Mercedes/420SEL Engine Suddenly Dies
Advertisement
Question
I have an intermittent electrical problem with my 1988 Mercedes 420sel. Car has approximately 130,000 miles on.
I recently started having an intermittent problem of the car suddenly stalling. You will be driving along, or stopped at a light, and suddenly, it's as if somebody flicked a switch, the car engine will stop. There is no pre-warning such as faltering rpms or stumbling. Car will start immediately afterwards after about 5-10 seconds of cranking. Normally the car starts with 1-2 seconds of cranking. It tends to happen intermittently and when it does it doesn't reappear that day.
The few times it happened the car was fully warmed up.
Apart from this issue the car runs fine. Idle is generally smooth though on occasions there is a slight lumpy feel which goes away if you give a squirt of gas.
Acceleration is smooth with no hesitation.
I've noticed no other problems with electrical system or with engine.
I've been checking the Mercedes forums for answers and the two most plausible answers seem to be either the fuel pump relay or the overload protection relay.
I'm wondering if you can give me your opinion as I don't want to spend a lot of bucks on just replacing parts as these relays are somewhat pricey.
Thanks. in advance, for your help.
Answer:
Either of these could cause your issue.
I suggest you take it to a local independent MB shop for correct diagnosis.
There are several other possible causes.
Possible local MB shops
http://www.mercedesshop.com/shopforum/forumdisplay.php?f=14
Related Articles
whunter
Expertise
Mercedes Benz diesel 1960 - 1985. Rolls-Royce or Bentley 1959 - 1978. Jaguar 1960 - 1989. MG 1959 - 1985. British 1923 - 1969. Micro and mini cars, an area of interest and study, I will try to answer questions on these. Domestic car/light truck 1903 - 1975
Experience
30 years Automotive Field Experience.
ASE Double Master Mechanic.
Organizations
ACTIVE MEMBERSHIPS:
Cadillac-LaSalle Club http://www.cadillaclasalleclub.org/
Rolls-Royce Owners Club http://www.rroc.org/
Lake Michigan Region
Motor Region http://www.rroc-mr.org/index.htm
Ohio Region
Modern Car Society http://www.rroc.org/members/regions/mcs/
Silver Cloud Society http://www.cloudsociety.org/
Rolls-Royce Foundation http://www.rollsroycefoundation.com/
Rolls-Royce Owners' Club of Australia http://www.rroc.org.au/cgi-bin/newforum/discus.pl
Mercedes-Benz Club of America http://mbca.cartama.net
International Stars Section http://www.internationalstars.org/
mercedesshop.com Diesel Discussion http://www.mercedesshop.com/shopforum/
JAGUAR CLUBS OF NORTH AMERICA http://jcna.com/forums/index.php
Jag-lovers - Jaguar Enthusiasts http://www.jag-lovers.org/
BMW CCA http://bmwcca.org
Motor City Chapter BMW CCA http://www.mpowerclub.com/cca/index.pl?cat_id=6
http://www.bmw-forums.com/forum/index.php?
Publications
Rolls-Royce and Bentley, Modern Lady.
Education/Credentials
ASE CERTIFIED: Master Auto Technician.
Brakes, Engine Repair, Auto: Engine Performance, Auto: Suspension and Steering,
Heating & Air Conditioning, Auto: Electrical/Electronics systems, Manual Drive Train and Axles
Automatic Trans/Transaxle
ASE CERTIFIED: Master Med/Hvy Truck Technician.
Brakes, Diesel Engines, Gasoline Engines, Electrical systems, Suspension & Steering, Drive
ASE CERTIFIED: Alt. Fuels: Light Vehicle Compressed Natural Gas
ASE CERTIFIED: Body: Mechanical & Electrical components
GM, Steering service class.
GM, Vibration correction training class.
ISO 9000 Training.
Blueprint Reading and Engineering Drawing Interpretation:
Study of Steam Power, Certificate of Achievement:
DALE CARNEGIE TRAINING COURSE:
Refrigeration applied electricity and heating Certification:
Refrigerant Transition and Recovery, residential and commercial service.
Refrigerant Transition and Recovery, (IMACA).
BASIC Skills:
Welding: ARC/Mig/tig and gas. Blue print reading/layout, steel erection and rigging, wiring AC/DC, hydraulics, pneumatics, some lathe, mill, fabrication and instrumentation experience.
©2012 About.com, a part of The New York Times Company. All rights reserved.