After a joyful winter of perfect starting, idling and running, last Friday, my 89 300se has begun stalling as I slow down to stop. While still rolling I can put it in neutral and it will start instantly and drive normally. The next time I slow down it may or may not stall again. Most times it settles into a normal idle but maybe 1 out of 3 times the rpms drop to zero and it stalls.

Last spring and summer I went through a long process of trying to resolve a start-stall-start-stall-start-chug-chug, run problem. With the help of this forum I finally resolved it by installing:

• New Injectors
• Replacement (used) OVP
• New Fuel Pump relay
• New O2 Sensor

Along the way I also replaced all the following parts:

• Ignition Coil
• Distributor Cap
• Rotor
• Ignition Wires
• Spark Plugs
• Crank Position Sensor
• Spark plugs
• Fuel pump
• Fuel filter
• Fuel accumulator
• Hoses leading to and from the ICV
• All fuses
• Air filter
• Coolant Temp Sensor
• Throttle Position Microswitch

• Can anyone give a clue as to what may have gone wrong.

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2000 Mercedes S500
1990 Mercedes 560SEL
1970 Triumph Spitfire

What about the coil? Has it ever been replaced?

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Fred Hoelzle

Longshot - I believe there's a decel switch in the linkage, maybe corrosion or a bad switch?

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Closing the store
Benzbonz.biz on your smart phone or tablet.

Never buy used OVP's. Replace it with a new one first of all before you do anything else!

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2016 Monsoon Gray Audi Allroad - 21k
2008 Black Mercedes E350 4Matic Sport - 131k
2014 Jeep Wranger Unlimited Sahara - 62k
2003 Gray Mercedes ML350 - 122k

I wondered about this. I had put it in during the the long search for the solution to my start-stall-start-stall-start-chug-chug-run saga but it didn't make any difference. I just left it in place.

When the stalling started the other day, I put the original one back in, but the stalling continues about 1 out of 3 times I'm coming to a stop.

One thing I forgot to mention is that the day before the stalling began, I jump started my wife's Chrysler convertible with the car. Her car hadn't been used in many weeks and the battery was so totally dead that 48 hours on my battery charger wouldn't put anything in it. It started OK with a jump from my MB but wouldn't stay running until I got it up to opereating temperature, probably 10-15 minutes, so the two cars were connected for a lot longer than you would want in a normal jump start.

Could this have anything to do with the failure of the OVP or something else?

Oh, the coil was replaced with new early in the process of the original problem. I'm ordering a new OVP today. I'll report if it does the trick.

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2000 Mercedes S500
1990 Mercedes 560SEL
1970 Triumph Spitfire

Absolutely. I had stalling at lights on my 300TE when I got it. The PO complained it was the problem. I registered on this forum and was instantly told to replace it. I did and problem has not returned in 4 years.

Buy new and I bet it'll solve the problem. The OVP is not an issue of if, it is when.

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2016 Monsoon Gray Audi Allroad - 21k
2008 Black Mercedes E350 4Matic Sport - 131k
2014 Jeep Wranger Unlimited Sahara - 62k
2003 Gray Mercedes ML350 - 122k

OVP and fuel relay ,stalling cause components in a 103 engine,

mak

300se

I replaced the fuel pump relay with new last summer, a new OVP is on the way. Should be here Friday.

'Course when I drove the car yesterday, it ran perfectly, never stalling a single time.

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2000 Mercedes S500
1990 Mercedes 560SEL
1970 Triumph Spitfire

after that list of parts I can only think bad Karma.....something is telling you you shouldn't own this particular car....just a thought

and the fact of the matter is these cars are not that unreliable...they call it a Mercedes for a reason....you guys are monkeys aren't you...you don't really know what you are doing here do you? There is NO WAY you could install ALL of the parts yourself mentioned above and have these results? No, that's impossible...stop with the bull****ting..it's obvious

Well . . . yes I probably am a monkey or at least a monkey's uncle. But I did replace all those parts myself. My biggest mistake was the order in which I replaced them. If I'd done the injectors first I probably wouldn't have had to do the rest. I just consoled myself that since I bought the car without a scrap of records, at least I now have some. And, no I don't know what I'm doing, and without the support of this forum I would have given up on MB ownership a long time ago. You are right, though, with proper maintanence they are not unreliable. They only seem that way when they've been abused and/or neglected.

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2000 Mercedes S500
1990 Mercedes 560SEL
1970 Triumph Spitfire

The new OVP arrived yesterday, but the stalling persists. It's weird really. The car runs and idles perfectly most of the time. But every so often it stalls when I slow down to stop. I drove it about 50 miles last night and it did it once. Drove 25 miles today and again it did it once.

How likely is that my "less than 6 months old" fuel pump relay is the culprit?

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2000 Mercedes S500
1990 Mercedes 560SEL
1970 Triumph Spitfire

ok, what is an "OVP". just bought a 89 300se for 900 dollers. whatever problem you guys are discossing at any given time, i have that problem. BUT. it runs. i replaced alot of those parts you mentioned, plugs, wires,cap,rotor, various vacuum seals. ok, mabey some of the parts you did. i have a rough idle, heater blower blows ALL the time on high. NO heat, and high rpm at crusing speed (3500 at 70). i might be rambling a bit im just so damn happy to talk to someone that has a love/hate with their MB like i do. any way, did you check what your vacuum is at idle AND\OR is you timing chain keeper tight. thinking at decel the chain slackes off enough to throw timing off and killing your precious. first post ever. too wordy?

. first post ever. too wordy?[/QUOTE] NO

welcome . you will progressively learn all about the weak points of the 300SE and be able to rectify them .
Do check mail for spelling. makes reading so much easier to ..
mak
300sel

Bolomiester, when you say "Coolant Temp Sensor", do you mean the sensor near the fire wall, the last one on the top of the engine? The one near the fire wall has a 4 pin connector and controls the idle when the car is cold. If bad could send the wrong signal to the computer and lower the RPM, but is not likely that this is your problem.

The OVP/fuel pump relay is usually the cause for these problems, but since you changed it, you may want to check the socket/plug connections for corrosion or bad connections within the socket. The fact that your problem happens from time to time, makes it difficult to diagnose. I had the same problem, where the RPM would drop almost to 0 for some time. Three days ago the RPM dropped while I had the hood open, so as soon as I touched the OVP the RPM went back to normal. I changed the OVP with an other used one I had around and the problem didn't happen anymore. Keep in mine that I haven't been driving the car much but if it happens again I know to check the connections in the socket.

Good luck
Michael

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1990 300E 264,000 miles
1992 300TE 188,000 miles