Engine shuts down while I was driving: M103 - PeachParts Mercedes-Benz Forum

Ron in SC · #1 05-01-2006, 05:30 PM

While I was turning a corner my engine suddenly shuts off, all dash lights go on. I turn into a parking lot and coast into a parking space. I put car in park and turn key. It starts with not troulbe and runs fine.

I wonder why it shut down. Fuel tank is full and battery has charge and alternator is charging system. Vehicle is a 1992 300TE with about 138K miles.

What might have caused this situation to occur?

derryb · #2 05-01-2006, 05:39 PM

Possibly a fuel pump relay going out. Do a search, all kinds of info on this site. Relay problem can be intermitant, gradually getting worse.

Ron in SC · #3 05-01-2006, 05:51 PM

When I test drove it again I did several sudden stops and one of the times the rpm dropped significantly lower than they did the other times. They dropped well below 500 rpm but the engine did not die. The other times they never dropped but 500 rpm. I'm thinking maybe a fuel/air mixture issue?

Also I have the A/C compressor running it that might make any difference.

Mike Murrell · #4 05-01-2006, 06:54 PM

I experienced the same situation early last summer. My MB also has a 103 motor.

Turned out to be the infamous OVP.

I removed it and while holding the flap shut, shook it. I heard rattling, indicative of an worn out unit. Replaced it and problem has not reoccurred.

I also lost a fuel pump relay(a few months earlier). When this happened, car would not restart until I jumpered pins 1 & 2 in the MAS unit. Your car may or may not have a MAS. I hope it doesn't -> $500.00 @ dealer.

What you've described sounds more like an OVP issue to me.

My 2 cents.

Ron in SC · #5 05-01-2006, 07:07 PM

Mike,
I have an extra MAS relay. Since I have two 1992 300Es I bought one, as a spare, for about $30 on ebay several months ago.

I'll check the OVP as you described.

loubapache · #6 05-01-2006, 07:27 PM

Quote:

Originally Posted by Ron in SC

When I test drove it again I did several sudden stops and one of the times the rpm dropped significantly lower than they did the other times. They dropped well below 500 rpm but the engine did not die. The other times they never dropped but 500 rpm. I'm thinking maybe a fuel/air mixture issue?

Also I have the A/C compressor running it that might make any difference.

Had the exact problems in my 1991 300E. Checked the OVP and fuel pump relay and all are OK. Changed the spark plugs and still no difference. Finally found the problem and it was the distributor cap and rotor. The contacts on the cap were so corroded that they just disintegrated when touched with a screw driver. If you have not replaced the cap and rotor in all these 100,000 plus miles, they need to be replaced. Mines were shot at around 100,000 miles.

Ron in SC · #7 05-01-2006, 08:21 PM

Quote:

If you have not replaced the cap and rotor in all these 100,000 plus miles, they need to be replaced.

I replaced them when I got the car a few months ago, so that would not be the problem.

86560SEL · #8 05-01-2006, 10:41 PM

Forgive my ignorance, but what is an OVP?

I am having similar symptoms with my 85' 380SE, perhaps the same issue? On my first trip out of the day it is fine. Typically it is my 3rd trip out for the day when it stalls out at a stop, or a slow turn. It always starts right back up. It is getting frustrating.

JBoggs · #9 05-03-2006, 05:03 PM

Check you battery connections. I have a cable that works loose on occasion and it acts as you describe. Since it was loose but still touching, dash lights would still operate but not enough juice to run the motor.

JB

Benz300 · #10 05-04-2006, 11:27 AM

on my 260E the car would shut off after running for half hour annd then would not start again untill the engine was cold again.
turned out it was the crank shaft position sensor ! very weird but then again mercedes issues are never ordinary !

89-300ce · #11 05-04-2006, 05:32 PM

In my case it was the fuel pump relay. It progressively kept requiring more and more time to cool off before a re-start.

Jorg

Ron in SC · #12 05-05-2006, 12:05 PM

I think my problem was the throttle micro switch. When I removed air filter housing I observed that the electrical connector to the switch was almost completely unplugged, i.e., half of the plug was in and half was out.

Problem has not reoccurred so that may have been the problem.

OTTOBUN · #13 05-23-2006, 02:59 PM

Quote:

Originally Posted by 89-300ce

In my case it was the fuel pump relay. It progressively kept requiring more and more time to cool off before a re-start.

Jorg

Where exactly is it located? I have a similar issue...

JBoggs · #14 05-23-2006, 04:16 PM

behind a small compartment door in the gloveobox, not sure where yours would be.

JB

89-300ce · #15 05-24-2006, 10:13 AM

Quote:

Originally Posted by OTTOBUN

Where exactly is it located? I have a similar issue...

On my 89 w124 it is between the battery and the passenger firewall behind a plastic splash shield, access from battery side. It is in the general vicinity of the OVP relay. To see if it is indeed a fuel pump relay test it when a stall has occured and it won't re-start. Have someone turn the ignition on while you listen for the fuel pump at the rear passenger wheel. You should be able to faintly hear the fuel pump humming for a few seconds after the igniton is turned on. In any case, a spare fuel relay kept in the trunk for emergencies is good policy.

Jorg