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91 300e problems because of the rain?
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). |
My '90 124 behaved that way. It turned out to be the coil. YMMV.
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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... |
Next time it happens, spray the wires with WD40 and retry to start..if it starts , change the plug/ignition wires.
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Can someone please point me to the area where this coil might be found?
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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.
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OK, so I'm looking at about $85 - $95 plus shipping for a replacement coil. Is this an easy replacement? |
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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. |
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...:):) |
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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. |
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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. |
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. |
black distributor cap cover
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.
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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.
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Keeping moisture out of the distributor cap.
My '86 300E has not given mr trouble from moisture in the distributor cap but several other cars of mine have done so. In all cases, the car would start, I'd drive a short distance, stop the car, and then have trouble restarting it. I believe that the moisture inside of the cap would evaporate from engine heat, then condense on the top of the cap near the spark wire terminals. This then shorted out the spark path. :eek:
I was able to eliminate this problem by smearing silicone grease around the edge of the distributor cap where it bolts to the engine. I also removed each spark wire on the cap and put silicone grease on the inside of the rubber boot to seal out moisture. I did the same at the coil as well. :) I have found a big increase in electrical reliability by using that silicone grease on all electrical connections. In fact, there was a TSB in abour '93 or '94 from Volvo telling their dealers to do this whenever a car was brought in for any service. This is a good way to prevent problems with those fuses in the older MBs too. Same fuses in the older Volvos were a problem. :D I but a large tube of 'SylGlide' brand silicone grease and use it on everything but my morning toast. :dizzy2: |
now surely the only reason that you don't use it on the morning toast is that you don't want to have to go buy more?
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Am I so obvious?
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Actually, the flavor is pretty blah. Now if they come out with a strawberry flavored Sylglide.........hmmmm. :idea3: |
dielectric grease
It is a good idea to use a good dielectric ( non electrical current conducting) grease on the boots of the wires, the sealing edge of the cap, and sometimes even on the ceramic portion of the spark plugs when you are having spark and electrical current issues. One- it makes the wires easier to pull off when needed. Two: it helps to keep the electricity from following the path of least resistance and seeking a ground other than the route the electricity is supposed to take.
An old trick on old poorly shielded spark wires on muscle cars was to take a lead pencil and make a heavy pencil mark all along the ceramic portion of the spark plug, from the electrical tip to the engine block. If you got the lines heavy enough and just right, you would cause the electtrical current to follow the pencil line to the engine block instead of the spark plug tip, or at least degrade the power of the spark. It would cause a dead cylinder or poorly running engine and your buddy or not so much a buddy would look forever to find the problem. Sometimes this is basically what can happen with bad wires, cap, rotor, or plugs. Tiny breaks in plastic, carbon tracking, degraded wire sheathing, etc can let some or all the electrical current travel to where it shouldnt or ground out, with or without moisture, depending on the damage. Also, sometimes, wires break down internally and only leak voltage or ground out after they heat up. Fine when cold, but after getting hot the wires can cut out, ground out, or short and cause misses, bad or no acceleration, or stalling due to the drop in resitance. Always consider changing old spark plug wires. The high cost of the wires is nothing compared to the benefit good wires give your engine. Good luck |
300holst (or anyone),
Where did you find the SylGlide? Did you buy it online? |
OK, found it at napa.
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So if the dielectric grease in non conducting it should be used on the outer portions as a stop barrier & moisture barrier. I was reading someone put in on the ends on the fuses & contacts evidently this would inpede conduction therby making contact harder... So do I rightfully conclude that you should not do that? Thanks |
Silcone grease OK on fuses and electrical contacts (mostly)
The purpose of putting silicone grease on the end caps of fuses and on the pins of electrical connectors is to prevent air and moisture from corroding the metal contact surfaces. The grease doesn't prevent electrical contact because the grease is wiped off of the metal surface at the point of contact. The grease which was wiped from the point of contact just piles up next to the contact and acts as a further barrier to air and moisture. The normal 12 volt power in the car is well able to conduct through what little grease is left on the metal when the connection is made. :pleased:
The only exception I know of is the connector for the Oxygen sensor. The output of the sensor varies but is less than 1 volt always. It is not recommended to put any grease on this connector. Volvo came out with a TSB in about 1994 directing dealers to grease all electrical connectors EXCEPT that oxygen sensor connector. :sultan: |
OK, got my parts...
