Skip,

If you can get a positive fix from another shop, it time to go back to the original shop and demand a big refund.

To spend $1000 with no results is ridiculous.

Has a compression (wet and dry) test been done with the engine cold? Can you track the miss down to 1 cylinder or is it random?

I agree that you "certified" mechanic leaves a lot to be desired. He should have done the above tests before replacing all the injectors. Also, the injectors should have been tested before replacement. That's the trouble with many mechanics, they just replace parts until the problem is solved and you end up with paying to replace good parts.

P E H

Guys, in the interest of saving space, this is a multi response email.

TheVirginiaDude, thanks for clarifying the color of exhaust. No doubt, my bluish color is the result of oil burning and I'm going to insist on a compression (wet/dry) test.

Aaron, as a factory recall, the Mercedes dealer replaced the trap oxidizer back in '96 and it made a world of difference in acceleration. After the repair, she ran like a scalded rabbit. Couldn't believe the difference.

Ken300D, with the old glow plugs and the new, on a cold engine start, the engine kicks over quickly but it's accompanied by a definite engine miss. If this was a "normal" occurrence from day one, it wouldn't have concerned me. But since it first started about two years ago, it was sporadic and only occurred during the winter and I thought it was weather related. Now, it happens no matter how hot the outside temperature is so there's no doubt the problem has become progressively worse. After about 5 seconds after a start, depending on how long it's been since I last started the car, the exhaust becomes a bluish color which then disappears along with the miss when I increase the RPM's.

The more input I receive, the more I'm leaning towards a bad glow plug relay although I'm not eliminating any advice. Although he doesn't know it yet, I'm firing my present mechanic of seven years because although honest, there's no doubt this problem is way over his head.

Additionally, I'm making a list of all the input I've received from this forum, will prioritize it, and take a printout of our exchanges to back me up because it's evident that you guys really know what you're talking about.

P.E.Haiges, my mechanic never did a compression (wet/dry) test and because of my ignorance about the diesel engine and the fact that I've only got 45,500 miles on the engine, it didn't dawn on me either to ask him to do one. I have no way of determining which cylinder(s) are missing. The longer it sits, the worse the miss. If I had to make a guesstimate, on a bad day, two cylinders miss on a cold engine start; on a normal day, one cylinder; and when the engine is warm, there's no miss at all.

Thanks all for your responses. Good info!

Skip

Blue smoke is oil, not fuel. Its rare for one of these engines to pump out blue smoke as valve seals last a VERY long time. Heads are a problem on this car, the original design was weak and MB redesigned a few times before they got it right. Head gaskets too. However, its almost always both. The head can crack here and there and the engine will run fine, but exhibit some odd behavior. For example, it may maintain cooling system pressure for weeks if not driven (overnight it should zero out). Test by pinching the upper radiator hose in the morning before you start it. IF its tight as a banjo string... A cracked head or bad head gasket can also be a source of low compression most noticably when you are starting the car. Head replacement is about $2000+ if you do the work yourself. Reputable shops do not sell used heads because originals were known for problems.

__________________
Brian Toscano

Brian,

Since the car hadn't been run in 24 hours, just did the pinch test and the hose squeezed in completely without any problem. Additionally, my coolant level is fine.

I've already decided that if the problem is a worse case scenario requiring major bucks to repair, I'm prepared to part with her. Would hate to but economically, it wouldn't be prudent to keep it.

Here's hoping the fix won't be too drastic. After all the information I've received on this board, am really looking forward to finding out what the gremlin is and I will let you all know.

Thanks!

Skip

DieselAddict,

Read the thread you referred me to and although I've heard of Redline I don't know where to buy it. Any ideas? My mechanic suggested that I use Pro-Gard by Chevron with Techron and said it would clean my injectors. But I think using these additives might be a mute point since I used them on my old injectors to no effect and I just had new injectors installed last week and the problem didn't go away.

