Hello, I have a 1987 Volvo 740 that isn't getting power to the injectors. I have replaced the following parts: wiring harness, fuel pump relay, noise suppression relay, ignition amplifier, and ecu. All help is very much appreciated and thank you for your time.

 

So, you get fuel? What happens if you squirt some starting fluid into the intake?
This car has a Hall sensor at the distributor, was that part of the wiring harness you replaced?

 

yes I just replaced the whole fuel system and I made sure it’s getting at least 38psi and no I have not heard of that component does it control fuel injection timing? For example when it shoots fuel into the combustion chamber? And yes it will start on starting fluid it’s just not getting fuel into the combustion chambers

 

The Hall sensor controls exactly that, makes sure it's OK and the coaxial cable that leads to it.

 

How would I go about checking the Hall Sensor? Is there some kind of measurement I can do with an ohm meter?

 

The tachometer needle jumps slightly as you crank engine over if the Hall sensor is working, but the needle lays dead if the sensor is not working.

Full Hall Sensor Test: Undo the distributor connector. When the ignition is ON the Voltage between positive terminal (red lead -Nr. 3) and ground should be approx. 11V. Voltage between (blue lead - Nr.2; middle one) and ground should be 5V although if you put it on a scope you would see the sharp rise and fall from 12v to ground as the distributor rotates. Pulse frequency varies as rpm is increased. . Resistance between (black lead - Nr. 1) and ground should be close to zero Ohms. Undo connector from the control unit (above the brake pedal) and remove the sealing washers (plastic inserts on the side of the connector). Replace connector without cover or sealing washers.

- Disconnect the/red and blue leads from ignition coil. - Measure voltage between terminal 24 at rear of control unit connector (blue lead) and ground. NOTE: Connector must be attached to control unit. Switch on ignition. Turn crankshaft by hand. Voltage should indicate OVER 1.8V each time a vane passes Hall generator. Instrument should read approx."0" (0 - 0.7V) each time an opening passes Hall generator. The correct voltage is less than 0.7V or more than 1.8V.

 

Awesome, thank you so much for the help and I’ll let you know if that’s my problem. Have a great day!

 

The hall sensor isn't the problem, do you have any other suggestions?