I have a 230K mile 400SEL (1993) that had been extremely well serviced by the previous (who was also the original) owner. The engine wiring harness was replaced about 5 years ago. The MB tech that had worked on the car for years confirmed that this car had no major issues and said he would have no trouble recommending anyone to purchase it. I purchased the car in September, put about 4000 miles on it and now it is dead.

The car would get to where when I would start it back up when hot, it would try to stall when I would accelerate, as if running out of fuel, then it would clear out and be OK the rest of the day.

I only drove the car on weekends, but one weekend when I first started it, it was missing badly and popping through the tailpipe and smelled like fuel. Few days later, tried again and it would not start. I let it set for about 4 weeks, came back, battery was dead as a door nail.

Charged it, tried starting again and then it would only crank (cranked very fast) and exhaust smelled like pure gasoline. Obviously not getting spark. I cant check any codes with the CEL on the dash, my CEL light does not even illuminate when switch is turned on (all other lights do).

I did that underhood check engine light test (someone told me about the box under the hood with the button that I could check) and got what I think is a code "5" and a code "25" or "26"... I cant remember.

Someone on another MB site said for me to check cap/rotor. I did, but could only get the driver-side loose/off. It was damp in there. I don't know why, the car has never been in any high water or had the engine wet.

Well I went and did some digging in the tool boxes and found what I needed to remove the cap and rotor. I only removed the one on the driver-side.

Not sure what I am looking for though. There appears to be some oil or moisture inside of the cap and I do not think that the part of the rotor button is supposed to look all chipped up like it is? I don't know where oil could be coming in from? Valve cover gaskets were supposed to have been replaced about a year ago.

Here are some pics, not sure how well they can be seen... can anyone tell anything by these? Is the rotor button burnt up?

Update - I had my dad look at the cap and rotor and he said he though they were OK, but inside of the cap was wet. Why would it be drawing moisture? I have never had the car in any high waters or washed the engine (obviously). We have had a lot of rain this spring, but that should not cause the car not to start. I dried the cap out with a cloth and put the car back together, same deal, will not start, will not even hit and it cranks fast and sounds strange... almost like a riding mower trying to start. I think something bad has happened.



















and despite being a 1-owner, well maintained car (serviced by MB techs) this is one greasy engine... needs a professional detail



Thanks in advance!



Any other suggestions to what may have happened?

No one?

see if cams turn when someone cranks engine.other than that you need air,fuel,and spark to run a engine.check for thoose.

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1999 w140, quit voting to old, and to old to fight, a god damned veteran

If it turns fast and makes strange noises you timing gear may have been broken (chain or tensioner).
Unfortunatly that is not easy to fix.

I would pull the valve covers and check the timing first, remove the plugs and turn the engine by hand (wrech on the cranshaft bold).

If the camshafts are turning but the timeing is off the next step would be to check teh valves. An endoscope is very handy for this.

If the valves are bent bur the pistons look ok hou may pull the head(s) and replace the valves and timing gear.

An aleternative is to replace the engine with a good used one (may be less expensive).

Rob

Thanks.

Well it sounds like a riding lawn mower trying to start.

I pray it is not the timing chain/tensioner... if it is, I will be furious, especially since this was was supposedly well serviced since new and over the past several years by the same Mercedes tech that told me out of his own mouth that this car was up to date on everything and was a solid car (less than 4000 miles ago).

All of these procedures are really too much for me to do, I am not very mechanically inclined and not much time to work on it. I guess another MB shop or European car shop will be checking this out as soon as I can get things worked out.

Would a tensioner/chain gradually go out over the course of a few months? This car has been doing this "missing" when first started for a few weeks, then it got worse and worse until the morning I went to start it and it was missing badly and popping through exhaust and smelled like gas from exhaust. When running at that point, I didn't hear any knocking or anything. After that, the car would not start and had that strange cranking sound. Then I took of the distributor cap and seen it was damp inside and dried it, but it still would not start.

If the chain/tensioner has broken, then I basically have a parts car that I paid $3300 for in September. I guess then its a parts car, then off to the salvage yard to be recycled. What a shame.

Oh well, live and learn.

It may be something else, hard to say from here, have a tech look at it.

If you are not very mechanically inclined buying a 20 year old top end and very expensive luxury car for $3300 may have been a bit risky decision . Things will go wrong with older cars and W140’s are not the easiest to fix.

You wrote that your car developed problems several weeks ago, and it seems that you were hoping they would go away. That is not how it works with cars, most problems get worse, to the point that it breaks down completely and is getting very expensive to repair.

Rob

Oh I know. I thought I was careful though. I knew all about the W140s and have owned several W126 models and never no problems. I thought I would be OK IF I purchased a well maintained, 1-owner W140 that had all of the service records. Plus, all of the big things had been done such as A/C evaporator, blower motor, heater core, engine wiring harness and much more. Then when the MB tech that had worked on the car for years told me that the car was mechanically solid, I thought I would be OK, at least for awhile. Guess not.

