Help - stalling 420SEL

1979-1991 280SE, 300SE, 300SEL, 380SE, 380SEL, 380SEC, 420SE, 420SEL, 420SEC, 500SE, 500SEL, 500SEC, 560SEL, 560SEC

Help - stalling 420SEL

Postby Beamer » Fri 11 Aug, 2017 9:08 pm

After more than 2 years of completely trouble free driving, my 420SEL has decided to develop its first issue - while 600kms from home and with 1,500+ kms to be done over the next week.

The car has started to stall with no warning. There is no spluttering - it just dies immediately (feeling more electrical than fuel related). It has only happened so far when the car is warm. On several warm starts today, it would take 4 or 5 tries to start the car - it will start, but die immediately. It has also stalled half a dozen times while driving - a few times while coming to a stop at an intersection, and also a few times at 110kmh on the open road (in which case it catches again straight away and continues on its after a bit of a hiccough).

Not being at home, nor near a good service/parts centre for a few days, my options are a bit limited.

I have done a bit of googling - am I right to suspect the fuel pump relay? I could probably get one sent to my hotel and exchange it in the next few days, but I'm reluctant to spend the money on a new relay if there is nothing wrong with it. Are there other possible suspects such that this might just be a waste of money?

(The OVP relay is only 18 months old so that shouldn't be the problem.)

Thanks in advance for any help.


Sent from my iPad using Tapatalk
Chris
___________________________
Today: 1988 W126 420SEL
Yesterday: 1976 C107 450SLC
User avatar
Beamer
S Class
 
Posts: 90
Joined: Fri 14 Dec, 2012 2:59 pm
Location: Adelaide

Re: Help - stalling 420SEL

Postby MercMad West Australian » Sat 12 Aug, 2017 12:39 am

sounds exactly like a failing fuel pump relay.

could also be a failing crank position sensor too which are notorious for mis-behaving once hot, or any number of ignition related problems. But keep it simple and check the basics first, better to get it checked out than attempt a shotgun approach. Theres always old school merc specialists around.


The engine will run in failsafe old school K-jet mode when the OVP fails / engine KE-jet ecu fails or not even present. In many cases on o2 sensor cars it will actually pull harder too, so it's not going to be that.
1990 300E-24
User avatar
MercMad West Australian
Zeppelin
 
Posts: 428
Joined: Sun 08 Dec, 2013 2:23 pm
Location: Perth

Re: Help - stalling 420SEL

Postby Beamer » Sat 12 Aug, 2017 8:18 pm

Thanks MercMad. The car has been fine today (but covered many fewer kms), so we will press on (another 600kms to do tomorrow) until I can find someone to take a look at it.

Does anyone have any suggestions for a Merc specialist in the Lakes Entrance area?
Chris
___________________________
Today: 1988 W126 420SEL
Yesterday: 1976 C107 450SLC
User avatar
Beamer
S Class
 
Posts: 90
Joined: Fri 14 Dec, 2012 2:59 pm
Location: Adelaide


Return to W126

Who is online

Users browsing this forum: No registered users and 3 guests