The new plugs, wires, rotor, cap and various other pieces just arrived today, thanks to Phil's exceptional service.
I also just bought the right size spark plug socket. What would be the recommended order of installation? I was going to do plugs, rotor/cap, then wires. Is this ok, or is there a better sequence of replacing these parts? At what points do I use the slyglide? Thanks again for any input from those who have done this before... |
applying the Sylglide grease
The sequence you have figured out seems right to me. I would apply the Sylglide as follows:
1. To the gasket where the distributor cap seals. 2. inside the rubber boots where the wires connect to the distributor cap. 3. Inside the rubber boots at the spark plugs. Sometimes I install the plug, then grease the connector end and the white porcelain part, the push on the wire and boot. You don't need a lot of grease on the boots. I don't know if you are replacing the ignition coil but all rubber boots and electrical connectors at the coil should be opened and the silicone grease applied. On the connectors, I fill the female part with the grease so that the male part pushes the grease out when the connection is made. This effectively fills all voids and seals out air and moisture. |
300holst,
Thanks for the directions. Didn't order the coil yet, was going to see if these parts did the trick first. Before I start, I think I have all the supplies, but forgot to ask if there were any other special tools, besides the SP socket and gap measuring tool, that I might need (besides your general wrenches, etc)? The plugs say to torque to 15 lbs, which does not sound like much. What is that approximately after snug with the socket wrench? 1/4 turn? |
Here is a summary of what I did today:
Disconnected the battery. Tried to get the old spark plugs off and they were on too tight. I know my limitations, so I skipped this part and went on to the wires. Will get those changed later by a shop/mechanic. Changed all the ignition wires, using the sly-glide and put them in the new wire management piece that runs on top over the plugs. My only problem here was the coil wire was attached with 2 plastic clips that broke, they were so old. So I had nothing to attach my new wire to keep them out of the way. I used a small metal hose clamp to attach the coil wire to one of the clamps of the air filter housing, until I can figure out something else. I discovered the black suppressor housing was broken on the bottom, in fact, the bottom screw was very loose. This might account for the trouble I was having, we shall see. My old rotor was plastic and it was nice to see my one was metal, although I liked the old screws better, they did not strip as easily as the new ones. All in all, my new parts look very nice, it was almost a shame to use them, LOL! The new suppressor housing fit perfectly into the rotor cap, used some more sly-glide and everything screwed together to make a nice snug fit over the rotor. Then the cover snapped on, like it should. My old one had fallen off and melted on the engine! What a difference, it looked nice, anyway. Connected the battery, started it up, maybe started a bit faster than before, but that was the only difference I could tell right now. Not bad for a girl!!! The real test will be if I don't start it for a few days, especially if it has been raining, and see if it will start properly. |
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Good job! Hope it helps. |
brewtoo,
Thanks for the encouragement. Patience is key, LOL! In taking the boots off the plugs, I just twisted and turned the same time. What helped a lot is a pair of bent needle-nosed pliers. They were helpful in taking the boots off the distributor too, since it is kinda tight up front. I'm wondering if there is a special tool for taking off the "frozen" plugs? I even sprayed them with WD 40 and let it sit a while. Tried the first two, then decided I did not want to risk breaking the plugs. At least the car would still run, which I really need right now, since my 240D has another ignition issue. |
You're using a ratchet with a spark plug socket?
