Loud Tapping, Rough Idle, Had to Tow - Page 5 - PeachParts Mercedes-Benz Forum

TnBob · #61 05-19-2015, 06:09 PM

OR ... swap the #2 injector with any of the others... see if the issue follows the injector or stays with cyl 2

DeliveryValve · #62 05-19-2015, 06:40 PM

^^^ let's hope it's that easy.

Maxbumpo · #63 05-20-2015, 12:35 PM

Quote:

Originally Posted by TnBob

OR ... swap the #2 injector with any of the others... see if the issue follows the injector or stays with cyl 2

Don't forget a new heat shield under each injector -they are one time use. I would hold off installing them for this simple test - re-use the old temporarily, but don't forget to install new before you drive the car again.

And if after the swap the noise is still at #2, then swap the DV/holder assembly for #2 with another. Keep each DV/holder together as a set, replace the O-ring and copper crush washer with each. You can cheap out and not replace the O-ring, the worst consequence is a small leak, but you really need to replace the copper crush washer. If you have a propane torch, you can hang the copper washer on a piece of wire and heat until glowing orange. Let it cool in the air, then clean clean clean to get all the oxidation off. This will re-soften the copper so that it will be able to form a seal again. Once bright and shiny, re-use. I've done this many times on copper seal rings for hydraulic systems when I'm caught out with no new washer, never had a leak.

kalikar85 · #64 05-20-2015, 03:07 PM

Thanks, im swapping them today. Had to track down new hose
For the record its braided 3.2mm I.D. X 1.9mm. And its a little difficult to find metric hose.
I also have a 27mm deep socket and breaker bar to remove the injectors but the socket doesnt fit all the way down. It only goes to the 22mm part halfway doen the injector before the nipples hit the inside of the socket.
Do you need an extra deep socket?

Maxbumpo · #65 05-20-2015, 04:15 PM

Quote:

Originally Posted by kalikar85

Do you need an extra deep socket?

You need one that has thin walls almost all the way up.

Sears used to sell a socket that worked, that's where I bought mine years ago. Is there a Harbor Freight near you? May try their socket to see if it works.

kalikar85 · #66 05-20-2015, 04:47 PM

Quote:

Originally Posted by Maxbumpo

You need one that has thin walls almost all the way up.

Sears used to sell a socket that worked, that's where I bought mine years ago. Is there a Harbor Freight near you? May try their socket to see if it works.

Thanks, it turns out the nipples may sometimes have to be bent in a very tiny amount (less than 1mm) for a standard 27mm deep socket to fit all the way down.

----

Swapping the #1 and #2 injectors did not make a difference. (#2 spot still did not make a difference with #1 injector in its spot and connected/disconnected.) same with the #5 injector in #2 spot.

Looking beneath the injectors, they all have a greenish patina fuzz on the parts inside and #2 is just dry iron. The difference is shown in the photos. This makes it pretty clear that #2 is not firing, that this is at least part of the knock/tap, and is not the result of a damaged or clogged injector.

Quote:

Originally Posted by DeliveryValve

Have you used a stethoscope to locate the sound?

An ear to a breaker bar probed around the valve cover did not determine anything. Im not sure what Im hearing. The tap/knock appears to be due to the #2 misfire.

Quote:

Originally Posted by DeliveryValve

Since #2 made no difference, it's dead. I suggest to investigate further and get a compression reading. You most likely have no compression on that cylinder, either valve related or piston related.

Looks like a re-check of the valves and a compression test is in order. Going to rent one from a local shop.
looking at this thread for procedure and readings ("above 350"): 300D Compression test

TnBob · #67 05-21-2015, 01:20 AM

Question based on your last post.
When you bleed the injectors, were you getting fuel coming out the
injector feed line to the #2 injector ?

Maxbumpo · #68 05-21-2015, 10:49 AM

Quote:

Originally Posted by kalikar85

Swapping the #1 and #2 injectors did not make a difference. (#2 spot still did not make a difference with #1 injector in its spot and connected/disconnected.) same with the #5 injector in #2 spot.

Looking beneath the injectors, they all have a greenish patina fuzz on the parts inside and #2 is just dry iron. The difference is shown in the photos. This makes it pretty clear that #2 is not firing, that this is at least part of the knock/tap, and is not the result of a damaged or clogged injector.

Excellent, now you are getting somewhere!

Not firing may be due to low compression (rings, valves, other major internal failure) or may be due to a lack of fuel to the injector or fuel getting there too late or too early.

I am a big fan of troubleshooting in the order of simple/cheap and progressing to expensive/complex. Valve adjustments, Compression check and swapping injectors or delivery valves is cheap and relatively simple if you have the right tools.

I would look at (1) is there any fuel getting to the injector at all, and if yes then (2) swapping delivery valves around in the same manner that you just did with the injectors.

kalikar85 · #69 05-21-2015, 02:47 PM

Quote:

Originally Posted by TnBob

....When you bleed the injectors, were you getting fuel coming out the
injector feed line to the #2 injector ?

Quote:

Originally Posted by Maxbumpo

Excellent, now you are getting somewhere!

....may be due to a lack of fuel to the injector or fuel getting there too late or too early.

