Shaking engine, misfires and a lot of smoke after 40 seconds at a cold start - PeachParts Mercedes-Benz Forum

Mimo · #1 01-24-2012, 01:44 PM

Hello guys,

I'm Mimo and have a W201 190 2.5D.
I have a problem with the engine after cold starts. 40 seconds after a cold start, the engine (OM602) starts to shake and at the same time you can hear a loud knocking coming out from the engine. Also at the same time ther is more smoke then normal.
It looks like that after 40 seconds the engine is running on 3 or 4 cylinders instead of 5.
I made a video to show you what i mean

Schudden en roken bij koude motor - YouTube

below a list of things that I have already done to solve this problem but unfortunately without results

.

The injector nozzles are replaced en tested by a Bosch service centre.
A have done a motorflush and replaced the oil (5W30) and all the filters.
I have replaced the return hoses at the injectors
I have checked the chainstretch and adjusted the pumptiming

Can anyone tell me what to do next?

Thanks.

vstech · #2 01-24-2012, 03:14 PM

Welcome Mimo!

have you gotten a compression reading on all your cylinders?

5w 30 oil is too thin unless you are below -30C temps... are you sure the oil is diesel rated? it's doubtful the problems are due to the oil, but still should know for sure.

how many kilometers on the car?

sixto · #3 01-24-2012, 03:22 PM

Glow plugs? Should clear within a few seconds if that's the only problem.

Sixto
87 300D

Mimo · #4 01-24-2012, 04:08 PM

Thanx vstech!

I haven't got a compression reading yet. I hope to do it this week.
I did a motorflush 2 months ago because a mechanic told me that it could be a sticky valve tapet. After the motorflush I had to use thinner oil to see if this was the problem. This oil is diesel rated. The car has 280.000 kilometer on te odometer.
The engine starts immediatly when I turn the key en than runs nice for 40 seconds. After that the knocking, shaking and smoking begins and stay like that until the the engine reaches a temperature of 80ºC

kerry · #5 01-24-2012, 04:18 PM

I think there's a problem with one or two cylinders, probably low compression. The afterglow feature on the glow plug relay is keeping those cylinders firing until it cuts out. Then those cylinders won't fire until the whole block is heated up. Stuck rings maybe.

vstech · #6 01-24-2012, 04:26 PM

can you break the injector line nuts while the motor is skipping and see if you can isolate some dead cylinders?

Mimo · #7 01-25-2012, 09:10 AM

Today I did break the injector line nuts and i could see that there was no change at the 3rd cylinder. I assume that this is the dead cylinder.
I also have tested the afterglow. After a few seconds (30 or 35 seconds) when the afterglow has stopped the problems started.
I heard from a mechanic that if the rings are stuck that there will be pressure in the valve cover. When I open the oil cap there is no pressure.
Today I will call a mechanic for a compression and leak down test.

Mimo · #8 01-26-2012, 02:35 PM

Tuesday I have an appointment for a compression test and a leak down test.
I was trying for more than 6 months to find out what the problem was and I hope to find out tuesday.
Can someone tell me what is causing the compression problem? Is it the valves, the headgasket, stuck rings or even a bended connecting rod
Thank you all for so far

vstech · #9 01-26-2012, 03:04 PM

Swap #3 & #4 injectors see if #3 is still dead

DieselPaul · #10 01-26-2012, 03:07 PM

If you rev it does the cylinder come back? Could be delivery valve seals, my car misfired at low RPM but ran fine off idle.

Mimo · #11 01-26-2012, 05:12 PM

I will try to swap the injectors this weekend to see if the 3rd cylinder stays dead and yes when I rev it, the cylinder seems like to come back.

Mimo · #12 01-27-2012, 12:37 PM

Dieselpaul, What do you mean with a delivery valve? Do you mean the whole set or can I just swap the spring, the copper ring and the O-ring?
Today I did break the injector line nuts to see if all lines spray the same amount of diesel. When I finished, I saw diesel bubbling at the 3rd injector.

Mimo · #13 02-02-2012, 03:48 PM

Yesterday I did a compression test. cyl.1 25 bar, cyl.1 25 bar, cyl.1 24 bar, cyl.1 30 bar, cyl.1 23 bar.
The have also set the IP a little bit earlier (before it was 14º ATC).

Mimo · #14 02-04-2012, 04:20 AM

The engine now runs much better. After the afterglow the engin is still shaking and smoking but after 500 meter the shaking is gone and also the smoking even when the temp is below 40ºC. This is an improvement but the engineer told me he is 100% sure that I have a bent rod.

Cherry300d · #15 12-01-2013, 12:07 AM

My name is Stefano and I'm new at pelican parts forum.
So long story short... I did a tune up on my 300d 5 months ago; valve adjustment, motor mounts, diesel filters, oil change, and injector nozzles.... It was my first time ever doing nozzles and guided myself thru the internet to rebuild them myself. I got around them but shortly the leaked by the body and had to do it over and over again couple of times till finally stopped. I felt sketchy taking them apart over and over again trying to to clean them and make them stop leaking by. I used bosh nozzles and really wished I could've bought new ones instead if I knew.
Two days ago my car started to do a weird misfire on every start where it bairly wants to start and smokes lots of blue smokes. Once I finally crank over and over it starts and it runs fine. I know for a fact it's not my glow plugs. They work. A day ago the engine was locked as if a had water inside a cylinder and I tried cranking and it locked and finally and started and all this crude diesel smell and tons of smoke came out the car. Once again it ran fine after .... I'll try posting a video . Help from anyone would be appreciated .. Thanks