Loud motor knocking/clacking, No power

[Willys]

lol.....yep, a good slide hammer wins again!

Those injectors look dirty....lol. Soak them well in strong carb cleaner, not the green version. Then take a spray can of strong carb cleaner and blast down the inlet tube to clean out the innerds....you could also take the nozzles off each injector and carefully using a soft bristled brush NOT and type of wire!!!! Sacrifice many old tooth brushes or find a stiff natural type brush like the bambo ones for a BBQ again not anything made of metal/wire. The wire brushes will deform the openings of the nozzle and you'll be buying new nozzles if you can find them? They must be identical to what you have in there now.
Once you do get the nozzles out you can now flush them using carb cleaner again. You are looking for 5 strong streams of fluid coming from the end. 4 going equally spaced apart and a single spraying off on it's own path, it's directed at the glow plug. You can mark scratch the body of the injector and side of body of nozzle before taking them apart to make sure you replace the nozzle in the right configuration. Just do not touch the end of the nozzles. The end cap for the nozzles are TIGHT! But they do release with pressure. Do not use the top hexhead to hold the injector as it's very weak and it'll break trying to undo nozzle caps. You must clamp body near the top of the injector body in a strong vice to be able to break those caps free, imho.  Also do not use a thin piece of wire to try and clean out nozzle holes, you'll only (F) them up. You only used forced cleaner through the nozzle to clean them as best you can after a good soaking. Some folks say you can use oven cleaner...? I always use the strongest carb cleaner and plenty of it.  The best way is a sonic cleaner.
When you get the nozzles out you will find a needle inside the nozzle. Look at the sharp end and see if it is badly scorned, it'll have deep groove worn into it from constant beating open and closed. IF really deformed think about new nozzles. The used to be around $60 each about 5 years ago. I do not remember if it was amazon or ebay where I was finding them, but the numbers and even the plus marks must be the same or you won't get the correct fuel delivered through the injectors. 

I'm sure there are many threads researching injectors on this site.

Good luck.

[LooseLugNuts]

On 7/6/2025 at 1:31 PM, Toxophilite said:

oh heck, no welding facilities, no old glow plugs

 

 

you have 3 old ones in your engine that you should (very carefully) replace with 3 new ones; )

 

 

and its a good idea to ream out the glow plug bores while youre in there...i remember welding a long bolt to a drill bit to get that job done...i dont remember what sized bit i used but i do remember coating it in grease first to minimize the amoiunt of carbon that inevitably falls into the combustion chamber

[Toxophilite]

I'm soaking the injector ends in carb cleaner right now and giving them some toothbrush love.

 

When you clamp them to get the 'caps' off do you do it at the `12mm waist/slot?. I was trying a 12mm on the waist and a 155 on the cap and it does NOT want to move.

 

Also should these injectors have rudder O rings in the round groove?

I also read about copper washers...but where? Still in the hole the inectors came out of? Fish them out with a bit of wire or appropriate tool?

Edited July 23, 2025 by Toxophilite

[Toxophilite]

used some flattened round aluminium bar to clamp the injectors in the vise...of course I forgot to mark them prior..ah well.

After some time soaking the business end I carefully took them apart, 2 have nice 5 spray patterns one produces 2. It gets more soaking

 

I found the copper washers..or at least 2 of them, in their holes where they belong. When I was removing the one injector a big chunk of crud fell in the hole..I could see it so I had the brilliant idea of shop vac-ing it out....So I probably shop vac-ed that washer up as it is gone. I looked in the vacuum and sifted through the debris, no luck.

I'm betting it was still in the hose and maybe ended up on the ground somewhere as I walked the shop vac back around the house..yay!

 

So if someone knows a trusted not too expensive source for new ones that would be dandy thanks.

 

Edited July 24, 2025 by Toxophilite

[Willys]

As LLNS suggests, look on amazon and find the injector seat cutting kit, $39 ish I think it was.....far easier than welding a drill bit and getting the seat angle wrong. It'll leak.  The kit comes with 5 or so different angled cutting tools. Works extremely well.  As for the copper washers, that's a dealership trip and when there buy two sets, they are relatively cheap or at least they used to be.

[Toxophilite]

THanks! Just to clarify. Loose lug nuts was talking about  boring the glow plug holes not re cutting the injector seats. I will contact the local Mercedes dealership vin in hand. In general I haven't found them useful for parts.(edit) they have them $6 each tiny copper washer..might just buy the one!

 

Are the injectors supposed to have rubber O rings around them right above the nozzle cap?

