car died at light, ALL warning lights came on, no start - PeachParts Mercedes-Benz Forum

#1 12-07-2002, 01:50 PM

Last night at a very inconvienent time of 12:30am (well, I guess it was today), after the car had been running for about 5 minutes, I was braking to stop at a light and all of a sudden, ALL of the warning lights went on and RPMs went to zero. No warning, no odd sounds, no funny performance. When I came to a full stop, I shut off the car, and tried to restart it. I got plenty of electrical power, meaning the lights don't dim when I try to start it, all the lights came on and the radio worked. The engine tried to turn over, but it didn't start. So.... I pushed the car while someone else steered (what a heavy f*&king car!!). Once we got it into a parking lot, I tried to restart it. Same thing, all the warning lights come on, engine cranks, but does not turn over. The warning lights even come on with the key turned to the accessories position without trying to start it.

A few weeks ago I had a similar problem where the car wouldn't start. Did not have a problem with the warning lights coming on. I had the relay, filter and pumps replaced. After that, my car ran great. Then, I started to have a problem with the RPMs dropping once the engine turned over. With the car in Park, the RPMs would fall down to 5 or so, then jump up to 10. Once I shifted into drive or reverse, the RPMs would come down to 7ish. It would run slightly rough until the car warmed up (just a touch under 80 degrees) and then it ran perfectly. Most times when starting, I had to give it a little gas because it seemed like the car was going to stall out.

The exhaust seems to have a bit a gas smell to it. It was like this before and after the relay and pumps were replaced.

When it starts (this is after the new fuel pump etc.) I hear some kind of thump sound. From the driver's side, it seems like it's coming from some where on the right side.

Mileage wise, I get about 300miles/tank.

Not sure if this matters, but I have a kill switch installed whereby one has to have the left turn signal on for the car to start.

Based on what I've come up with from reading this site, it seems it could be one of these problems:
- relay
- pump
- 02 sensor
- I suppose, I could have just run out of gas, but the guage was indicating a bit less than half full after driving close to 200 miles.

86 420SEL w/aprox 130K miles

Here's the link for comments about the problem the first time it happened.

http://www.peachparts.com/shopforum/showthread.php?threadid=49415

#2 12-07-2002, 06:36 PM

I went back to the car today around 4:30 where I was forced to leave it this morning.

Tried starting it, but to no avail. I did make it a point to have my friend that drove me start the car while I'll sat outside by the gas tank. Once he stop turning the key and the engine stopped trying to turn over, I could a subtle whirring sound from area of the gas tank. I would assume that it was the fuel pumps working.

I tried to pull out the relay to take a look at, but could not easily get it out. I didn't even want to try and force it? Is there a trick to removing it?

Also, just to the right of the relay (as you stand at the front at look at the windshield) there was another fuse about 1 inch square and a few inches tall with a red top. What is that?

Inside the fuse box on the driver's side, there are other "things" in there besides fuses. What are they.

No noticable smell of gas coming from the engine when I try to start it.

David

Behind the Star · #3 12-07-2002, 10:26 PM

The one inch square part with the red top is the overvoltage protection relay

Do you have spark?

Brian

#4 12-08-2002, 12:48 PM

I would assume I have a good spark, though I haven't checked. The car was running FINE up to the moment it died.

Seems the OVP relay could also be a source of problems, based on what I've read from searches of this site. Is this true?

I wanted to check the fuse in the OVP but I must be doing something wrong because I feel like I can't pop the top on it.

#5 12-08-2002, 01:45 PM

Seems to be a problem with the fuel pump relay. Turn on the ignition and try to hear the feeble buzz of the fuel pump starting up. The sound should be heard from the rear right side. If not you sure have a relay problem.

#6 12-08-2002, 02:58 PM

Hi David,

Check the Fuel pump relay before you go ahead with any diagnosis.

#7 12-08-2002, 06:02 PM

I turned the key without starting and heard the buzz of the pumps kick in.

I tried to check the relay, but couldn't get the darn thing out and I was pulling pretty hard. Is there a trick to this?

Fuse in OVP relay is good.

Keep in mind that the relay, pump and filter were all replaced on November 8 by Raul at Ultimate Euro Repairs in Davie, FL (based on posting on this site he's supposed to be good).

The relay looks brand spanking new, is there a way to check to make sure that the pumps were actually replaced. Are they the two silver cylinders side by side underneath the gas cap area on the bottom of the car? Whatever those things are, they look brand new.

#8 12-09-2002, 06:55 PM

I dropped my car off at Ultimate Sunday evening. They were closed so I dropped my key in the drop box. Monday morning when I called at 9:30am, Raul (the owner) picked up and had already fixed the car. Bad ignition coil.

Total cost (parts/labor/tax) =$240.

Starts right up and has no rough idle either.

By the way, I highly recommend this place to anyone that is in the South Florida area. Seems like a great shop. Raul is really nice. Prices seem fair. There must have been 20 older model Mercedes at his garage when I picked my car up this afternoon.

Behind the Star · #9 12-10-2002, 07:36 AM

So what was the problem?

#10 12-10-2002, 06:13 PM

raul, the mechanic, said the ignition coil just failed, i.e. stop working all of a sudden.

does this seem plausible?

car runs great now.

Behind the Star · #11 12-11-2002, 07:42 AM

Thats normally how it happens.

Brian