. Fix all the external leaks before doing anything else. The fact that you have black stuff in the primary fuel filter and replacing it makes the engine start and run better says you have an algae problem. Replace your secondary fuel filter also and buy some Startron for diesel fuel algae killer and follow the instructions.

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85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

Link does not say what it's made of. Max working temp of 165F is too low for comfort. Notice it only has vacuum ratings and not pressure? It probably won't even hold 2 psi at 195F.

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85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

Cool. I'm feeling more confident that this is the issue.

I just cracked each injector with the car running and the knock disappeared when I cracked injector 1 about a quarter turn. Tested all 5, and the other 4 still had knocking. Audibly, it's sounds like it's coming from 1 too.

Does this rule out any other knock, like a rod or piston slap? Hypothetically if one of those were the case the noise would still continue with a cracked line right?

From what I have read there is at least 4 of our Members using the Tygon Tubing for a few Years with no issue.

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84 300D, 82 Volvo 244Gl Diesel

No, you have identified the problem Cylinder.

To see if it is the Injector you need to move/swap the #1 Injector to another Cylinder and re-test those 2 Injector you swapped.
If the the problem follows the #1 Injector to the new cylinder then it is and Injector problem.

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84 300D, 82 Volvo 244Gl Diesel