Edited July 25, 2025 by Toxophilite

[Toxophilite]

only 21.35 for the three washers!!  I’m pretty disappointed that they aren’t embossed with the mercedes logo though. I paid them mostly in quarters, dimes and nickels bahahahaha. my one problem nozzle has only 3 jets when tested. Has seen soaking in carb cleaner for a couple days,. under a magnifying lens it's still kind of dirty. I do have access to an ultrasonic cleaner if I drive across town. So I can use steel wool or anything stronger than a toothbrush on the injectors nozzles?

[Willys]

No rubber O ring in the caps or above the caps for the nozzles. Sorry thought LLNs was refering to the injector seats, I did the same thing for my glow plug holes, greased up drill bit and your shop vac....
So they have gone up some since I bought my set....lol....not by much though!! They used to be dirt cheap!  I used to go in and buy all they had, seeing I was taking my injectors in and out so frequently.
NO WIRE ANYTHING anywhere near the tip of the nozzles, UNLESS you want to buy new nozzles....!!!!!

I would try and find nozzles before trying using anything but chemical cleaning. I have a 6 quart sonic cleaner and I can submerge the entire injector.   Also, be very careful not to mix up the parts between your injectors....easily done if you get carried away.  Nothing beats the results you can get from sonic cleaning, even multiple baths in very hot fluids. 
About sonic cleaners, you can just put your dirty parts in a tuperware container in strong carb cleaner, floating inside just clean water. It helps stop the contamination of the whole cleaner unit and wasting expensive cleaner so quickly. Youtube trick and it works! Research it if you want.

Under very strong magnifiers you can see the deformation of the orfises(?) from the high pressure fuel being sprayed out of them. That is after they are clean.

[Toxophilite]

If I can get a friend to sonic clean my injectors. Should I just do the nozzles and accompanying nozzle bits?

Or should I be removing the electrics and trying to do the whole shebang? I was thinking of picking up a new nozzle just in case. I sonic cleaning sometimes ineffective in cleaning clogged nozzles?

Edited July 26, 2025 by Toxophilite

[Toxophilite]

Before I drive across town. what about heat? Could I heat up the nozzle tip? Not hot enough to lose temper etc. if it has any, but enough and then a dip , slosh around in  carb cleaner and spray through

[Willys]

I hang the top out of the sonic cleaner and do the entire injector, then take nozzles out and do them separately as many times as it takes to get them as clean as I want them.  You are really after that spray pattern as best you can get it.....many baths and then slap nozzles on injector and spray carb clean through to see if you gat the 5 spray pattern.
I have never tried heat as I expect the nozzles to be tempered and the needle looks like it has a coating on it? The needle must seat correctly inside the nozzle or you will get poor spray and complete shut off of fuel....no...???
The trick is to make sure you have one injector untouched while doing the other two, so when you forget how all the shaft and spacers, washer etc go in sequence, you have something to go back to.  Sorry should have said this at first....lol.

The injectors live in a hot environment when engine is running so not sure if you can loosen the crud that way...?????  Be interesting to see if you do try and it works without ruining the nozzle...?

[Toxophilite]

Yes I have had the nozzles off, the needle, the locating pins, the little push bit, the spring, the washer etc. I think I have the order right. I'll be doing this at my friends place of work so I don't know how long I can run them through as I will have to kick my heels across town while he does it. I guess it might be worth buying my own unit. Any recommendations? Looking on amazon is a but baffling. If you're hanging the injectors you have something probably 8" deep? I was blowing wd 40 through the nozzle to see the pattern. As I said 2 seem pretty good, but I'd clean them further anyway, it's just the one that just has 3 jets clear

[Toxophilite]

Looking at this unit. (no affiliation) maybe 2 or 3 litre (supposedly none are the advertised size)

https://www.vevor.ca/ultrasonic-cleaner-c_11064/digital-2-l-ultrasonic-cleaner-with-brackret-timer-bracket-jewelry-p_010447073412?adp=gmc&utm_source=google&utm_medium=cpc&utm_id=20173896858&ad_group=&ad_id=&utm_term=&gad_source=1&gad_campaignid=20178693536&gbraid=0AAAAACYN8u7fODCUBrFtxjp1zNXe_2AVp&gclid=Cj0KCQjwnJfEBhCzARIsAIMtfKJkRC-rIhFpISvU8Hx7O9TaseS9_8vp2RWBqDgmv6dih_TcCHm6NX8aAoyEEALw_wcB

 

Looks like you could fry up some chips in it too!

Edited July 28, 2025 by Toxophilite

[Toxophilite]

Friend's ultrasonic unit across town did the trick . final try was with pine sol, 5 nice clean sprays from the plugged nozzle.