Maybe you need a longer ratchet if you can't turn it. As long as you keep the socket on the plug straight, it will not break. |
Hey mbzr4ever,
Please let us know how it's going. I have the identical problem as yours. Mine is a 1990 300E and it runs great but if I don't drive it for about 3 or more days in a row it starts and runs perfectly until it starts to warm up like about 10 minutes or like 5 or 10 kilometers later, it will then stumble and stall. After stalling it will not start, but it will start and run perfectly 1/2 hour or 1 hour later. It later never misfires or stalls at all, untill by chance I don't drive it for a few days again. Also in my case I noticed that the fuel pumps don't run when it wont start and I suspect that the OVP Relay is intermitently not supplying power to the MAS control unit which then fails to supply power to the fuel pumps. There is a lot of info on these potential culprits but testing and tracing the problem withought unecessarily (opps) replacing parts is key. I'm still in the testing/tracing stage with mine and I will let you know what I find. good luck and be carefull, Acky |
Acky,
How could you be so lucky as to have the same problem with your 300e? Mine has almost 170K miles, is yours about the same? Does it seem to matter if it rainy/humid? I hear you, these 300es are quite "sensitive" with all the electronics, which is why I prefer to drive my 240D as the daily driver. Every post, though, suggested getting new plugs, wires, rotor and coil, if necessary. I was even scolded in this post: http://www.peachparts.com/shopforum/1570884-post9.html to expect such replacements as necessary maintenance items. The wires I replaced were bosch, and I cannot tell if they are the original or not without going back through the many years of maintenance records. The wires, rotor/cap were all easy enough to change. But honestly, I don't notice much difference in how she sounds. Am planning to change the plugs by a mechanic on Friday (appointment is mainly for the front brakes). That's interesting about the fuel pumps - yes, when it is hard to start, it sounds as if it has run out of gas. Ok, keep in touch... |
Pretty good for a girl
You did better than me I whimped out after I did the rotor & cap I broke a vacumn valve after that I put it back together Figured I'd get help w the wires & plugs. Took me forever to get them off the cap finally did get them twisting turning w a pliers Needed a tool couldn't get enough strength from my fingers in the tight spot After I figured it out wires came off cap fine They have a boot puller for the wires at plugs thats good when you want to reuse I just figured I did enough damage& I couldn't see risking more for me to install wires that would have to come off to change plugs. Luckily the broken part was cheap easy fix & might have been defective anyway... Plugs can get tight esp if its a alum head & if they r installed wo anti seize. Alum head is softer than the plug metal so overtightening or mistreading can be damaging. No harm ever came from asking for help... :cool: |
CamelotShadow,
Did you change the rotor/cap (and wires/plugs) because it was just a maintenance item or were you having specific problems with your engine? I see you have the 500 SEC, so I'm assuming it was for this car? If it was for a problem, did this change take care of it? |
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only have 1 benz 1st & only benz thats it I had a hot hard restart prob was hoping maybe it would help but really did it for maint no real problems just wanting to make it better think idle smoothed or that could be vac hoses too. In fact mech saw cap & said its still good rotor was burnt a bit Its not humid here I have heard the plastic covers on top the dis cap can hold in mpisture & can be sources of problems not sure if you have that kind? It can't hurt to have new dis cap & rotor & igniiton wires plugs My mechaninc changed the aculmulator he thought thats why it was not starting hot He may have got it as it started today after sitting 40 minutes which ordinarlly would take alot of cranking :D |
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There is another black cover that goes over everything (wires/distributor) and someone (above) mentioned it was good to have to keep electrical interference away? I do know that my old suppressor and cap were loose on the bottom, easily allowing moisture into the rotor area. Glad to hear you have your problem fixed. You are lucky to have a good mechanic to help you along. |
Just went over some previous posts - is there supposed to be a gasket between the cap and the rotor?
