mystery smoke from 616 - PeachParts Mercedes-Benz Forum

ewmROVER · #1 11-14-2007, 07:52 PM

Hello all,

It's been a while since I've been on. I'll hopefully soon be back to finishing up my OM616 conversion into my 1967 Land Rover. I'm excited to get it done. Before I had to put the project away this spring, I was able to successfully get the motor in, wire and plum it up... it nearly killed my bleeding the fuel system, but finally got it to fire. It was such a relief! However, upon firing right up as soon as it finally got fuel to the injectors, it poured an alarming amount of white (if I remember accurately) smoke from the exhaust downpipe (unfinished exhuast). I observed this engine running before I pulled it from the wrecked 240d it came out of. The motor has been rebuilt on some level or another, and ran smooth with no smoke. Other than pulling it out of the 240d, I didn't do a thing to it. Got it bolted into the Rover, hooked everything up, and finally got it started. One thing to note - A VERY reputable Benz shop in my area recommended using starting fluid in trying to initially bleed the fuel system. With the motor firing and turning over, it would help the fuel along. I did this, being careful to not excessively use the fluid - just short little shots, letting it fire, then another small little shot.

Can anyone take a stab at why this motor is pouring so much white smoke? Upon getting it running, I let it idle for quite a long time, letting it get to temperature, and making sure everything was well. It regulated itself fine, I heard no strange noises, and the only thing I noticed was a leaky lift pump.

What do you guys think?

Thanks a ton for any input!

kerry · #2 11-14-2007, 07:55 PM

Does it have the early vacuum pump with the vent line going either to the intake or the air filter? If so, a bad diaphragm in the pump will cause oil to be sucked into the engine and burned.

t walgamuth · #3 11-14-2007, 09:16 PM

Next time use wd 40 to start an unprimed motor. It is just about like diesel. The starting fluid is too dangerous!

Tom W

ewmROVER · #4 11-14-2007, 09:25 PM

Specifically, what could have been damaged using the starting fluid, if that's what even happened. I HATE to think I ruined that motor already - the project's not even done! I'll use WD-40 in the future. I'm not near the project yet, so I can't recall if there is a vaccuum line going to the filterintake manifold or not - the motor is out of a 1980's 240d.

Thanks for the info...

Motorhead · #5 11-14-2007, 10:25 PM

You probably just need to run it for a while...longer than a minute or so. I personally have never had a problem bleeding a diesel. With a GOOD transfer hand pump you pump until you can hear the fuel bypass make noise on the pump. I crack half of the injector lines at the injectors and crank the engine with the throttle wide open. This will hasten the fuel flow to the "cracked" lines. I then glow the engine and feather the throttle and they usually start.
You are NOT supposed to use ANY type of starting fluids on any glow plug IDI type engine.

vstech · #6 11-15-2007, 12:08 AM

that "reputable" MB shop has a poor tech... IDI diesels are too fragile for ether...

psfred · #7 11-15-2007, 12:29 AM

It's not really a question of fragility as much as it is a question of compression -- a 16:1 engine won't fire ether until it hits TDC, if then cold due to low temp. With 21:1 and a prechamber, you get ignition temperature long before TDC, and if the glow plugs are hot, ether will easily ignite once the vapors reach the glow plug in ignitable mixture. Not good.

Air in the fuel system will cause white smoke, so will coolant entering the combustion chambers.

The damage you will do using ether is to break the ring lands -- eats the cylinder walls up and drops compression fast. Won't cause white smoke right off, but will later (and blue, as the oil burns).

Make sure you don't have leaks in the suction side fuel lines between tank and lift pump, else you will have fits and smoke.

Smell the smoke, too -- oil smoke smells like burning motor oil, unburned diesel like fresh diesel fuel mixed with something smoldering, and coolant smells of ethylene glycol.

Peter

winmutt · #8 11-15-2007, 12:43 AM

Did you check IP timing? Valve Adjustment? Air in the fuel lines? Did the smoke go away? Were the glowplugs operating properly?

t walgamuth · #9 11-15-2007, 06:31 AM

Quote:

Originally Posted by Motorhead

You probably just need to run it for a while...longer than a minute or so. I personally have never had a problem bleeding a diesel. With a GOOD transfer hand pump you pump until you can hear the fuel bypass make noise on the pump. I crack half of the injector lines at the injectors and crank the engine with the throttle wide open. This will hasten the fuel flow to the "cracked" lines. I then glow the engine and feather the throttle and they usually start.
You are NOT supposed to use ANY type of starting fluids on any glow plug IDI type engine.

If you are suggesting that wd40 is dangerous, then that would be incorrect. A diesel will run just fine on it sprayed directly into the intake, and with fuel from no other source will run on it as long as you keep spraying it in. Works like a charm.

Tom W

ewmROVER · #10 11-15-2007, 08:52 PM

Thanks for the input you guys... I know to never use starting fluid again - the bleeding process killed me. I finally found success cracking one of the IP fittings (to burp out a trapped air bubble), and quicky got fuel to the cracked injectors. After that the motor started right up.

I'm not near the project right now - it's been sitting for the summer and I'm about to jump back on it. I'm sure at that point I'll come up with a lot more questions!

I really hope I didn't damage anything using the starting fluid to crank the motor.

ewmROVER · #11 11-15-2007, 08:57 PM

I'm wondering if that leaky tranfer pump has anything to do with it - I think the fuel lines from the tank to the transfer pump should be sealed. The pump was dripping quite a bit while the motor was running.

Diesel911 · #12 11-16-2007, 12:05 AM

I have a comment not related to the engine. If the fuel tank in the Land Rover is a Zinc plated tank I was told in trade school that diesel fuel disolves the zinc which gets into your diesel fuel. I don't know about Land Rovers but most of the older American cars and pickup trucks have zinc plated fuel tanks.

Cervan · #13 11-16-2007, 12:16 AM

wd-40 is better to use because it uses propane to propell the liquid out. propane is commonly used to fumigate diesel engines.

ewmROVER · #14 11-16-2007, 01:42 PM

Diesel911,

I almost positive that the tank (a new replacement I installed during vehicle's restoration) is a standard steel tank. No zinc to my knowledge.

I'm just curious/concerned as I didn't finagle with the engine at all while taking it out of the 240d and installing it in the Rover. The only thing I can think of is...

-Damaged rings due to starting fluid use while bleeding fuel system.

-air leak in lines somewhere.

-air leak in transfer pump (which is leaking quite a bit).

-contaminants in Rover fuel tank (I drained as much gas out as I could using the bottom drain hole - I thought I got all of it out, allowing time for remnants to evaporate oit the top. But still, there may be some residue or something mixed in with the 3-4 gallons of diesel I put in to start the truck with.)

-Maybe the smoke will just clear itself out after being run for a while.

-I'm almost positive its not a HG issue - no smell, I don't seem to be losing coolant.

-could also be a timing (IP or valve) issue, although I don't know how that would have been altered from the original set-up in the 240d running smoothly and without smoke.

Maybe once I get it all buttoned up I'll take it to have a compression test.

Stevo · #15 11-16-2007, 02:02 PM

I just got done getting one going that had sat for a while. When I got it too fire the smoke was quite thick for a while due to some stuck rings but also all the oil I had squirted into the cylinders. Took it for a long hard drive, no more smoke.