1997 E300D Won't Start

[AGx]

Maybe I just went to the cleaners. I was on a business trip 450 miles from home and I found this (really) new-looking '97 E300D on the bulletin board. I bought it with 90K on the clock for $13,500. The car had new tires, had just been detailed and it looks new inside, outside and under the hood... somewhat dirty underneath and no signs of rust anywhere. I drove the car for about an hour on the Interstate, surface streets and in the city and it ran and shifted perfectly and every accessory worked perfectly.

On the way home, when it got dark, I noticed that the low-beam detent in the Combo switch was shot and I kept flashing the hi beams when signalling lane changes. This was so loose that the hi beams sometimes come on when hitting a bump since the lever will bounce into the hi-beam or flash position as easily as it will stay in the low-beam position. No big deal but I'm embarrassed that I missed it. But I had no other problems *whatsoever* the car ran, drove and handled like new and I thought "what a great deal I just got."

Three nights ago (three days after picking up the car) the engine died while idling at a light. I turned the key off and back on and it started right up - this happened several more times that night, always at idle, always in gear, but not every time. The weather had been 95 and humid during the day and 78-80 and more humid at night. Next day, no problem, but today I cannot get this thing to start - it almost catches but just won't quite start. I've burned a tank and three-quarters of fuel (reserve light just came on for my second tank since purchase). I have no warning lights/information display messages.

Can anyone shed any light on this problem?

Thanks,
AG

[Matt L]

Check for air leaking into the pipes. The next likey suspect is the K40 relay module.

[nhdoc]

Could be leaking fuel lines or K40 Relay...do a search for those two items. Could also be fuel lift pump. If it is when the fuel is low I would first suspect leaks/pump and not K40.

None of these are killer jobs...nothing terribly serious or costly to fix and could be DIY if you are handy.

[aklim]

Any codes? Could it be the MAF? Maybe try cleaning that with a shot of Electric Cleaner?

What about the fuel lines? Are they leaking?

[AGx]

Now that you mention it, it seems that after that night, the tank was at about 1/4 full when the problem first occurred and I filled it up. Then I had to drive all over creation and the problem did not recur until I parked it overnight with the reserve light on - it had just lit. And, now the problem seems to be worse than it was that night - maybe a leak or pump problem getting worse... or not.

I'll look for a leak and see if that could be it first since spotting a leak would probably be easier than diagnosing a failing pump -- I'd think. Is the lift pump electric, does it run whenever key is on, on demand (pressure switched), or only when engine is running? Should I be able to hear it when I switch on the ignition before engine is started?

I don't have any messages on the in-dash display - would any of these problems show up with diagnostic codes? Is there a source for a reasonably-priced code reader that can interface with this car? What is a good source for service information - AFAICT it looks like those MB (Classic) CDs don't address newer models (at least '97 E300D)?

Thanks for the suggestions,
AG

[nhdoc]

You can test if it is a fuel problem by parking on an inlcine. If you park front up and it does not start but front down and it does then it is surely a fuel problem. Leaky lines will allow the fuel to run back to the tank which is worse when the tank is low because there is less back pressure to keep the fuel in the lines. Parking rear up helps keep the fuel pressure to the front. You can also look at the clear lines before you try and start it to see if they are full of air.

[Matt L]

AGx,

The fuel delivery volume is controlled by the computer, but only a few things are monitored. If you're leaking air into the lines, the computer won't notice.

Note that air leaking in is the trouble, not fuel leaking out (although if you have that, fix it, of course). Look at the plastic lines at the filter housing and watch for air when you crank it. They may be completely full of air with no fuel, since you are not starting, which should be evident even with the engine stopped. These lines get fragile (according to posts here that I've read), and you may be due for a set. Not very expensive nor very hard to replace.

The lift pump is mechanical, and thus only runs when the engine is turning. The hand actuator was deleted (long ago), but it's very similar to the older models.

Codes from the engine computer are available at the OBD-II port near the hood release lever, as required by US law. But only that computer is monitored by that port. For these codes, any OBD-II scanner will work, but the codes sometimes differ from what the Mercedes tool shows. The diagnostic manual shows both sets of codes, and their meanings. I doubt that you have anything to worry about there.

