Blue smoke from the M119!?

[mb280sel1985]

I've had a few situations where my 500E has been sitting for a couple of weeks. When starting it up, it struggles a bit to get up at a normal idle speed, and engine shakes. Takes about 3-5 seconds before coming to normal.

When I look in the rear mirror there's quite a bit of smoke back there. And it is blueish.. But the smoke is gone within 10 seconds.

There's a minor tikking noise from the left block (close to always); right one sounds ok. The other day I started it after sitting 4 days. Now this time I hear some light knocking.

Checked the oil cap to see if there was any paste residue from coolant leaks - but it's clean as honey. I change oil Mobil1 5W-50 Rally Formula every 6-8000 km. There is no noticable track of oil in the coolant reservoir either.

Is it really possibly to get blue smoke damping from a rock solid M119 engine?? I thought these V8 blocks were immortal :-|

It's got 226K KM on the clock.

I've heard someone talking about fuel dripping into the combustion chamber, which can be fixed by replacing gaskets at the plugs.. Please correct me.

By the way I got confirmed from a diagnosis expert today, that my upper wiring harness definitely needs replacement asap - 124 440 20 06.

Could failing oil tubes create this problem? Lean running? Failing cylinder? Blue smoke?

What to do? Hope it doesn't break down dying on me

 

[gerryvz]

Is the car only blowing blue smoke upon startup? How about when you are sitting at a long traffic light or idling for a period of time. When you pull away, does it give off a bit of blue smoke? How about when you're moving and let up on the throttle? To really see what is happening, it would make good sense to have someone follow you for a few miles in all types of driving and let you know what they observe coming out of the tailpipe, and when.

I think the two problems are unrelated, first of all.

My best guess from the stumbling is that the car is losing fuel pressure and/or is getting flooded as it sits. I'd start with a fuel pressure test to ensure that the system is holding pressure to the proper specification. It is entirely possible that your check valves in the ends of your fuel pumps are bad, or your fuel accumulator or fuel pressure regulator are worn out. None of these are expensive nor difficult parts to replace, although you have to be very careful working around gasoline. That said, all of these items help maintain proper pressure in the fuel system of the car. I would start with the fuel pressure regulator (easy to reach and relatively inexpensive) which is actually a common item to weary out when you have significant mileage on the car.

The other thing it sounds like it could be would be a faulty/leaking fuel injector(s) or a leaky cold-start injector. The shaking and roughness at the start means that there is extra fuel sitting in the cylinder that has to be burnt up when the car first starts, and it takes a few seconds to work through the fuel when this happens. You can have your injectors removed and tested, and may not be a bad thing to do. Though I have to say, the electrically controlled injectors of the E500E LH system, though expensive, don't really fail or wear out that much. They tend to have a pretty long service life ... though they can and do fail with use. Something to check out.

The blue smoke indeed indicates that oil is finding its way into the combustion chamber. Failing oil tubes don't cause this problem -- rather they cause a ticking noise that is very audible. I think you need to have a competent mechanic look at the car to see what they can find. I haven't heard of the plug gaskets causing fuel to drop into the chamber, and if it did it wouldn't cause blue smoke. Only oil causes blue smoke. Although I've really never heard of it happening on an M119, I'm wondering if your valve guides or valve guide seals are worn out (similar to the M117, for which this is a common problem after about 140-150K miles). The only other way oil could get into the combustion chamber, if it's not coming down from above, would be to come up from below, and that would be your rings aren't providing the proper seal.

I think the main thing you need to do is

a) find out when this blue smoke is coming ... how frequently and under what characteristics (after idling, upon acceleration, deceleration, etc.)
b) perform a compression check AND leakdown test to determine the condition of your top and bottom end sealing

The compression/leakdown test will pretty much tell you everything you need to know, and is not a horribly expensive thing to have a competent mechanic do. Putting a borescope down into the cylinder through the plug holes wouldn't be a bad thing to do either, so you can take a look at the cylinder walls to determine their condition.

Keep us informed about your progress in the diagnosis.

