[W126 Coupe] 1985 500 SEC dies in traffic

[Josh Allen]

On 8/23/2010 7:39 AM, AZTECPILOT at aol.com wrote:

> Check your fuel control relay. My 560 SEC did the same thing, getting 

> progressively worse over a ninety day period. It would stall, then 

> restart in a few minutes and run ok for a few days. It turned out to 

> be the fuel control relay. The relay was replaced and have had no 

> trouble for the past four years. About $100 bucks in an independent 

> garage.

> Tom Seitz


If you troubleshoot to an intermittent fuel relay, and are at all 
capable with a soldering iron, take a shot at repairing the one you have 
before coughing up for a new one.

In the case of my car, I found that the solder joints to a few of the 
high current connections had failed, visibly showing as a black ring 
around the post of one of the connections at the edge of the circuit 
board, and around one or two of the relay connections to the board.

To test if that was actually the cause, I used a piece of spring steel 
(a handy screw driver would work...) to push the existing solder around 
the failed connections into contact with the post, and found that the 
fuel pump was working again.
I then resoldered the connections, and a few others while I was there, 
and have had no issues with it since.


Just my $.02 or maybe $.03, but I figure it's worth a try.

-Josh
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