I would go back and verify exactly if the loosening of the oil cap is really involved. With it on and someone cranking watch the shut off lever. Remove the oil filler cap and watch it again. Any difference and you should pay some attention to this item.

I base this on the two time occurance kind of ruling out coincidence maybe. Does a loose cap blow off when just cranking? I know it does not blow off when the engine is running. You mentioned that.

Run Diesel #2 or #1. get it running right before you switch back to veggie crap. oh i mean oil.

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Current
2006 E320 CDI, 57K bought at 67K "Liesl"
1986 190E 2.3-16, 198K bought at 56K "Brigitta"
1987 300TD (Chuggin Along), 292K "Friedrich"
1995 E320 Wagon, 200K "Louisa"

Past
1987 300SDL, (sold) 125K, bought for 1$ "Kurt"

Another thing I just thought of that happened to me that you can check-

You say you just did a valve adjustment. I would go back and double check the clearances and the pattern of exhaust/intake is correct. It shouldn't take more than a half hour to check. One time I messed up the pattern of E/I and I couldn't start my car in 20F weather unless it was plugged in. Redoing the valves correctly solved the problem.

__________________
2009 ML320 Bluetec
1985 300CD
1981 300TD

Past Mercedes
1979 300TD
1982 300TD
2000 E320 4Matic Wagon
1998 E430
1984 300SD
1980 300SD

Consider me #2 . I've always had problems starting in cold weather. Been trying all morning . I read this thread went back outside loosened oil cap and cranked . Starter speed picked up oil cap blew off smoked like a freight train out the valve cover but it started , same as it would when its warm. ???????


Oh car is 79 240D temp is a "frigid 40*" glow plugs recently changed as well as valves , breather tube wide open

Barry please explain what I'm looking for on the shut off lever .

I think your on to something.

i checked the glow plugs and they all seemed to measure up fine. i had some extras lying around including the two i pulled from my car the other day, and tried hooking them up to a battery and they all glowed. i noticed some took a little longer than the others to turn orange, but it was only a few seconds difference. im thinking ill pull all 5 tomorrow and put in the ones that heat up the fastest. they are all bosch or beru plugs. i picked up a set of drill bits and will try reaming the holes (very carefully) before installing the new plugs. i don't have access to a glow plug reamer nor know where i'd get one or i'd use that.

what does injector knock sound like? whats the difference between that and nailing? i don't know what noises are good and which are bad, does anyone have a video or audio clip that explains it all?

the car runs great in warm weather, it started fine today at around 40* F. i have been noticing ever since i did the valve job that when just pulling away from a parking space or going slow i have no power at all. it takes a while to get it going up to 20 mph, but once its up to speed it roars to life. The power above 20mph is much better than before the valve job, and ive noticed that it idles a lot smoother. I removed the bowden cable when i took the valve cover off, so maybe i might have just knocked it out of adjustment? i don't recall touching the adjustment screw on it.

elevation is 5280 ft and i believe its been 3 months since the filter was changed.

the oil cap does not blow off when cranking, it just rattles a little and oil squirts out onto the valve cover. Next time its cold out i'll try watching the shut off lever, to see if i notice any difference in its position. Just as an aside: I don't believe this situation would prevent starting. I think it would start for a second and then shut off. I have a 300D that doesnt have a keyed starter switch; its just 3 electrical switches soldered to the round connector, with a ball valve controlling the vacuum shut off. (bought it that way) I once tried starting it with the ball valve open, and it would start and then immediately die. (the ball valve kept the shut off valve engaged) only possible difference is that the shut off valve was under vacuum whereas in this case the shut off valve would need to be under pressure to be engaged, not sure if that would even be relevant.

Another interesting point is i'm on my 2nd engine for this car (nasty oil leak developed that i couldnt find). Before that mess, i had trouble starting my car where it'd do the same behavior of starting for a second and dying, it started when i removed the oil cap. see this thread.

i have added some diesel, not sure if its #1 or #2, im assuming they sell "winterized" diesel around here since theres been snow on the ground for the past month.

i double checked the valve adjustment after i did it, and i always look at the manifold so i know which is which.

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1981 300SD, 270K, two tank wvo system
1985 300D, 288K, california version
1985 300DT wagon, 315k, broken odo

Denver diesel is not winterized. The blends of winterized diesel get stronger the higher you travel into the mountains.

__________________
1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

That sounds like normal operation to me. The turbo doesn't kick in right away.

Since, this is your 2nd engine and you have the same problem along with your description of your starting/shutoff system, I am led to believe your odd start/shutdown system has something to do with it. As was previously stated, you should look at the linkages when trying to start to see what happens.

