OM603NA white smoke and very low power - PeachParts Mercedes-Benz Forum

giyom · #1 04-30-2023, 12:14 AM

Hi!

I am getting some noxious white smoke out of my OM603NA along with very low power. This is on a car I imported last year and which is supposed to be in good working condition but I haven’t been able to drive it so far given the low power and white fumes at idle and especially when accelerating.

Here are some videos of the engine and exhaust at idle:

https://youtube.com/shorts/plGkx0aEa3c?feature=share

https://youtube.com/shorts/a_2XvYriLac?feature=share

I have replaced the injectors and done several diesel purges with a separate tank. No change at all.

Next on my list
- compression test
- timing check

The only thing that changed since I got this car is that it is now at 7000ft (2100m) so I wonder if this somehow could explain the behavior. Maybe something wrong with the ADA?

Thank you I’m advance for any idea or advice. Cheers

JHZR2 · #2 04-30-2023, 09:49 AM

NA at elevation may have reduced power. But not enough to really matter in routine use, and not the cause of white smoke.

Have you ever gotten the engine up to temperature?

Does the radiator hose get hard very soon after startup, and before it should/the engine gets warmed up?

A slight bit of white smoke at cold start could be unburned fuel from low compression or bad glow plugs (does the glow plug light come on and do they actually work?).

White smoke can also be from water. And that’s the concern. Especially in a 603 engine. They have weak heads and are prone to head gasket failures due to the mixed metal construction of the block and head.

giyom · #3 04-30-2023, 04:32 PM

Quote:

Have you ever gotten the engine up to temperature?

I don’t know but my assumption is that running it idle for 30/60 minutes should get it to temperature and I did that with no change to the smoke

Quote:

Does the radiator hose get hard very soon after startup, and before it should/the engine gets warmed up?

It does not. I just ran it for 5 minutes and it stays soft like before startup.

Quote:

does the glow plug light come on and do they actually work?).

The glow plug light comes up and turns off. I then crank and the engine starts with no problem.

Quote:

White smoke can also be from water.

Yes but I’m this case it smells more like unburnt diesel so my assumption is that if it was a cracked head and the coolant was getting in combustion chamber the smell would be different.

Thank you again for all your advice and ideas!

JHZR2 · #4 04-30-2023, 05:07 PM

Quote:

Originally Posted by giyom

I don’t know but my assumption is that running it idle for 30/60 minutes should get it to temperature and I did that with no change to the smoke

It does not. I just ran it for 5 minutes and it stays soft like before startup.

The glow plug light comes up and turns off. I then crank and the engine starts with no problem.

Yes but I’m this case it smells more like unburnt diesel so my assumption is that if it was a cracked head and the coolant was getting in combustion chamber the smell would be different.

Thank you again for all your advice and ideas!

Based upon what you’ve said, I agree next should be a timing check. Get the locking pin tool if you can. Even if you’re not replacing the IP, there’s a definite help to knowing where your timing is.

I’m resealing my IP, so I set my engine to 14 degrees. Looked in the hole, I see the tab. All good, right? Nope. Couldn’t get the locking tab in the tool.

Turned the engine twice more and approached slowly. Finally got engagement at 16ish.

If your timing is out and/or chain is worn, you could be seeing poor combustion.

dieselbenz1 · #5 04-30-2023, 06:14 PM

You have bad fuel run it off a bottle of good diesel or run a purge.

giyom · #6 04-30-2023, 08:52 PM

@dieselbenz1 Yes bad fuel was one of my hypotheses, but I have been running the engine on a clean small auxiliary tank with fresh diesel and then 4 bottles of diesel purge and haven’t seen any improvement.

I had replaced the fuel filter prior to plugging in the aux tank with clean fuel and diesel purge so there is still a small chance that the fuel I am using is contaminated a bit from that. I can replace the filter again but that seems low probability given that there was no noticeable improvement.