[AGx]

Those lines are somewhat yellowed (brown) so I wasn't able to tell if they were full of fuel or air and the car was in a spot where I couldn't get it pointed downgrade - as luck would have it, it was oriented uphill. Anyway, I put two 5-gallon cans of diesel in the tank raising the fuel level to almost 3/4 tank and after cranking for about 15 seconds, the engine started idling very raggedly and then smoothed out.

As a result, it really seems to me that an air leak into one of those clear plastic lines it the most likely culprit at this point since the car runs normally once started. I'm going to try to find out how to go about changing those for a start and then see what else needs to be done.

Is there a widely-available source of (good) repair information for this car that is reasonably-priced?

Thanks again for all the help, I'm already beginning to learn a lot about this car,
AG

[aklim]

There is WIS. Werkstation INformation System. I got a copy on ebay

[michakaveli]

Originally Posted by aklim

Any codes? Could it be the MAF? Maybe try cleaning that with a shot of Electric Cleaner?

What about the fuel lines? Are they leaking?

There is no MAF on the NA OM606

[Matt L]

Originally Posted by michakaveli

There is no MAF on the NA OM606

Thus my comment that the computer doesn't monitor much. Note that this statement still applies to the turbo model (at least when compared to a typical gasoline engine), but the turbo 606 does use a MAF.

From what I can glean, with the early 606 anyway, the rack position follows the pedal (with the cruise off, of course), except on overrun where the fuel supply is interrupted to enhance engine braking.

[nhdoc]

Originally Posted by AGx

Those lines are somewhat yellowed (brown) so I wasn't able to tell if they were full of fuel or air and the car was in a spot where I couldn't get it pointed downgrade - as luck would have it, it was oriented uphill. Anyway, I put two 5-gallon cans of diesel in the tank raising the fuel level to almost 3/4 tank and after cranking for about 15 seconds, the engine started idling very raggedly and then smoothed out.

As a result, it really seems to me that an air leak into one of those clear plastic lines it the most likely culprit at this point since the car runs normally once started. I'm going to try to find out how to go about changing those for a start and then see what else needs to be done.

Is there a widely-available source of (good) repair information for this car that is reasonably-priced?

Thanks again for all the help, I'm already beginning to learn a lot about this car,
AG

It's almost certainly a leak in the fuel lines allowing the fuel to run back to the tank that's the cause of your trouble. The fix is not difficult, involved replacing the lines and the o-ring at the shutoff valve while you are at it. The entire set of parts is about $100 and should take you 3 hours or so as a DIY project. There's plenty of information here on that, just do a search for it and you'll find it.

[AGx]

I think you're right about the leak, twice yesterday I could smell a slight odor of diesel when walking past the front of the car in this very hot/humid weather we're having here - 95 degrees, 85+ pct humidity. Funny thing is, I still haven't actually seen a sign of leaking fuel yet, but if its just enough to let some air in maybe that isn't so strange. I missed the dealer's parts dept. twice now thanks to that job of mine, but should catch them in the AM to pick-up/order those fuel lines and the shutoff valve o-ring for starters. I'm hoping that I can change all these parts w/o the need to remove the intake manifold, but based on the posts I've seen here, that's probably wishful thinking - tho maybe my NA (non turbo) engine has better accessibility.

Thanks again for all the help, I'll post a status report when I get those parts installed.

AG

[nhdoc]

You won't see a puddle under the car in most cases because there's a belly pan which catches all the leaking fluids and disperses them once you start to drive off...it's a blessing and a curse in that is saves your driveway from staining in most cases but you don't realize you have a leak until it is pretty severe.

That, plus the leak which prevents the car from starting is usually an air leak that allows the fuel to run back to the tank, especially when the level is low, so you might not even see any fuel leaking then anyway...but chances are if one seal is leaking that several are...just replace them all and your car will be good to go another 6-7 years.

[TMAllison]

AGx

On my 99 turbo you can unbolt, disconnect electrical lead, and flip the windsheild washer bottle out of the way and get room to work. I think yours would be pretty much the same layout on that side of the engine.