Cheers,
Gerry

 

[DerFuror]

...When I look in the rear mirror there's quite a bit of smoke back there. And it is blueish.. But the smoke is gone within 10 seconds.

Very likely valve seal(s). Compression/leakdown test will pinpoint which cylinder. Although if valve seal(s), consider replacing them all.

There's a minor tikking noise from the left block (close to always); right one sounds ok. The other day I started it after sitting 4 days. Now this time I hear some light knocking.

Very likely a failed cam oiler tube. Remove left valve cover & inspect.

Have new valve cover gaskets on-hand prior to opening up the valve covers. Replace the old valve cover gaskets after the other work is completed.

 

[mb280sel1985]

Hey Gerry, thanks a lot for a very helpful reply.

The car is blowing blue smoke only on startup, and only after sitting for a week or more. On a normal week-end rest from friday afternoon to monday morning, there is no sign of blue smoke nor rough startup. Exception is when ASR lamp goes on (6/10) and into limp mode of course. But no blue smoke, and nothing when driving, stop/start in traffic light, nor anything when moving and letting up throttle. I've been driving behind the car a few times, looking for blue smoke after seing blue smoke from startup after it sat for a while.

When you say moving and letting up the throttle, the car pulls and pushes as if something is not regulating quickly enough. I also have miss-outs around 4500rpms after kicking down giving full throttle. I believe this could be the engine harness though.

You say the fuel pressure or sensors may be bad/incorrect - I can often (intermittent) hear load noise from fuel pump in the rear especially, and the engine feels "pressurized".

About leaking cold start injector - It does not act up like this always - if sitting just a day or two there is no issue. Wouldn't a leaky injector be static and not intermittent?

So the ticking noise (not always there but often) is the oil tubes.. I know they've most like not been replaced ever.

The valve guide and seals - I've read these are notoriosly breaking down in the M119 - is this true and what's the effort/price of replacing these? And I understand from your post that this may cause oil to wander into the c chamber, again causing blue smoke? Is this only on startup or also while driving? Again, these haven't been replaced either from what I know. Had the car since 160k KM..

From your point a) above - there are no other signs regarding this, other than blue smoke on startup for 6-10 seconds and some rough idle in that same time period.

What should a compression/leakdown test cost? The specialist I saw yesterday said he was unsure if all cylinders were running at all times..

Thanks so far

 

[mb280sel1985]

Sorry DerFuror you beat me to my post

 

[gerryvz]

Like I said, I think you need a compression & leakdown test, and to pull any codes from the car, as baseline data to help diagnose any issues. At least then you know what you are dealing with. Then, you need to have them also connect the car to a handheld tester or Star Diagnostic System to get live data. This will clue an experienced tech in as to how the car is running on a cylinder by cylinder basis, to see that everything is working and firing appropriately.

I would hate to venture any guesses until you have compression/leakdown information, codes, and live data. But it's safe to say that the blue smoke, coming after sitting, is very likely from valve guides/seals from oil leaking down into the combustion chamber, or perhaps a bad head gasket?. Oil isn't going to migrate upward through then piston rings when the car has been sitting ... it's going to migrate downward. I haven't heard much about M119s having a problem with valve guides and valve stem seals, particularly lower mileage examples (and even higher mileage examples). Doesn't mean it's not an issue, just not a super common one, as opposed to what you see with the M117 valve guides/seals, which happens to EVERY engine by 170-180K miles no matter what.

A compression & leakdown test shouldn't be more than 2-3 hours of a mechanic's time, at the most. It would be money well spent in conjunction with a SDS or HHT being hooked up to the running engine to pull codes and monitor the live data. A half-day of diagnostic time will very likely tell you what you need to know, and what you are facing.

This could also be something very simple like the spark plug seals. All of this discussion about valve guides, valve guide seals and piston rings is a moot point without information and observation from an experienced mechanic with the M119.