There is still the coil that could be the culprit.....is that difficult to change? |
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Anyway, I'm taking the 300 in for the front brakes on Friday, I'm gonna ask the mechanic to change the plugs at the same time. He shouldn't charge me a lot, maybe 15 minutes, max? |
I don't know your car
but mine has no gasket I wish I used the dieletric grease as a seal myself on the rim of the dis cap Mine has no cap on top either I see the newer models have a cap over the wires To tell you the truth don't know how they do that as you got wires coming out all over it Someone told me that MB has discontinued that design it caused problems seems it doesn't stop moisture getting in but its good at keepin it in too. I don't know Its part of your design so you might want to ask around to see if it is aproblem They have extensions for the rachet need about a 4 or 5 on my car Let them do them & next time hopefully it will be easier to check them I hope my guys put dieletric grease in all the boots I hope thats standard protocol |
mbzr4ever, and all,
With my car humidity and/or outside temperature do not seem to be a factor because it has had the problem in winter or summer humid or not. Because I do drive the car regularly, it doesn't break down often. When it does stall out though it is a real pain and potentialy dangerous with cars scrambling and cutting each other off to get around. If your car is not fixed, and stalls out again, have someone turn the ignition on while you listen at the right rear wheel well. the fuel pumps are under the car just in front of the right rear wheel. Actually do this anytime so you will be familiar with the sound from the pumps. When the ignition is tuned on, the pumps will run for about 2 to 3 seconds then stop. If your fuel pumps do not run, there is a systematic test procedure to isolate the cause. Please do not replace pumps, relays, control units etc. Distributor caps, rotors, wires etc do wear and fail over time but they can be inspected and tested. (keep all good old parts as spares). Yes there is a large rubber "O" ring seal in the distributor area. I'll try to get a pic. My car has about 180 k kilometers. Please do not replace the coil just yet. Do you have a volt meter or multimeter? Take care all, Acky |
Acky,
Interesting, you say moisture does not seem to be a factor. Maybe I am associating this problem with the rain because it is now the rainy season when it first started acting up? Because I mentioned rain in the beginning, all subsequent posts/advice/recommendations were based on moisture entering the electrical system somehow... I used to drive the 300e every day, then I started driving the 240D instead, and sure enough, this is when the problem occurs, when the 300e is not driven DAILY. So now when I know I'm not taking the 300 out that day, I MUST run it (in park) about 15 minutes every day. If I don't, it has a terrible time starting (if at all) the next day. I agree with you about this being dangerous - what if I am in a busy intersection trying to make a left turn, and it stalls out? Good point about the fuel pump, will check into that. Yes, I do have a multi-meter. Gotta go and take the old wires/cap/rotor out of the trash, I threw them out, but like you say, maybe I should test them and keep as spares. Especially, when you live on a rock in the middle of the Pacific Ocean. |
Hi All,
I have the same stalling problem. It all started after I washed the engine bay.... It may or may not have been the sole cause, but it didn't have this problem before that, not even once. When the stalling started, it was almost present every trip out driving. any speed night or day. I got really worried and had the car checked out by a mec who did some extensive testing and still found nothing seriously wrong as far as he can tell. Oh yeah the usual " Your transmission isn't the best and ..." I drove off and got a Fuel Pump relay from the breakers. Its the only thing that is not expensive and easy to replace by me when it happens again. So I change it out. It has not happened again. I can't tell if that was the cause. But we could never know. All I know is that I do not want it to happen again. period. So now its ok. Given the choice again, I would still replace the relay. Anyway I keep all the old relays in the trunk for spares on the road. They are cheap from the breakers. Of course I don't keep a spare fuel distributor or Tranny.... hehe don't laugh. |