Yeah, the car developed a problem a few weeks ago, but it was minor and only when first started (basically only like it was starving for fuel or flooding on a "hot start" then it would go away, I guess I should not have waited so long. I was hoping to wait until I could have the motor mounts done and have it all done at once since the tech doing it is usually backed up like 2 weeks and it is hard to get in there.

All I know to do now is take it to the shop asap and see what they say, hopefully nothing major, if it is, lesson learned to never buy a W140 no matter how good the PPI sounds. Once repaired I don't know if I will even keep it or not, I may sell it.

UPDATE -

It started!! It started!! lol.

Anyway - I reconnected the battery to the Mercedes and thought I would just try it again. I cranked and cranked and cranked. The car finally sounded like it was "hitting" and wanted to start. FINALLY it did and when it did, it ran like a brand new car!! It sets there and idles smoothly, quietly and does not misfire when I rev the engine. Well at least now I know it was NOT the timing chain or tensioner being the issue, thank GOD! The exhaust still smells a little strange, almost like how some of the 80s-90s imported cars I had in the past would smell. Its a common smell I have smelled from exhaust, but I dont recall the MB smelling like that before. The car will start everytime as soon as I turn it off and try again... it restarted again and again and again.

The car still obviously has an issue, because as mentioned in the past when I would first start the car after stopping somewhere, the car would occasionally act as if it wanted to stall when I would depress the accelerator... it would eventually clear out. I am sure the CEL would be on if it would illuminate, but it dont. I did check the codes with the little box under the hood when it was not starting, but I was never able to figure out those codes. I think one was a "5" and one was "26"? I am going to check it again tomorrow when I get a chance.

The car is also getting low on fuel, so I am wondering if maybe when the car would not start before, maybe it had picked up some water or something?

Anyway, the car is running like new, setting in the driveway at least, lol. I am a little scared to get it out on the road, fearing it may conk out on the side of the road and I would have a big tow bill. I really need to plan on getting the car to a reputable MB mechanic and have it gone over. We only have one here in town, but he messed up my moms W126 in the past (fuel gauge - charged her $600 and it still does not read correctly). There are about 3 in the city 20 miles to our west. Time to save up and get it over there.

Thanks again for all of the help!!

To me this sounds totally fuel-air related. Cosider MAF and check the cold start system, or a combo of the 2.

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Prost!

Thanks. Well now that the car is running again, I guess I am going to try to get it to a MB mechanic and have it serviced. I am just glad the timing chain/tensioner wasn't broken.

Moisture in these caps is a very common thing if these cars aren't used for some time, they don't look so bad but do need to be dried out. The moisture is just condensation from the engines warming and cooling cycles.

__________________
600SEL '91
300E 4Matic '88
240D '83
280SE '77
350SE '73
The most complex systems can fail in the simplest way.
Contra verbosus noli contendere verbis, sermo datur cunctis, animi sapientia paucis.

i don't believe in the lord! He's never bought me a Mercedes Benz.

your problems sound like ignition coil failure if you get a hot start issue - generically, same for every other engine.

The lack or run and smell of gasoline is a case of no spark and the engine may start to sound like no compression (specially on anything larger than a 6 cyl) the gasoline leaks past the rings causing an oil washout and sometimes makes your engine feel such.

Your startup to a smell of rich gasoline burn smell is the gasoline in the exhaust cat converter igniting and being cleaned - it was collected when the engine was spinning with no spark - your cats would have been blazing hot at this time too. Best to drive it gently around the block and gun it hard a few times.

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2012 BMW X5 (Beef + Granite suspension model)

1995 E300D - The original humming machine (consumed by Flood 2017)
2000 E320 - The evolution (consumed by flood 2017)

My 92 400E does the same thing with dirty caps and rotors. A quick cleaning with emery cloth, then a squirt of QD electronics cleaner does the trick, they are very sensitive and seem like a catastrophic failure when bad. Replace them and keep an eye on them.

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John
2001 ML 320
1988 560 SL
2009 Toyota Tundra TRD
1992 400 E (sold '07) (bought back, '13)
2008 ML 350

Thanks for replies!

Yes, I was only driving the car on the weekends, so it had set for a few days, then when I started it, the car was rough running... shut her down and took another car... that is when the next time it would not start... until the other day when it finally did. The problem before was like if I was to go out in the car, go in somewhere like Subway for a sandwich, come back out and get in the car and start to pull out, it would be like it was running out of gas, when I would press the gas, it would stall like it was running out of gas, but eventually cleared out and would go on. Never did figure that one out. lol.

I may get brave and venture out in her tomorrow and see how it does and hope she don't conk out on me while I am out and about.