91 300e problems because of the rain? - PeachParts Mercedes-Benz Forum

mbzr4ever · #1 07-22-2007, 04:25 PM

Don't laugh, this is what my mercedes mechanic told me.

OK, so the 300e ran perfectly about 4 days ago. Then I decided to use the 240D for a few days, and the 300e sat. Meanwhile it has rained a lot.

Yesterday, I took the 300e to run some errands. Everything normal for about the first 5 miles. Then, at a stop light it started to stall out. Sounded like it wasn't getting fuel, stumbling. Gave it some gas in neutral to keep it from stalling out. Made it to the post office, where I shut off the engine. Came back out a few minutes later, would not start. It cranked, but would not turn over. Tried a number of times, then thought I'd better quit, might run the battery down.

So I decide to walk to the gym ( few blocks away), do my exercises, then see if it starts later. And, of course, it is still raining. Who do I see on my way over? My Mercedes mechanic, he was passing by. Asked me why I was walking, I told him about the car that was stuck at the post office. He said, maybe something is wet, to call AAA, then drove off. Yup, that was the help I got.

After a hour and a half at the gym, I walk back to the post office, and started the car. No problem. Drove the car straight home. Looked under the hood, and the only thing I noticed was a hose that connects from the air filter to the top of where the cylinders are (don't know the name) was slightly disconnected from the hose rotting.

Could this have caused the problem? I had this (if not a similar problem) a few years back, and it was because the distributor cap was loose. Don't know the exact details, have to find the receipt. But I don't even know where to find the distibutor, could someone point out where it might be?

And I thought of pouring some SEA FOAM down the carburetor, took the air filter off, no carburetor. Just a flap that, when pushed, the engine died. HELP, need some guidance here...

Could it be from the rain, and something electrical be getting wet? If that is the case, mercedes makes one heck of a (BLEEP) car, and I find that very hard to believe! (This coming from a diesel believer).

brewtoo · #2 07-22-2007, 11:55 PM

My '90 124 behaved that way. It turned out to be the coil. YMMV.

G-Benz · #3 07-23-2007, 06:32 AM

My VW behaved like that years ago during moist conditions...corrosion in the coil was the culprit.

I agree with brewtoo...it's the coil...

Arthur Dalton · #4 07-23-2007, 06:54 AM

Next time it happens, spray the wires with WD40 and retry to start..if it starts , change the plug/ignition wires.

mbzr4ever · #5 07-23-2007, 10:42 AM

Can someone please point me to the area where this coil might be found?

yal · #6 07-23-2007, 11:10 AM

Follow the spark plug wires from the engine to the distributer. There are six wires. When you get to the distributer you will see a 7th wire, follow that wire from the distributer to the coil.

mbzr4ever · #7 07-23-2007, 03:52 PM

Quote:

Originally Posted by yal

Follow the spark plug wires from the engine to the distributer. There are six wires. When you get to the distributer you will see a 7th wire, follow that wire from the distributer to the coil.

aah, no wonder I could not find the distributor. Hidden under a nice little cover to keep everything clean. OK, followed the 7th wire to another black plastic cover (sorta triangle-shaped), I'm assuming it is the coil. Does this plastic cover just pop off, twist or pry off - don't want to break anything forcing it off.

OK, so I'm looking at about $85 - $95 plus shipping for a replacement coil. Is this an easy replacement?

mbzr4ever · #8 07-23-2007, 03:56 PM

Quote:

Originally Posted by Arthur Dalton

Next time it happens, spray the wires with WD40 and retry to start..if it starts , change the plug/ignition wires.

In changing these, is it as easy as just unplugging both ends and plugging the new ignition wires back on? Looking at a replacement set of these ignition wires ($105 - $155 plus shipping), it's feasible, especially if there is not fancy install involved.

Arthur Dalton · #9 07-23-2007, 04:05 PM

Quote:

Originally Posted by mbzr4ever

In changing these, is it as easy as just unplugging both ends and plugging the new ignition wires back on?