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You really live in HI? Lucky you I grow plumeria guess you know those weeds Sounds like maybe its sit related or jealous :D Do keep the old parts least take pics cap & rotor did they look burnt? then u could have wire or plug problems wires changed so now whats left. Its still happening? It may be more relay or fuel related than iignition relays can go slow first could be infrequent then getting worse n worse running it everyday seems excessive it should work with a few days or week sit My Volvo does & even more than that same w my old benz no problem even 10 days starts in a flash not so quick on restarts but I got a new accumulator & its better though not as good as cold start but still alot better than it was Stalling is a different thing could be a failing relay Had some hard starts then a few stalls in garage thern one on the road & I was lucky I got the car coasted safely to the curb wo hitting anything that was scary my tail end sticking out in the bike lane parked at an angle across someones driveway luckily the curbed stopped it just a few feet from a parked car Don't even want to imagine what would happen on the highway now you can;t even cold start after a day sit? sitting a day or so shouldn't matter By all means see what your mechanic thinks We can only guess Good Luck |
Everyone,
This sounds very important!! I was doing a google search on "300e stall" and this website came up: http://users.adelphia.net/~infoage1/complaints_nhtsa_mercedes_wiring_harness_failures_1991_1996.html MERCEDES-BENZ 1991-1996 ENGINE WIRING HARNESS DEFECT NHTSA COMPLAINT SUMMARIES (last update 04/18/2007 to 302 complaints) Apparently, this is a big problem that MB corporate refuses to recall. Something about the engine/fuel injection harness deteriorating, causing shorting, fire hazards, etc. Maybe everyone knows this already? Probably needs (or already has) its own thread. edit: here is the info: http://www.peachparts.com/shopforum/general-information/166883-wiring-harness-issue%3B-all.html |
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I believe this problem of desintegrating wire insulation does not apply to our cars W124 with 103.893 engines.
I think the problem exists in the W124 (some 1992 and all 93 to 95 models with 104 twin cam engines. Also some of the other model lines. It is always good practice though to inspect wiring and it's insulation when troubleshooting electrical problems. Please listen closely at the right rear wheel well while someone turns on the ignition. You will hear the pumps run (buzzing sound) for about two seconds). Next time if/when it stalls and wont start, listem for the pumps and you will recognize the sound, and know if the pumps are running or not. For your info in your spare time, test the old wires, distributor cap, and rotor this way; NOTE * if the any of these components are cracked, burned or otherwise broken, just replace them, they are garbage. The inside centre terminal in the cap is probably the first place to look as it tends to get wear,burn, and desintegrate. It is a protruding spring loaded terminal and should move in and out of the cap using your finger. Test the distributor cap With the meter set to measure OHM's (resistance) measure the resistance from each terminal one at a time with one probe in the centre of a terminal at the outside - and the other probe on the same terminal inside the cap. RESISTANCE SHOULD BE: 700 to 1300 OHM's Test the rotor at the middle (where is contacts the centre cap terminal) to the outer peak. RESISTANCE SHOULD BE: 700 to 1300 OHM's Test ignition cables (here it is not clear whether the spark plug connectors should be attached for the test or not, * I will double check) RESISTANCE SHOULD BE: 700 to 1300 OHM's I will get you the coil test procedure if you neet it. Good luck, Acky |
vegadonovan,
Hi, I suspect your problem is due to water geting into an electrical connection or component since you say the problem just started after you power-washed the engine. Having said that, problems and malfunctions can start to happen at any given time so it could be a coincidense (I know I have to learn how to spell). If you sprayed at or near sensors, electrical connectors, relays, etc. especially the EZL ignition module on the drivers side fender well, I suggest that you (with the ignition OFF) disconnect them and dry the terminals. I have noticed people with this problem at or near the exit of a local do-it-your-self car wash. I think anyone who MUST wash their engine cover up and stay away from these components. I used to regularly wash my 300D engine but never my E's Take care, hope this helps, Acky |
Just an update on the new plugs that were replaced yesterday:
Sounds like an improvement. Engine idles noticeably smoother, but not 100% perfect. So it was a good idea to change these. New brakes helped a lot, too, in making this car driveable again. So it appears we are thinking this is a fuel pump related problem....thanks, acky for your insight. |
You are very welcome mbzr4ever,
I have 2 files with info and instructions for you if/when your car stalls and wont start in future. Please e-mail me and I will attach in reply. Good luck, Acky |
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