CAVEAT: If indeed your valve guides are bad, the heads will have to come off the car to replace them. I don't know what the book time is on the M119 to R&R the cylinder heads, but I know it's 25-30 hours on the M117 and my best guess is that it would be at least this much if not more for the M119 given its increased complexity over the M117. I'd say you'd be looking at least USD $5,000-7,000 to do this work, labor, parts and machine shop time included. Again though, you need to get a thorough, data-based diagnosis of the issues in hand so you know really what you are dealing with. None of this may be necessary and it may well be something simple. Find a good mechanic familiar with these engines to test, advise you and do the required work.

Cheers,
Gerry

 

[Cadence]

Very likely a failed cam oiler tube. Remove left valve cover & inspect.

Have new valve cover gaskets on-hand prior to opening up the valve covers. Replace the old valve cover gaskets after the other work is completed.

I would like to know more about this failure.

Does anyone have a photo of a cam oiler tube? What causes an oiler tube to make a ticking sound? What part of the tube fails?

 

[gerryvz]

I would like to know more about this failure.

Does anyone have a photo of a cam oiler tube? What causes an oiler tube to make a ticking sound? What part of the tube fails?

http://www.k6jrf.com/MB_lifter.html

New parts:
http://www.autohausaz.com/search/pr...ne Parts, Seals & Gaskets&gid=11984@Cam Oiler

 

[gsxr]

A compression test wouldn't hurt, it would mostly verify the bottom end is tight, but as Gerry explained the oil is most likely dripping down from somewhere up top (valve seals or guides). The compression test (and/or leakdown test) may show everything is perfect, which again points to something above the valves. If it's just a little smoke at startup, I'd ignore it until it gets a lot worse, as the cost to repair will be $$$$.

BTW, what brand/viscosity oil are you using? If it's thin stuff, I'd switch to something thick and see if that helps any. You may be able to delay the repair for several years if the problem is not severe at the moment. Gerry's estimate of ~$5k USD for the valve job is about right. BTW, where are you located? (Hint: You can post this in your profile under "Location").

 

[mb280sel1985]

This could also be something very simple like the spark plug seals. All of this discussion about valve guides, valve guide seals and piston rings is a moot point without information and observation from an experienced mechanic with the M119.

I meant the spark plug seals when I said replacing "gasket at the plugs" sorry for not being precise.
So replacing the spark plug seals COULD fix the blue smoke then. How to go about checking these seals?

Like I said, I think you need a compression & leakdown test, and to pull any codes from the car, as baseline data to help diagnose any issues.

This means I will have to replace my badly degraded upper wiring harness first. Because we kept loosing live data while doing the diagnosis yesterday.

The specialist was using BasicDiagnosis SBD-102 because he's Star Diag HHT was dead. This SBD tool was very informative - very neat tool, but of course 10 years old and not quite as advanced as the latest firmware on the Star HHT. He will call me as soon as the Star is alive up and running again. So my hopes for the best on that!

Gerry, I like your theory of the oil migrating downwards when at rest. I've had the feeling that it must be something dripping from above, since there's no sign of issues with the smoke in any other situations. Never heard of a M119 with head gasket issues though..? Is this as rare as the valve guide seals/stems breaking? I may be mixing the two - guides vs oil tubes - but isn't it true that (one of them) were of metal up to and including the '92, and then from the '93 they made them into platic?

I really don't hope we are talking off/on with head gasket and a valve guides. I actually did an inquiry to the dealer about this back in february. What comes to mind is that i requested a price just because I in fact read about bad guides, seals and tubes and also the chain going loose. I remember they sent me an offer around 55-60000 NOK (10k-11k $'s). Yes, it's extremely high priced at our dealer here (total monopoly). Of couse I would order from USA though

BTW, what brand/viscosity oil are you using? If it's thin stuff, I'd switch to something thick and see if that helps any.

I use Mobil1 only and the Rally Formula all year which has viscosity 5W-50. I hear it's the most advanced oil for "racing engines". I change before 8k KM (every 4000-5000 miles).

