Mechanics

FUEL INJECTOR RELAYS

1988 Alfa Romeo Spider

Engine Performance problem
1988 Alfa Romeo Spider 4 cyl Two Wheel Drive Manual 85000 miles

THE FUEL INJECTORS DO NOT ALLOW FUEL INTO THE ENGINE. I CAN SPRAY ETHER AND GET THE ENGINE RIGHT OFF. NEW FUEL PUMPS, NEW LINES, CLEAN FUEL TANK. OTHER TECH.'S SUGGEST EITHER OF THE 2 ON BOARD COMPUTERS OR A BOSCH RELAY IS FAILING. ALL THERE PARTS ARE MOUNTED INSIDE THE CAR BEHIND THE SEATS. THE RELAY SEEMS TO HAVE A BURN SMELL, WITH COVER REMOVED I SEE NOT BURNS OR CRACKS VISIBLE TO ME. I CANNOT LOCATE ANYONE YET TO TEST THE TWO COMPUTERS, BUT I THINK I SHOULD LOCATE AND REPLACE THE RELAY FIRST. BY THE WAY I CANNOT LOCATE A SOURCE FOR THE RELAY YET.
PLEASE MAKE ANY SUGGESTIONS YOU CAN.
THANKS
BILL EVANS
P.S.
I WOULD LOVE TO GET THE CAR RUNNING SO I CAN BE BACK IN AN OLD SPORTS CAR THAT IS A LOT OF FUN TO DRIVE.
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Bill Evans
September 9, 2009.



http://www.2carpros.com/how_to/how_do_i_check_a_relay.htm
Go here and test the relays before replacing them.
Also I show three spyders, which model is yours?
This covers all three...ELECTRIC FUEL PUMP(S) Fuel under pressure from electric fuel pump flows through a fuel damper, fuel filter, injector fuel rail and fuel pressure regulator. Fuel pump(s) may be located on frame rail, in fuel tank or both. Electrical power for fuel pump operation during cranking mode is provided from starter relay via the fuel pump relay (if equipped) and ECU. FUEL PRESSURE REGULATOR The pressure regulator is a sealed unit which is divided by a diaphragm into 2 chambers (fuel and spring chambers). The fuel chamber receives fuel through the inlet side from the injector fuel rail. The spring chamber is connected to intake manifold vacuum. At idle, intake manifold vacuum is high. The diaphragm is pulled down by intake manifold vacuum. Any excessive fuel is returned to the fuel tank. As the throttle is depressed, intake manifold vacuum decreases. The regulator spring overcomes manifold vacuum increasing fuel pressure. FUEL INJECTORS A fuel rail links the fuel pressure regulator with the fuel injectors. Each cylinder is provided with a solenoid-operated injector which sprays fuel toward the back of each intake valve. ELECTRONIC CONTROL UNIT (ECU) All components of the control system are electrically connected to the ECU. The ECU is a pre- programmed computer which receives and interprets data from various sensors to calculate the amount of fuel required by the engine to maintain efficiency with minimum exhaust emissions. The oxygen sensor informs the ECU of oxygen content of exhaust gases and the ECU constantly adjusts the air/fuel ratio by controlling the injector "on" time. An automatic function of the ECU is to provide fuel enrichment whenever engine is cranked, regardless of engine temperature. This is activated by a direct electrical connection from the starter circuit to the ECU (most models). The ECU is a sealed unit, and no service is required.

Merlin2021
Sep 10, 2009.


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