That's all there is to it.
The reason for the WD trick is b/c WD is Hygroscopic [ absorbs moisture]
So, if the wires/connectors are wet and it then starts with a coating of WD, you have found your problem
It might also be a good idea to just take each wire off and squirt each end connector and put them all back on, [ including the coil one].
I also do inside the dist. cap. They get wet just from condensate formed from differing temps/humidity.
This usually does the trick if they are not real bad , but if re-occurance condition exist, just replace them
Plug wires are a maintanence item, just like plugs are ..so , your complaint of Benz poor quality on 15 years old wires is a joke.
...tell that one to the Techs down at the Benz Garage and they will laugh you out of the place.

Arthur Dalton · #10 07-23-2007, 04:24 PM

The more you read on this Forum , the more you will find stuff you can do yourself...Some of this stuff is "Mechanics 101" and can be understood by most anyone.
..and the advice here is FREE..maybe not always correct, but preety good as far as I see.
We have a built-in error correction factor here that you won't get from your Guy..
If one of us gives you bunko advice , someone else is more than happy to correct that post...usually with glee...

mbzr4ever · #11 07-23-2007, 04:33 PM

Quote:

Originally Posted by Arthur Dalton

The more you read on this Forum , the more you will find stuff you can do yourself...Some of this stuff is "Mechanics 101" and can be understood by most anyone.
..and the advice here is FREE..maybe not always correct, but preety good as far as I see.
We have a built-in error correction factor here that you won't get from your Guy..
If one of us gives you bunko advice , someone else is more than happy to correct that post...usually with glee...

Thanks very much for the help...BTW, I noticed some hairline cracks in the distributor (cap?) where the two screws attach. I'm guessing some condensation might be able to get in this way?

Right now, we're blessed with some sunshine (for a few hours?), and I have the hood up, hoping to dry out anything that is wet.

Arthur Dalton · #12 07-23-2007, 04:37 PM

Quote:

Originally Posted by mbzr4ever

Thanks very much for the help...BTW, I noticed some hairline cracks in the distributor (cap?) - what the ignition wires are plugging into, under the cover. I'm guess some condensation might be able to get in this way?

If there is any evidence of hairline cracks on a dist cap, just change it right off...Electricity follows the cracks as they also hold the moisture, so that could well be your problem. Caps are not air-tight anyway.
Change cap and spray all wires/connectors and try it out. If any re-occurance, then I would go for the wires.

mbzr4ever · #13 08-05-2007, 09:37 PM

There seem to 3 distributor covers/caps, which one gets replaced?

One black smooth cover on top of everything (I assume this does not do much for any moisture), looks more like for cosmetic/organization purposes.

The black cover with holes for the wires (this has hairline cracks on mine, but I doubt this would be the cause of the problem?)

Another distributor cover, underneath, but red colored. I would think this is the part that needs to be waterproof, as it has a gasket. I did not remove the black part to uncover this, so I can't readily determine its condition.

In the meantime, I'm finding if I run the car everyday (yes, it's still raining everyday) for at least 15 minutes or so (evaporates the moisture?), I have no problems. But if I let it sit for a day or two w/o running it, it will stall out within 10 minutes.

crhenkel · #14 08-06-2007, 01:37 AM

The black cover over the distributor cap is usually included on the new cap already, at least with Bosch parts it always has been. I was told it is an extra measure to reduce electrical interference, like a shield. It should be replaced and kept installed on the car, it probably is with the new cap. Get a cap, a rotor, and some new wires, wires are definietly a maintenance items and should be replaced about every 4-6 years minimum in my expereience if you want the engine to run its best. Some people do it more often! Definitely if they are over 10 years old. The proper resistance in the wires breaks down. A new coil cant hurt either. Any and all are super easy to replace yourself. Good luck and ask questions, its what it is here for.

mbzr4ever · #15 08-06-2007, 11:51 PM

Thanks for the reply, crhenkel. I forget sometimes this gas car requires more maintenance than the diesel, but these changes seem simple enough and not too expensive, I'll change the 3 parts, like you suggest.