Several people to include Jim Smith have suggested that my prechambers could be clogged with soot. I received another email today suggesting the same problem. He wrote:

"If you are not consuming engine oil - then you are not burning engine
oil! When a diesel starts cold - there will be a blue/white smoke
whenever the prechambers are NOT hot enough. If you allow the plugs to
glow for an additional 15-20 seconds AFTER the dash light extinguishes
and THEN start the engine and the smoke is reduced - THEN YOU HAVE JUST
SHOWN THAT WHEN THE PRECHAMBER IS A LITTLE HOTTER - THE SMOKE IS REDUCED
OR ELIMINATED! The glow plugs reach maximum temperature (about 1080 deg
C) after a total of about 30 seconds of glowing!"

I did exactly what he suggested and the engine started so quickly, that it startled me. Don't recall it ever starting that fast except when I first bought it. Additionally, there was absolutely no smoke, gray, white, or blue; again, the first time in two years the exhaust has been colorless, and although the engine was missing, it wasn't nearly as bad as it has been.

So, it appears he and Jim hit the bulls-eye on this problem. Now my question is that since high speed road trips haven't removed which is likely accumulated carbon/soot in the prechambers, would you suggest that I have the mechanic inspect the prechambers and if they're clogged, to them cleaned or is replacement the normal procedure?

Thanks,

Skip

Skip,

Sounds like you might be keeping that car for a little longer! Keep us posted on how it responds to the longer glow cycle over the next few days or so.

To clean things up a periodic run at wide open throttle after the car is fully warmed up will work wonders. These things love being driven hard, and if you don't normally do this the first time or so may be pretty unnerving as you clean the engine and exhaust system of accumulated, performance robbing black stuff. I have read other posts where actual chunks of flaming junk flies out the tailpipe.

You should be able to find Redline Diesel Fuel Catalyst in the nearest PepBoys. If you don't have one nearby, go to www.redlineoil.com and check their distributor locator. If there still isn't a convenient outlet, call them and they will mail the stuff to you for the normal retail selling price. If they suggest you go to an outlet that is more than a 5 or 10 mile drive tell them that is not convenient, which is what I do unless I need something quickly, and they will sell it to you rather than lose a customer.

Good luck and glad to hear the car is responding to your interest. Jim

__________________
Own:
1986 Euro 190E 2.3-16 (291,000 miles),
1998 E300D TurboDiesel, 231,000 miles -purchased with 45,000,
1988 300E 5-speed 252,000 miles,
1983 240D 4-speed, purchased w/136,000, now with 222,000 miles.
2009 ML320CDI Bluetec, 89,000 miles

Owned:
1971 220D (250,000 miles plus, sold to father-in-law),
1975 240D (245,000 miles - died of body rot),
1991 350SD (176,560 miles, weakest Benz I have owned),
1999 C230 Sport (45,400 miles),
1982 240D (321,000 miles, put to sleep)

DieselAddict,

Please disregard my last question as to what action should be taken if the prechambers are clogged. Jim Smith told me yesterday but I've received so much input the last two days, I'd forgotten. Sorry Jim. My synapses have temporarily shorted out.

Skip

Skip, I just wanted to make it clear to you that blue smoke doesn't have to be oil burning. It depends on how blue it is. If it's grey-blue then it's most likely unburned diesel fuel and small amounts emitted from a cold diesel is normal.

I started a thread a few weeks ago on engine "hiccups" during cold idle. Do a search if you want to look it up. My conclusion was that if you raise your idle speed a bit and run some Redline through the car which cleans the injectors and raises the cetane of the fuel, it'll fix the problem. If not, it might be something more serious.

__________________
2004 VW Jetta TDI (manual)

Past MB's: '96 E300D, '83 240D, '82 300D, '87 300D, '87 420SEL

Jim,

Will head to PepBoys tomorrow for the Redline. There's one right down the road from me. With the on target advice I've received in the last two days, I'd be nuts if I didn't try this product. Thanks and I'll let you know how things go.......that is if I don't get caught exceeding the sound barrier trying to unclog this baby!

Skip

Hey Skip, how's it possible that your reply to my post is above my post?

