Quote:
Originally Posted by theflystyle
Attached is the only circuit diagram I found with the resistor and fuel control module included. What really bothers me is that the resistance measured on the fuel resistor (R34 in the diagram) reads a resistance of 1.2 ohm (.2 is my multimeter’s probe resistance). Yet when I unplug it, the car starts. When its plugged in it does not.
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Great, exactly what I needed.
When the ignition is turned on the fuel pump is supplied with a positive supply via the fuel pump relay and fuses SB4 and No. 16 but overall switching of the pump relay and therefore the pump, depends on the ECU completing the negative ground circuit via d23.
The pump receives its negative supply via two alternatives, i.e. the resistor R34 or the fuel pump modulator switching transistors which are controlled via the ECU.
The resistor will provide a reduced voltage and therefore limited pump speed in the event of the pump modulator or its control failing. The resistor will also prevent full zero voltage in respect of pulse width modulation speed control of the pump.
Under normal circumstances pump speed and therefore pressure, will be controlled via the modulator and ultimately by the ECU by means of pulse width modulation.
The pump will run at a reduced speed with the pump modulator disconnected.
I presume that you are reading the value of the resistor with it unplugged. It would appear certain that the resistance value is too low but I do not have the specified figure. This would result in the resistor circuit overriding control via the modulator as would a short circuit to ground within the resistor housing.
Can you locate the correct specified value of the resistor?