My wife's 1979 240D (432k) has been running very well. I replaced the glow plugs about a year ago and it starts easily even in cold weather. I replaced the starter about 2 weeks ago because the old one lost the solenoid bolts and broke. The car has very little smoke and good power.

The car started normally and about a mile from home,
while she was accelerating up a hill to pass a cement truck, it just quit. According to her, no coughing, chugging or any engine noises. She said there was a cloud of black smoke as it died. She said she wasn't sure though if the smoke wasn coming from the cement truck or the car. She walked home about a mile and got me to go look at it. When I tried to start it, the battery was dead and it wouldn't turn over. I got it towed home and put jumper cables on it. It turned over normally, started and ran for about 20 seconds then died. The battery is less than a month old. The alternator about 2 years. The alternator was working at the time I replaced the battery. The old one had 2 dead cells.

Thinking it seemed to not be getting fuel, I replaced the filters and primed it with the manual pump. Now, it simply won't start. Sometimes it kicks like it wants to start but nothing. I tried spraying some starter fluid in the air intake but still nothing.

The glow plugs are getting electricity and I'm pretty sure they are ok. The car started normally on it's last trip.

She said the only abnormal thing it has been doing is running-on for the past month.

I visually checked all the vacuum lines and they seem to be fine.

I don't think the problem is major (at least I hope not), because of how well it has run since we got it 150k ago.

Any ideas of what can be wrong or things I might do to find out what is wrong would be greatly appreciated.

Thanks,
David Scott

I would start by pulling the valve cover off, taking the crankshaft bolt socket and turning the engine over manually while watching the timing chain and valve train to ensure that everything moves the way it should. It is the "cranked up and ran for 20 secs" sentence that makes me think that you should be allright as far as timing chain/cam/valve train goes but I would check this stuff first. Make sure you compare the timing mark at the camshaft and the crankshaft at TDC on the #1 cylinder while looking around in there. I would go from there to the fuel delivery system/fuel quality.

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Jim

Sounds like a fuel supply problem. Does fuel flow from the supply line if you remove it from the prefilter (inline filter)? Does the hand pump feel like you are pushing fuel when you pump it? Does fuel (and/or bubbles) move up the semi-tranparent fuel return line (from the motor side of the pump to the fuel filter)while pumping?

If these last events don't happen and there is fuel at the supply pump, I would expect the replacable check valves inside the feed (supply) pump

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Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician

I checked the fuel supply. It is getting fuel to the injectors. There is no vacuum developed during cranking at the vacuum thing on the end of the injection pump. I don't know if there should be any at that time. The next thing I plan is to do as engatwork suggested and check the timing. I tried the other things first just because they were easier.

David

how long has it been from when it quit running to the last fill up - maybe a bad dose of fuel? How bout fuel filters - how long have they been in there? Are you able to check the "start of delivery" timing. Also, while you are in there nosing around with the valve cover off take a really bright flash light and inspect down where the chain guides and tensioner are located. See how they look. After thinking about it some - I don't think it would turn over if it was a broken chain type of problem. One of the techs will have to verify this. To me it is pretty simple to pull the valve cover. Be careful too in trying to start it alot - I burned up a starter on an old Chrysler that would not start one time.

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Jim

It is simple to pull the valve cover, but to get a socket on the crankshaft, I have to pull the radiator, the fan and the AC cooler. I can almost see the timing marks, but they are dirty and I can't reach them. Other than that, I don't see how I can get to TDC to check the camshaft mark.

I wondering if the chain stretched enough to jump a tooth, or if the tensioner came loose. I don't know if either one is probable.

David

David,

Believe me, it is possible to get a socket on the crankshaft bolt without pulling the radiator, etc.
I use my injector socket and a large rachet wrench to turn mine.

As for cleaning the timing marks, crawl underneath the car from the front and the marks will be right there in front of you (if the crankshaft is in the right position, otherwise turn it as above) for cleaning.

Hope this is of some help. Good luck.

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Ted
1979 240D
165,000 miles