I didn't mention the longer preglow technique that others just mentioned here because I mentioned it in the thread that I referred you to. That's how I start my car every time when it's cold and it makes a huge difference!

__________________
2004 VW Jetta TDI (manual)

Past MB's: '96 E300D, '83 240D, '82 300D, '87 300D, '87 420SEL

DieselAddict.

I guess I forgot to tell you that my hobby is mind reading so I just answered your post before you sent it. Actually, noticed that last night after I sent my post and have no idea how it happened. Guess ol computer "Murphy" was playing tricks with us.

And yes, it was the "hiccup" thread you sent me to, Jim Smith's recommendation, and several others that prompted me to try the extended glow plug method. But being inquisitive and wanting to get things right, I knew something electrical or mechanical must be deteriorating that requires us to increase the wait time before starting. I got an interesting email from another forum which may possibly explain it. It reads:

"Skip, What I do is wait the extra 10-15 seconds EVERY time I start my 300TD cold - and when Linda or I forget - there is USUALLY a cloud! I'm NOT convinced that the problem is A prechamber - it MIGHT be all of the prechambers - or it MIGHT be some deterioration in several parts of the electrical system - perhaps the relay or perhaps the assorted connections of the battery, to the relay thru the fuse to the plugs and the battery to ground or the engine to ground!

Now that's an idea. This problem is MUCH more apparent on 6 cylinder diesels than on 5 cylinder diesels and it ALMOST never happens on 4 cylinder diesels (and I have some of each)! The current drain on a 4 cylinder diesel is about 60A after a few seconds and dwindles to about 32 A in 30 secs, while on a 6 cylinder diesel there is a 90+A initial current draw that dwindles to 48 after 30 seconds. If the same gauge wire and same sized battery were used (and I HAVE used the same size batteries in ALL the cars at least some of the time) the voltage drop to
the 6 cylinder glow plugs will be about 30% higher than to the plugs of a 4 cylinder engine and the heat produced WILL be reduced proportional to the voltage drop. I place of replacing ALL the electrical parts in the circuit and cleaning and tightening EVERY connection - I'd just let the engine glow for an extra 10-15 sec at cold startup. OH - one thing for SURE. Replace the 80 A fuse (if the old one is still in one piece and doesn't fall apart when you remove it - keep it as a spare)!"

Very interesting! I think he may have hit on the cause(s) and I'm going to bring that to the attention of the mechanic when I take the car in.

Skip

Would a can of BG 44K address this problem? I have never used 44K in a diesel, but it made a remarkable improvement in my wife's Subaru. The label on the 44K said that it works on gas and diesel engines, so I was thinking of giving it a try in my 1985 300D.

dculkin,

I obtained the following write-up on it:

"BG 44K quickly and effectively cleans the entire fuel system, including injectors, intake valves, ports and combustion chamber. Because it provides efficient removal of upper engine deposits, BG 44K reduces problems caused by deposit build-up such as engine surge, stalling, stumble, hesitation and power loss. It is an excellent aid in tuning an engine since BG 44K quickly restores engine performance and improves drivability. BG 44K added to diesel fuel will provide quick clean-up of coked fuel injectors. It is compatible with all fuel system materials and common fuel additives. Contains no alcohol.
DIRECTIONS: Add one 11 oz. can BG 44K to fuel tank at fill-up. ($19.95)"

Although I'd never heard of it, sounds intriguing but isn't cheap stuff.

Has anybody had any luck with it eliminating diesel engine miss/smoke on a cold engine start?

Skip

TheVirginiaDude,

Found it here:

http://www.ec-securehost.com/RynoPerformanceProducts/Featured_Products.html

Skip

Skip

You mentioned a little back in the thread that you intend to have your tech perform a wet and dry compression test.
The proper method to use on a diesel engine is a compression and a leakdown test. A wet compression test uses oil to seal the rings, and thereby determine whether is be rings allowing a loss of compression, or by default the valves.
Problem with the high compression diesel is that added oil to the cylinder will cause it to start running on occasion. It can then run away out of control until it burns up all of that oil, that it is using as fuel. Not a good thing to have happen to your car.