__________________
2009 ML320 Bluetec
1985 300CD
1981 300TD

Past Mercedes
1979 300TD
1982 300TD
2000 E320 4Matic Wagon
1998 E430
1984 300SD
1980 300SD

Biotour thanks for posting the oil cap thread did you ever come to a conclusion on what was causing the problem?

I went out again this morning took the cap off had it started within 5 min.

I had the same problem with the glow plugs slow ones were tossed . Mine wouldnt even start in warm weather back then. There is a thread on making a reamer from a drill bit using the old glow plug body, drilling it out for the bit and welding on a nut . search glow plug reamer I made one last spring. I kept the length as long as the glowplug to prevent damaging the prechamber.

Found the link : Homemade glow plug reamer?

im hoping the bigger battery fixed things. its been starting fine the past couple days, except today i had to crank longer than usual. it was odd- it started right up, then did the usual cold stumbling that it does (not sure exactly why). i put it in reverse and gave it some gas and it died. tried starting again and cranked for 5 seconds or so and just sounded like there was no gas. pumped the primer but there was no air in the lines. so i unscrewed the oil cap, and it fired right up. still continued to stumble for the next couple minutes but then was fine. and it wasn't even that cold out today!

i saw the thread about making the glow plug reamer- looks like he's using a 5/16 bit. i tried using a 1/4 bit and couldnt get it through. it felt like i was drilling into the metal so i stopped because i didnt want to damage the engine. im now thinking (and kind of hoping) that my glow plug chambers are just all gummed up with carbon and not working effectively, and thats why im having the stumbling and difficult starting when cold. I do run vegetable oil some of the time, only when the engine reaches around 90*C. id like to build that reamer but do not currently have access to a welder. is it possible to clean out with a drill bit? do i need to spray anything in there to loosen up the carbon before trying to twist the drill bit? like i said i tried it once with a 1/4 bit and didnt seem to be getting anywhere. the 15/64 bit went all the way through just fine

i never came to a conclusion about the problem with the last engine, it was just a one time occurrence and never happened to me again. it was very odd!

__________________
1981 300SD, 270K, two tank wvo system
1985 300D, 288K, california version
1985 300DT wagon, 315k, broken odo

Are you sure the vacuum is being released from the shut off diaphragm before you try to start it? It sounds as if there is still partial vacuum on the diaphragm in some conditions, hindering the flow of fuel thru the system. That could be why any slight pressure in the crankcase would activate the diaphragm fully.
Can you explain what mechanism you have in place of the ignition switch that releases the vacuum from the diaphragm prior to starting? It sounds to me from your description of the system that you have a valve which sends vacuum to the shut off valve to shut off the motor. You then turn this valve off to stop vacuum going to the shut off valve to start it. But stopping vacuum going to the shut off valve is not the same as bleeding off the vacuum you induced in the system. I think this is where your problem lies and it's why both motors had the same problem.

__________________
1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

Unfortunatly excess base pressure is shutting the fuel shut off valve off. There is excess pressure inside the crankcase when trying to start cold. It seems after the engine starts the blowby is less. Or at least lower so the shutoff is not activated.

If car was on vegatable oil at one time a good cylinder soaking with marvel mystery oil might loosen up the rings a little. All the smoke you see when the engine starts from the oil cap hole is excessive product getting by the rings.

The engine may have severe wear problems if the rings do not loosen up. My guess is once the engine is actually running the added combustion pressure is helping the rings seal somewhat bettter.

Pretty well would have to be or base pressure would still get even higher and shut the engine down. I often wondered if this was an intentional safety feature or accident of design. In theory if too much oil got past the rings the engine might self fuel.

Other than soaking the rings or a teardown after establishing by leakdown testing if problem is across all cylinders or perhaps only one. You can live with the problem by starting with the oil filler cap off and reinstalling it after the engine has run a little bit.

Honestly I feel it is not stuck rings but instead excessive wear in the engine. I can be wrong though. I would in fact be pleased if I was proved wrong in fact. I dislike stating the possibility of what amounts to bad news. Although with a little effort a good replacement engine might be found cheap with a little dilligence if a leakdown test indicates the need.

I wouldn't follow this line of analysis until it's shown that vacuum on the other side of the diaphragm has been allowed to bleed off.

__________________
1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

Good thought, try removing the vacuum line from the injection pump shut off before trying to start the engine cold. Especially if the car shows the ability to hold vacuum well. There might be a possibility of a vacuum defect aiding any blowby pressure. As stated earlier I would preffer to be wrong.

I will try that instead next time it's cold out.

__________________
1981 300SD, 270K, two tank wvo system
1985 300D, 288K, california version
1985 300DT wagon, 315k, broken odo