I have recently developed an intermittent smoking/rough idle/misfire issue in my OM603.
From DEAD COLD it acts like it wants to stall out but it never does, it runs like absolute garbage for 30-60 seconds; misfires, puffs smoke, before eventually smoothing out and pretending nothing happened.
If theres even a little heat in the engine it runs PERFECTLY, so yay?
I've had this misfire for about a year but it was very very mild and would last 10-15 seconds MAX, but about a week ago it started to do this:
Bear in mind it has a full can of "Diesel Kleen" in the tank, it actually started better in the video than it normally has this past week.
When did they get checked... recently? Did you double check yo be sure the wires are good and snug on the plugs? Maybe more are getting weak. And the week one is bad now.
Especially, seeing as it runs better when it get some heat in to it.
I don't know the maintenance history, so if the following has been done disregard.
Checking the chain stretch.
Glow plugs are cheap and easy to replace on this engine, maybe $6.00/each for Bosch from Rock Auto.
I'm not sure I understand what a "weak" glow plug is, unless the resistance is off. If it is, the glow plug is close to failing, as they typically either work or not - there's really no in between that I know of.
Be sure to ream the holes before installing the new glow plugs, and use plenty of anti-seize.
Awesome video, you make it very straight-forward to diagnose and repair this common problem. Thanks a bunch! I may just tackle this myself (and ignore the mechanic that said that they are OK. At the very least, at least I can check them with a test light, to rule out a bad plug!
It could be the glow plug, but I am thinking that the injectors may have become far out of spec and are no spraying as well as they should. Cold engine on a cold day, you have one or two injectors soaking the cylinder and overloading with fuel, on a compression stroke, you get a mistimed light off.
What you describe sounds exactly like what my car does. While I had the glow plugs checked last year, I don't have much faith in the shop that did the check. I believe that is probably what is going on. My hypothesis is this: when it is running so rough and billowing smoke, some of the cylinders aren't firing yet, thus the smoke, (unburned fuel ), and the roughness is because of the uneven firing. Once those cylinders warm up some and catch, it clears and runs great. Makes perfect sense, since there are no spark plugs in these beasts. For me, I had all of my injectors rebuilt with new nozzles, about two years ago, so I doubt that to be the culprit, although I guess it could be.
If you want to do a better electrical test, instead of using a small test lamp like I did in the video, use a bigger lamp (like a sealed beam headlight, etc). If the plug can't pass enough current to light the lamp it's bad.
I've never seen a bad glow plug that wasn't an open circuit. Not to say it can't happen, but... I'd say the test light is a definitive test (unless you forget which ones tested bad... )
I have no more than 3 working glow plugs. My "Wait to start" light acts normally. A year or so ago, when I probably had 4 working, it still worked normally, except it would come on sometimes while driving. Conclusion: the wait to start light is not a reliable diagnostic tool. Also, my glow plug relay is on the false firewall.
OK, problem #1. They aren't Torx. They are Allen (hex) drive. (Maybe just a miss statement on your part...) Second, what you need is a ball end Allen wrench. Not sure if you can get them in square drive or not, but you really don't need that.
The ball ends allow the tool to swivel right at the socket head, so you can have considerable misalignment, or, you can use the other end which doesn't stick up as far as all that hardware in the video.
Bought ball end hexes, mother of god they are pricey.
All of the top end of the manifold where the "intake horn" meets the intake manifold are 5mm, the rest that are bolted to the head are all 6mm.
Access is an absolute PITA, even WITH the ball ended hexes.
I've gotten everything torn down and my stupid a** thought I could reuse the old intake manifold gasket. Needless to say NOPE. New ones on the way! (I'm also going to service as much of the vacuum hoses as I can "while I'm in there")
Access to the glowplugs is impossible without -Deep Sockets -Ball End Hex Wrenches -Swivel socket extension -"regular" wrenches -rubber mallet -Breaker bar (or pipe, I used a pipe)
I had to use all of these tools to get everything apart, mostly because access is not great even with the intake manifold off.
Does anyone have any idea where to acquire some new accelerator linkage socket connectors? One of mine is cracked pretty bad and would like to replace all of them, if at all possible...
One of my glowplugs was BROKEN, and I think they might all have been on their way out since they all look pretty bad, here's some pictures:
Is that socket the one that goes to the cruise control actuator? I broke that on my car too... years ago... it's been replaced with a piece of bailing wire
On the glow plugs... plugs with worn tips can indicate worn injector nozzles. Have yours ever been done? The single stage pintle injectors our cars use are some of the easiest to set up. If it's been over 100,000 miles since the nozzles were done a fresh set of Monarks would probably make the car get power, start easier, and get better fuel economy!
Best to have a shop install the nozzle tips, unless you want to get the pressure testing device, shim kit, and surface lapping tools.
Rebuilt injectors with new (Monark) nozzles calibrated to within 50 psi (or less) or so of the set will make a significant difference in performance and running.
I just did mine about six months ago, and the car has an idle that is as smooth or smoother than any of my gas MBs (M119s/M103). I was hoping for a major gain in fuel efficiency, but I didn't get that - but I did get a slight gain of maybe a mile or two per gallon and much smoother engine operation.
And while this is a little late, invest in a can of Kroil for any of your part removals on a car of this vintage. This stuff is near magical when it comes to freeing up or just loosening fasteners. When I'm going to do some work on the car I give everything a couple of shots a day or two before I start, if possible.
If it does it at idle you can crack the lines to each injector, one at a time. This has the same effect as pulling the plug wire on a gas engine; that cylinder stops firing. If you find one that makes it even out or doesn't have any effect then you've found the bad cylinder.
It'll weep a little fuel when it's loose, but nothing overwhelming at idle.
I have recently developed an intermittent smoking/rough idle/misfire issue in my OM603.
From DEAD COLD it acts like it wants to stall out but it never does, it runs like absolute garbage for 30-60 seconds; misfires, puffs smoke, before eventually smoothing out and pretending nothing happened.
If theres even a little heat in the engine it runs PERFECTLY, so yay?
I've had this misfire for about a year but it was very very mild and would last 10-15 seconds MAX, but about a week ago it started to do this:
Bear in mind it has a full can of "Diesel Kleen" in the tank, it actually started better in the video than it normally has this past week.
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