help! my 88 260e runs for 4sec then dies
After that
http://www.autohausaz.com/search/pro...ition%20Sensor
if bad,not good,easy diy.

where are you located?If you are not a diy type of owner before you throw a bunch of parts at it,it might be a good idea to have someone with a tester check the sensor values.
This is a safety circuit designed to prevent fuel from being pumped into an engine that is not running...i.e. broken fuel line
TT on a M103-12V is surprisingly fast, even at 7psi boost

Below is a wiring diagram with the tach/speed signal highlighted.
More then likely the problem is the fuel pump relay if you have the speed signal.
If you don't have the speed signal it could be as basic as the crank sensor or a problem with your KE control.
Start with the basics as it's the least expensive path
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Bypass the feed from the relay to the fuel pump with a jumper so you have voltage direct to the pump.
In essence taking this function of the relay out of the circuit.
Monitor the speed signal to see if it maintains beyond a few seconds.
If it does then you proved this input valid.
Possibility then that it is a defective fuel pump relay which is dropping out in spite of the available speed signal.
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If you are able to read the speed signal at the relay while the engine continues to run, then replace the relay as it probably is dropping out when it should be holding.
If you don't read the speed signal, then check the crank sensor where the signal originates.