I am a big fan of troubleshooting in the order of simple/cheap and progressing to expensive/complex. Valve adjustments, Compression check and swapping injectors or delivery valves is cheap and relatively simple...

I would look at (1) is there any fuel getting to the injector at all, and if yes then (2) swapping delivery valves around in the same manner that you just did with the injectors.

Wow, thank you.

Compression test in progress. Harbor Freight $33 Kit. +1

Fuel hard lines removed, all injectors removed, gauge in injector place with washers and heat shield, glow plug relay unplugged (so engine doesnt start), and turning over by jumping starter by relay near battery, turning over 5-10 times until gauge doesnt increase.

The psi was less and less each cylinder tested as the battery drained. When checked again the reading was less on same cylinder the second time.

In order:
#3: 340psi
#4: 340psi
#5: 280 psi
#1: 245 psi
#3 (again): 245psi

Am I performing this test correctly? Ive never done engine work before aside from valve adjustment which had very detailed instructions.
Battery is slow charging to try the compression again on a hot engine.

With the hard lines removed behavior of the Delivery Valves doesnt match.
Delivery Valves #1 and #2 are dripping not shooting. #3, #4, #5, all shoot fuel.
can be seen here:https://youtu.be/scpHcSosM4I (the spray blurring in front of the camera is from the disconnected braided line that goes to injector 1)

Maxbumpo · #70 05-21-2015, 03:48 PM

Did you test compression for #2 hole?

kalikar85 · #71 05-21-2015, 04:31 PM

Quote:

Originally Posted by Maxbumpo

Did you test compression for #2 hole?

Charged battery for 2 hr, ran engine until warm, white smoke from exhaust:
#2: 290 psi
#1: 350 psi
Battery drained
¯\(°_o)/¯

Maxbumpo · #72 05-22-2015, 09:22 AM

Possible sources of your issue: injection pump (including delivery valve), rings, valves.

You could try a leak-down test to determine if #2 cylinder is leaking out the intake valve, exhaust valve, or rings.

funola · #73 05-22-2015, 09:43 AM

290 psi should be enough to ignite injected diesel with good spray pattern. Your youtube on delivery valves cranking clearly shows differences in their outputs. Problem in likely in some of the delivery valves or the IP itself. I'd rig up one injector + 1 hardline line (may have to bend it) to spray in the air and watch while cranking, one delivery valve at a time.

Does the white smoke smell like coolant? You mentioned blowing coolant out the expansion tank before which is not good.

Maxbumpo · #74 05-22-2015, 10:49 AM

Quote:

Originally Posted by funola

Problem in likely in some of the delivery valves or the IP itself. I'd rig up one injector + 1 hardline line (may have to bend it) to spray in the air and watch while cranking, one delivery valve at a time.

I like that idea!

kalikar85 · #75 05-22-2015, 04:10 PM

Quote:

Originally Posted by Maxbumpo

Possible sources of your issue: injection pump (including delivery valve), rings, valves.

You could try a leak-down test to determine if #2 cylinder is leaking out the intake valve, exhaust valve, or rings.

Any threads or tutorials on a leak-down test?

Quote:

Originally Posted by funola

290 psi should be enough to ignite injected diesel with good spray pattern. Your youtube on delivery valves cranking clearly shows differences in their outputs. Problem in likely in some of the delivery valves or the IP itself. I'd rig up one injector + 1 hardline line (may have to bend it) to spray in the air and watch while cranking, one delivery valve at a time.

Does the white smoke smell like coolant? You mentioned blowing coolant out the expansion tank before which is not good.

new nss. *if you read back the oil overfill, incorrect dipstick reading, and nss were the initial problems before dead cylinder reared its head. started with key fine for about 2 hrs. then after testing each injector cranking off the hrdlines the key wont start it again!

did diesel purge and new intake filter
checked cam lobes #2 i and e are right on spec. .012 .004
ran with valve cover off. all cam lobes are pushing the rockers and valves.
adjusted the rack damper which make the misfire more pronounced when loosened out so i put it back where it was.
rechecked compression very carefully engine hot, all injectors out, on #2. still at 290 psi.

hooked up one injector and hardline to feed off of each delivery valve.
not getting any visible spray into air while cranking.
they dont spray right off the hard line. do you need the braided line attached?
should all delivery valves be shooting up with the hardlines removed? 1,2 and 3 alternate between a strong stream and a dribble. 4 and 5 both shoot a fountain stream straight up a few feet into the air.

the white smoke is gone (i think it was just normal white start up smoke which i get on a new full tank or purge) but the exhaust smells sooty. hadnt noticed before but there is a spot of black soot on the ground under the exhaust pipe. the exhaust smells almost like carbon monoxide. not the clean diesel smell.

im totally stumped here. i would suspect a head gasket but the compression is good. Maxbumpo had mentioned that the oil overfill could have caused oil lapping at the rear main crank seal where it was leaking. could this be affecting the nss or something connected with starting?could a rod bearing knock on piston 3,4, or 5 cause a dead #2 cylinder and its vibration cause repeat nss failure?

if anyone knows whats going on with this thing please chime in. im way in over myhead

still have knock and shake, dead #2 cylinder & repeat nss failure.
id rather not walk away from this thing but its been 2 weeks doing the wrench dance in vain thanks