Is this oil thick enough? The oil pressure needle is almost constantly at max (3), but goes down to 2 psi if in D and engine runs at 500 rpms. I've occationally seen 1 psi if engine goes to 107 celcius (fans kick in), and the ASR limp mode is on, but this is rare - only when shifting reverse/drive and engine sometimes even hit 400 rpms or so.

By the way gsxr - I'm from Norway. So temps are 20C in summer (California wheather) and below 20C in winter.

 

[samiam44]

I think you need more diagnostics ....

I have encountered some strange senerios which are rare.

1) low mileage porsche motor where the guide cracked ~ 40k miles.
2) v/g loose in head.

Check the bottom end first.


Michael

 

[mb280sel1985]

I wasn't sure I was going to post this photo here, but what the heck.

During our diagnosis this week (which we had to give up due to bad harness), the "Actual value potentiometer (N16/1r1)" was staying at 4.3 V until gas pedal was pushed about 60% down. The one below - "Set value potentiometer (N16/1r2) was always moving when we adjusted the pedal position. The value meets 4.3 V when pedal is all the way down (kick down).

Isn't the N16/r1r (actual) supposed to decrease in Volts as soon as the throttle pedal is applied? Just like the N16/1r2 increases in Volts?
Be aware that ASR lamp and limp mode were active.

Taken the bad engine harness in consideration, I just wonder if the potentiometers inside the EA are acting normal or not.

After fiddling with the wiring harness, resulting in brittle bits of plastic and insulation going apart, and parts of ground cable being butt naked showing just thin metal wires, the engine is acting up like crazy. Idle is fluctuating from 300 rpms to 2000 rpms, driving the car is almost impossible because it may suddenly stop or rattle away. When it stopped today, I tried to restart but engine was overflooded with gas and gave away lots of grey/black smoke. Car runs way too rich making only 8 miles/gallon. But then after a 4 hour break this afternoon everything was basically back to normal - ASR lamp on, no rattling, no acting up, no black smoke and no shut downs..

Sounded and acting if it was running on only 6 cylinders.

Could the wiring harness do all this, or has it (will it) kill modules/sensors/etc?

 

[gsxr]

Isn't the N16/r1r (actual) supposed to decrease in Volts as soon as the throttle pedal is applied? Just like the N16/1r2 increases in Volts?

Not necessarily. Remember that the throttle does not start to open (mechanically) until you push the pedal down approx 50%, so this could be totally normal.

I would not drive the car until you get the harness replaced. It sounds like this is a pretty severe case.

 

[DerFuror]

After fiddling with the wiring harness, resulting in brittle bits of plastic and insulation going apart, and parts of ground cable being butt naked showing just thin metal wires, the engine is acting up like crazy. Idle is fluctuating from 300 rpms to 2000 rpms, driving the car is almost impossible because it may suddenly stop or rattle away. When it stopped today, I tried to restart but engine was overflooded with gas and gave away lots of grey/black smoke.

Could the wiring harness do all this, or has it (will it) kill modules/sensors/etc?

Oh yeah.
You'd best STOP fiddling with the harness
& just replace it before everything it's connected to goes up in smoke...

Don't drive the car until you replace the harness
or you'll end up very, very sad (& broke)!

 

[mb280sel1985]

Ok thanks! The harness was ordered today. Takes about 7 days from USA to Norway.

Hope I didn't ruin any $$ parts already. It won't be driven until fixed.


One question though; is the harness I bought of any better quality than that of the factory from 1993? The part number to buy is the exact same.. One would think they would've come up with a replacement part number after 17 years, if you know what I mean

The one I ordered was 124 440 20 06 - the same as mounted in the car..

 

[mb280sel1985]

Here is a video of the engine going bananas

[youtube]ZTfQY42wBNY[/youtube]

 

[gsxr]

One question though; is the harness I bought of any better quality than that of the factory from 1993? The part number to buy is the exact same.. One would think they would've come up with a replacement part number after 17 years, if you know what I mean.

Yes - the new harnesses are the same part number, but produced with improved insulation. The new ones last much, much longer. My '94 got a new harness in '98 and the second one still looks like new despite being 13+ years old.... while the original failed in 4 years!