Donna:
1. Go back to original spark plugs, Bosch H9DCO I believe it is, .032" gap. The problem with Platinum plugs is that they are typically resistor-type plugs. The plug wires on a MB have the resistors built into them, so you are running double the resistance in the plug wires, which is a bad thing. This could be the root cause of your driveability concern. The 3 mile trips don't help any, and I would still think the valve stem seals may be a concern, but again at this point may only be the cold-start "false start" problem.
2. A 91 300e has very little to offer in terms of on-board diagnosis. It won't pick up on the bad Overvoltage Protection Relay. Again, there is a TSB on/around this year. The OVP should be examined to check the part number and country of manufacture. If you want I can post the "bad" info for you.
3. Be aware if you use a battery cut-off switch, you will need to recode the radio to have any tunes while driving.
Gilly

Donna,

First thing first, change that Over Voltage Protection relay. It may not be the cure so keep the old one (you said you are on a budget ) and return the new one if it does not solve the problem (however they may not be return on electrical parts).

The hard starting could also be caused by the engine coolant temperature sensor. At cold start there has to be fuel enrichment since the fuel will condense on the cold cylinder walls. When this happens you will have hard time starting the car without the extra fuel added to the air going into the engine. The signal for enrichment is provided by the temperature sensor on the top of the cylinder head by the firewall. It is a sensor with a two-pole connector on top of it. All the tech has to do is measure its resistance to ground. If it is infinite there is your problem. Not an expensive part, around US $75.00 Parts Shop has it right here. And yes DO the right thing and drive the car at higher speeds couple of times a month. Don't floor it in city traffic, go on the highway and cruise at elevated speeds for a while. I usually do around 100 miles/hour for 5-10 minutes (well I go faster then that but it is up to you ). About the platinum plugs. I have been using them for at least 150,000 miles without any ill effects (not the same ones of course ) so if you are on a budget leave them. If not replace them.
Try to find a competent tech with Benz experience in your area (check out the Good Tech section in this forum) it will save you lots of money and headache on the long run. That car is fabulous and will last you a long time (I know I have one ) if you maintain it well. The way you are driving it qualifies as "severe" so follow maintenance schedule accordingly.
Change transmission (including torque converter) fluid and filter, engine coolant, power-steering fluid and filter, differential fluid according to the manual.
Good luck.

Alex

[Edited by dacia on 06-10-2001 at 01:24 AM]

I think the owner's manual is calling for disconnecting the battery before using a charger. That is to avoid burning the fuse for voltage overload protection.

David

Okay, everyone has beaten you to death about the OVP being the source of your problem, so I will add my two cents worth:

OVP!

No, a faulty OVP will not show up on the fault codes, and the intermittent failure will cause hard starting problems, stalling (especially with A/C on), ABS light coming on, etc.

I just replaced mine a couple of months ago (at the suggestion of this forum), and it solved problems similar to yours. (What a great forum!)

As far as everything else:

Definitely go back to copper plugs...my VW hated the platinum ones too, and I switched to copper Bosch plugs (must be a German car thing).

Just like trying to fire up the lawn mower after a long winter, unstabilized fuel in a vehicle will cause problems...had to rebuild carbs in my Bug after unintentionally storing it for five years!

Extremely short trips will do more damage to the engine than you can imagine...take a long route whenever possible to your destination.

Otherwise, it's a great car! Makes me proud to be able to work on it myself!

__________________
2009 ML350 (106K) - Family vehicle
2001 CLK430 Cabriolet (80K) - Wife's car
2005 BMW 645CI (138K) - My daily driver
2016 Mustang (32K) - Daughter's car

Oh yeah, I've got some Italian in me too, thanks to my Mom...I was born in Pisa too!

__________________
2009 ML350 (106K) - Family vehicle
2001 CLK430 Cabriolet (80K) - Wife's car
2005 BMW 645CI (138K) - My daily driver
2016 Mustang (32K) - Daughter's car

Thanks Giulio and others! FYI -- my ABS (and ASR) lights
on the dash are on constantly -- they do not go off at all -- they remain on from the time I start the car until I turn it off. Does this particular symptom now sound a bit less like a faulty OVR?

Also, can I get some clarification on the OVR? How can one test this part; a fuse has been mentioned...can contacts be cleaned on the OVP? I do not want to replace it until I am fairly sure it will help.

Finally, can anyone shed light on what I can do to make my door chimes work again. The car is eerily silent except for that buzzer. Is it fuse-related? If so, where? THANKS ALL! :-) :-) :-)

The buzzer is behind the dash. The instrument cluster has to come out. The part is not too expensive but, it takes some effort to replace it. If you can live without it, you will save some money. As far as the OVP, it could be a number of things wrong and if the problem is intermittent it may be difficult to test it. However, based on the symptoms alone, everything points towards the OVP (like everybody else is recommending). The only way you can be 100% sure is if you can take it to your mechanic for a definitive answer but, even then, if it is not a good mechanic, he may miss it. Whatever you do, DO NOT TAKE IT TO A MERCEDES DEALERSHIP, if you want to save money.
Good luck!

__________________
J.H.
'86 300E

ASR and ABS light stay on all the time...still a symptom of the OVP.

The OVP relay does contain a fuse on the top. It is covered by a clear plastic cover. Check to see if it's OK.

I have heard of some members who have opened up the OVP and resoldered the poor connections and successfully repaired it...I'm kinda sloppy in that regard so I just bought the part and replaced it. I don't know about FastLane and PartsShop, but I got mine from Performance Products, and they had a money back, no questions asked policy on ALL parts, mechanical or electrical (very important when buying a $265 air flow meter and having it not solve a problem).

As far as your door chime problem, the chime unit may itself be gone (don't know where to begin on this one, since I don't have any experience here). Fuses are prone to age, and even though they make look good, they may have actually deteriorated. You may try replacing them systematically. Also, since several components share a single fuse, you mignt check the fuse chart and see if the components on the same fuse are working properly.

__________________
2009 ML350 (106K) - Family vehicle
2001 CLK430 Cabriolet (80K) - Wife's car
2005 BMW 645CI (138K) - My daily driver
2016 Mustang (32K) - Daughter's car

I suggest that you try the following after disconnecting the battery:
1. Replace the fuse on the OVP relay, it should right on the top, it may be blown, or just bad contacts. You may not have to replace the relay.
2. Use Bosch Copper Spark Plugs and not platinum, they do not work well in smooth idle or acceleration.
3. If you can find BG-44K Fuel additive, it is similar to Techron but is triple the potency. You can only buy at some GM or BMW dealerships. You add it yo your tank and then fill it up with premium 93, so that it mixes well.
Hope this helps.

Haven't read all of your posts yet Donna But your symptoms sound similar to my experience during the first month with my preowned 84 190E. It was the idle speed air valve(may also be called auxiliary air device). A cold engine requires a little more fuel and air so this air valve must be opened.

could the alternator not be generating enough to charge the battery? a serious drop in voltage lights up the asr/abs lights, at least it did on my 300e.