So I am ruling out bad fuel at the moment.

giyom · #7 04-30-2023, 08:55 PM

@JHZR2 so you’re using the IP locking pin not to lock but as an alternative to the A/B test tool to make sure the pump is at TDC and checking that you’re 14 deg after TDC on engine.

JHZR2 · #8 04-30-2023, 10:28 PM

Quote:

Originally Posted by giyom

@JHZR2 so you’re using the IP locking pin not to lock but as an alternative to the A/B test tool to make sure the pump is at TDC and checking that you’re 14 deg after TDC on engine.

I guess so. If you have an a/b tool certainly that is a good option to ensure timing is correct. I assume most folks don’t (myself included), so the locking tool gives a definite basis of when the pin is in the center of the hole, since you can be fooled in an optical illusion.

giyom · #9 04-30-2023, 11:32 PM

@JHZR2 I don't have the A/B tool and it's too expensive, but you can rent it from this company https://www.benzinjectors.com/product-page/injection-pump-timing-tool-positionsgeber

barry12 · #10 05-01-2023, 08:59 PM

I believe both these types of 603s Will run with the injection pump installed on the wrong stroke. Somewhat as you describe.

Get a mirror and get the tang in the injection pump visable. Then check to see if the valve lobes on the number one cylinder are tending to point upward.

Tang should be easy to locate with the timing marks on the damper pulley set to the right timing number. Tang not there turn engine through another 360 degrees and look for the tang again. Turn engine by hand in the same direction it runs.

What year of car is the 603 engine in? I ask as there are two 603 versions. Each version has to be looked at a little differently. The early one is a three liter and the later one a 3.5 liter.

Another test perhaps. If it is the 3.5. Get the glow plugs to stay on. Start the engine. White smoke has stopped post that. Just find the trigger point for the glow plug relay and install a temporary turn on circuit perhaps. You do not want to run the glow plugs too long.

White smoke is usually unburnt fuel. Should smell like that. Runs good was a lie from the vendor is almost a certainty. Sweet smelling can be antifreeze.

giyom · #11 05-01-2023, 10:41 PM

Quote:

What year of car is the 603 engine in?

1991. European model. Pretty sure it’s a 3.0 liters

Thank you for the tips @barry12

giyom · #12 09-11-2023, 03:22 PM

I was able to empty my tank completely and out fresh fuel. I emptied the tank by sending the return like to a plastic container instead of back to the fuel tank. It took about 1 hour to empty the 1/2 full tank with this method.

I am curious if anyone has an idea of what is the reasonable flow in returned fuel or whether this is high and confirms that the fuel is not getting burnt as I suspect.

https://youtube.com/shorts/BKVwQKYXHZg?si=-Zekvv4LbSDRGw2Y

Unfortunately even with fresh fuel the smelly smoke is still there.

https://youtube.com/shorts/QNir0INBjlI?si=ovbRZILRknO9SPFw

I still think of a timing issue but next on my list is compression test and timing test/adjustment.

JHZR2 · #13 09-11-2023, 06:42 PM

Quote:

Originally Posted by giyom

I was able to empty my tank completely and out fresh fuel. I emptied the tank by sending the return like to a plastic container instead of back to the fuel tank. It took about 1 hour to empty the 1/2 full tank with this method.

I am curious if anyone has an idea of what is the reasonable flow in returned fuel or whether this is high and confirms that the fuel is not getting burnt as I suspect.

https://youtube.com/shorts/BKVwQKYXHZg?si=-Zekvv4LbSDRGw2Y

Unfortunately even with fresh fuel the smelly smoke is still there.

https://youtube.com/shorts/QNir0INBjlI?si=ovbRZILRknO9SPFw

I still think of a timing issue but next on my list is compression test and timing test/adjustment.

The fuel pump should flow massively more fuel than the engine burns, so measuring return fuel wouldn’t really be an indicator of much.

About 1L/min is what I measured.

Lift Pump Flow Rate Spec?

So then call it 4 mins per gallon, 40 mins for 10 gallons?

Seems you’re about good with fuel pump flow. Maybe not pressure though. Check that.