ThE other nozzles just got the initial few cleans despite having 5 good jets. Better to have it as clean as possible

 

I was reassembling but realized I might need some high heat silicon/ceramic grease. I've read that normal grease when it's at high temperature basically glues the injector in again. Is this the case?

 

[Willys]

Soak everything in diesel as you assemble the injectors. I made the mistake on a set and forgot about them and assembled them perfectly clean and dry, 3 months later they were rusted solid!!!! RUINED!!!!
I now soak them in diesel and they stay perfectly fresh!
My sonic cleaner was $200 many years ago before they got cheaper in price. It's a 6 litre model and 6" deep I think, rectangular in shape.

[Toxophilite]

I mostly did that, was pouring diesel into the injectors and dipping bits into diesel as I assembled them . Then I reinstalled them witht he cermaic grease and new crush washers to the specified torques. hooked everything up properly, primed the fuel system as suggested by Evilution. Turns over but no firing. Tried cracking the nuts on the lines to the injectors to let any air out, got a little bubbling from one. Still no firing/starting  though. Tempted to take the injectors back bout, hooked them up and see what they're doing outside the car(into a bucket/box)

 

I hooked up the code reader a friend lent me ( when the %$#&%^ amazon one didn't work) and I got PO193 Fuel Rail pressure high input

DTC severity 2 out of three.

I got this same reading just prior to pulling the injectors and doing the injector work. 

I guess i'll start looking at the sensor then try and check the filter, fuel pump etc.

Edited July 31, 2025 by Toxophilite

[Willys]

Have you checked all the wiring to the injectors? Sorry too lazy to re-read all our posts...lol.  I have a lot of house repairs on my plate at the moment. Sorry. 
I have heard that someone had a bad connection at the top of the injector...? 
Do you have a membership to Evilution? Well worth the price of admission imho........days of information in their library......I haven't been their in years so can't say what it's like today...?

 

[Toxophilite]

YEs I do have a membership and I agree. It's a great site. I will go there and reseacrh

Edited July 31, 2025 by Toxophilite

[Toxophilite]

Now I'm wondering about my reassembly of the injectors. I have all the parts in the right order(I just did the nozzles actually and soaked the upper half but not the tops)

When I reinserted the needle into the nozzle it basically went all the way in and sat flush on top, is that right? Is it supposed to sit a little proud and I basically plugged them?

[Toxophilite]

Managed to get the smart started however it's exhibiting the exact same symptoms as before clackita clackita, lots of unburnt fuel, sounds like a cylinder or two isn't firing.

Maybe it's time to push it off a cliff?

[LooseLugNuts]

1 hour ago, Toxophilite said:

Managed to get the smart started however it's exhibiting the exact same symptoms as before clackita clackita, lots of unburnt fuel, sounds like a cylinder or two isn't firing.

Maybe it's time to push it off a cliff?

 

 

no///////////

 

just imagine the joy and elation when you finally get it running good

 

it will be 1000 times more magnificent and satisfying than a 3second cliff jump

 

[Toxophilite]

27 minutes ago, LooseLugNuts said:

 

 

no///////////

 

just imagine the joy and elation when you finally get it running good

 

it will be 1000 times more magnificent and satisfying than a 3second cliff jump

 

Far from any convenient cliffs with a non-running smart! Might try pulling the injectors and see if I can rig it up to see if they're all firing outside the engine

[Toxophilite]

Pulled the injectors, or course no way to hook them up in situ out of the motor.

 

#3 injector (or the one closest to the belts and pulleys) had a very dark wet nozzle while the others looked pretty well normal

There's a guy a couple hours away that's selling supposedly tested used injectors for $75 a pop

I have bought smart bits off him before. However I don't really know if that's my problem. Might be good money after bad.

Tried to get a resistance reading off the injectors, seemed to be .6 - 1.5 ohms depending on when I took the reading. Didn't make much sense actually. I have a good meter and make my own tube guitar amps so I know how to use one. Anyway to test to see if the upper half is actually working?

 

[Willys]

13 hours ago, Toxophilite said:

Now I'm wondering about my reassembly of the injectors. I have all the parts in the right order(I just did the nozzles actually and soaked the upper half but not the tops)

When I reinserted the needle into the nozzle it basically went all the way in and sat flush on top, is that right? Is it supposed to sit a little proud and I basically plugged them?

Yes they sit flush, and the needle should slide into the nozzle easily.
I hate electronics and can't figure it out without a nose bleed...lol....so I phone a friend when it comes to the white smoke....lol.
Have you tried Izzy, Stickman007. He is a wizard in the white smoke section....and a great guy to deal with. He's just north west of Edmonton also. Electronics is his specialty.

[Toxophilite]

ahh you mean the contained magic smoke that makes all electronics work.